Associations
(
英語
)
由BioImages, the virtual fieldguide, UK提供
Foodplant / pathogen
Armillaria mellea s.l. infects and damages Tsuga heterophylla
Foodplant / saprobe
fruitbody of Mycena capillaripes is saprobic on dead, decayed needle of litter of Tsuga heterophylla
Comments
(
英語
)
由eFloras提供
Tsuga heterophylla is a dominant species over much of its broad distributional range. It has become the most important timber hemlock in North America. The wood is superior to that of other hemlocks for building purposes and it makes excellent pulp for paper production.
Tsuga × jeffreyi (Henry) Henry was described from southwestern British Columbia and western Washington as a hybrid between T . heterophylla and T . mertensiana . Hybridization is rare, if it occurs at all, and it is therefore of little consequence (R.J. Taylor 1972). At the upper elevational limits of its distribution and under stressful conditions, T . heterophylla tends to resemble T . mertensiana , e.g., leaves are less strictly 2-ranked and stomatal bands on the abaxial leaf surfaces are less conspicuous than at lower elevations.
Western hemlock ( Tsuga heterophylla ) is the state tree of Washington.
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- cc-by-nc-sa-3.0
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- Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
Description
(
英語
)
由eFloras提供
Trees to 50m; trunk to 2m diam.; crown narrowly conic. Bark gray-brown, scaly and moderately fissured. Twigs yellow-brown, finely pubescent. Buds ovoid, gray-brown, 2.5--3.5mm. Leaves (5--)10--20(--30)mm, mostly appearing 2-ranked, flattened; abaxial surface glaucous with 2 broad, conspicuous stomatal bands, adaxial surface shiny green (yellow-green); margins minutely dentate. Seed cones ovoid, (1--)1.5--2.5(--3) ´ 1--2.5cm; scales ovate, 8--15 ´ 6--10mm, apex round to pointed. 2 n =24.
- 許可
- cc-by-nc-sa-3.0
- 版權
- Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
Habitat & Distribution
(
英語
)
由eFloras提供
Coastal to midmontane forests; 0--1500m; Alta., B.C.; Alaska, Calif., Idaho, Mont., Oreg., Wash.
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- cc-by-nc-sa-3.0
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- Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
Synonym
(
英語
)
由eFloras提供
Abies heterophylla Rafinesque, Atlantic J. 1: 119. 1832
- 許可
- cc-by-nc-sa-3.0
- 版權
- Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
Common Names
(
英語
)
由Fire Effects Information System Plants提供
western hemlock
Pacific hemlock
west coast hemlock
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Description
(
英語
)
由Fire Effects Information System Plants提供
More info for the term:
treeWestern hemlock is a large, native, evergreen tree. At maturity it is
generally 100 to 150 feet (30-46 m) tall and 2 to 4 feet (0.6-1.2 m) in
trunk diameter [
72]. On best sites, old-growth trees reach diameters
greater than 3.3 feet (1 m); maximum diameter is about 9 feet (3 m).
Heights of 160 to 200 feet (49-61 m) are not uncommon; maximum
height has been reported as 259 feet (79 m) [
57].
Western hemlock has a long slender trunk often becoming fluted when
large and has a short, narrow crown of horizontal or slightly drooping
branches. The needles are short-stalked and 0.25 to 0.87 inch (6-22 mm)
long, flat and rounded at the tip. The twigs are slender [
72]. The
bark is thin (1 to 1.5 inches [0.39-0.59 cm]) even on large trees; young
bark is scaly and on old trunks it is hard with furrows separating wide
flat ridges [
60]. Western hemlock is shallow rooted and does not
develop a taproot. The roots, especially the fine roots, are commonly
most abundant near the surface and are easily damaged by harvesting
equipment and fire. Maximum ages are typically over 400 years but less
than 500 years. The maximum age recorded is in excess of 700 years
[
57].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Distribution
(
英語
)
由Fire Effects Information System Plants提供
Western hemlock occurs in the Coast Ranges from Sonoma County California
to the Kenai Peninsula in Alaska. Inland it occurs along the western
and upper eastern slopes of the Cascade Range in Oregon and Washington
and west of the Continental Divide in the northern Rocky Mountains of
Montana and Idaho, north to Prince George, British Columbia
[
10,
56,
57,
78].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Fire Ecology
(
英語
)
由Fire Effects Information System Plants提供
More info for the terms:
fire intensity,
fire interval,
fire regime,
forest,
frequency,
habitat type,
lichen,
mean fire interval,
mesic,
wildfireWestern hemlock has a low degree of fire resistance [
20,
58]. It has
thin bark, shallow roots, highly flammable foliage, and a low-branching
habit which make it very susceptible to fire. Western hemlock tends to
form dense stands and its branches are often lichen covered, which
further increases its susceptibility to fire damage [
15,
29,
57].
The frequency of fire in western hemlock stands tends to be low because
it commonly occupies cool mesic habitats which offer protection from all
but the most severe wildfire [
22,
64]. In western hemlock forests of the
Pacific Northwest, the fire regime is generally from 150 to 400 or more
years [
58]. At Desolation Peak, Washington, western hemlock forest
types had a mean fire interval of 108 to 137 years [
3]. In the western
hemlock/Pachistima habitat type described by Daubenmire and Daubenmire
[
21], the mean fire interval is 50 to 150 years, and fire intensity in
these stands is quite variable [
9]. In the Bitterroot Mountains,
western hemlock stands are more likely to be destroyed by
stand-replacing fires because they often occupy steep montane slopes
which favor more intense burning [
8].
FIRE REGIMES : Find fire regime information for the plant communities in which this
species may occur by entering the species name in the
FEIS home page under
"Find FIRE REGIMES".
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Fire Management Considerations
(
英語
)
由Fire Effects Information System Plants提供
Fire danger increases with the increasing volume of logging residue.
Logging old-growth stands or western hemlock can leave huge volumes of
residue compared with logging young stands, which leave little residue.
Burning cleans up the area and facilitates planting. Therefore burning
is often favored by land managers who intend to plant Douglas-fir to
obtain a mixture of Douglas-fir and western hemlock. The general trend
in western hemlock management, however, is away from broadcast burning
except where a huge accumulation of residues constitutes a fire hazard
[
64].
Burning in western hemlock stands is a valuable treatment when seedlings
and saplings are infected with dwarf mistletoe and need to be destroyed.
Fire is helpful in rehabilitation of brushy areas; burning brush to
ground level facilitates planting and favors planted seedlings in
keeping ahead of the brush sprouts [
64].
Fire spreads more slowly in western hemlock slash than in western
redcedar slash. Western hemlock slash drops its foliage. The slash of
western hemlock is less flammable when chipped [
52]. Slash from western
hemlock/western redcedar/Alaska-cedar forests produce greater nutrient
losses to the atmosphere when the slash composition has a greater
proportion of Alaska-cedar and western redcedar. One can expect smaller
nutrient losses when western hemlock makes up the majority of the slash
[
28]. For further details on burning of western hemlock slash, refer to
the
Fire Case Study in the Alaska-cedar Fire Effects Information System
Species Review.
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Growth Form (according to Raunkiær Life-form classification)
(
英語
)
由Fire Effects Information System Plants提供
More info on this topic. More info for the term:
phanerophytePhanerophyte
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Habitat characteristics
(
英語
)
由Fire Effects Information System Plants提供
More info for the terms:
density,
fern,
herb,
shrub,
vineWestern hemlock thrives in humid areas of the Pacific Coast and northern
Rocky Mountains. Growth is best in mild, humid climates where frequent
fog and precipitation occur during the growing season. The best stands
occur in the humid coastal regions. In subhumid regions with relatively
dry growing seasons, western hemlock is confined primarily to northerly
aspects, moist stream bottoms, or seepage sites [
10,
57,
59]. In Alaska,
western hemlock attains its largest size on moist flats and low slopes
[
72].
Precipitation and temperature: In the coastal range, western hemlock
occurs on sites with a mean annual precipitation of less than 15 inches
(380 mm) in Alaska to at least 262 inches (6,650 mm) in British
Columbia. In the Rocky Mountains it occurs on sites with mean annual
precipitation ranging from 22 inches (560 mm) to at least 68 inches
(1,730 mm). Mean annual temperatures where western hemlock commonly
occurs range from 32.5 to 52.3 degrees Fahrenheit (0.3-11.3 deg C) on
the coast and 36 to 46.8 degrees Fahrenheit (2.2-8.2 deg C) in the Rocky
Mountains. The frost-free period within the coastal range of western
hemlock averages less than 100 to more than 280 days. In the Rocky
Mountains the frost-free period is 100 to 150 days [
57].
Elevation: The elevational range of western hemlock is from sea level
to 7,000 feet (2,130 m). On the coast, western hemlock develops best
between sea level and 2,000 feet (610 m); in the Rocky Mountains, it
develops best between 1,600 and 4,200 feet (490-1,280 m) [
57].
Soils: Western hemlock grows on soils derived from all bedrock types
(except serpentines) within its range [
57]. It grows well on
sedimentary, metamorphic, and igneous materials. Western hemlock is
found on most soil textures. Height growth, however, decreases with an
increase in clay content or soil bulk density. This is attributed to
inadequate soil aeration or the inability of roots to penetrate compact
soils. Western hemlock does not do well on sites where the water table
is less than 6 inches (15 cm) below the soil surface. The pH under
stands containing western hemlock ranges from less than 3.0 to nearly
6.0 in the organic horizons. The pH in the surface mineral horizons
ranges from 4.0 to 6.3 and that of the C horizons from 4.8 to 6.2. The
optimum range of pH for seedlings is 4.5 to 5.0. Western hemlock is
highly productive on soils with a high range of available nutrients.
The productivity of western hemlock increases as soil nitrogen increases
[
57].
In the Coast Range, western hemlock is commonly associated with the
following shrub species: vine maple (Acer circinatum), dwarf
Oregongrape (Mahonia nervosa), Pacific rhododendron (Rhododendron
macrophyllum), stink currant (Ribes bracteosum), salmonberry, trailing
blackberry (R. ursinus), Pacific red elder (Sambucus callicarpa),
Alaska blueberry (Vaccinium alaskaense), big huckleberry (V.
membranaceum), oval-leaf huckleberry (V. ovalifolium), evergreen
huckleberry (V. ovatum), and red huckleberry (V. parvifolium)
[
12,
31,
32,
57].
In the Rocky Mountains, western hemlock is commonly associated with the
following shrub species: Oregon grape (Mahonia repens), russet
buffaloberry (Shepherdia canadensis), birchleaf spirea (Spiraea
betulifolia), dwarf blueberry (Vaccinium caespitosum), globe huckleberry
(V. globulare), and grouse whortleberry (V. scoparium) [
55,
57,
59,
69,
73].
Common shrub associates of both coastal and Rocky Mountain regions are
as follows: Sitka alder (Alnus sinuata), snowbush ceanothus (Ceonothus
velutinus), oceanspray (Holodiscus discolor), rustyleaf mensziesia
(Menziesia ferruginea), devilsclub, Pacific ninebark (Physocarpus
capitatus), prickly currant (Ribes lacustre), thimbleberry, and common
snowberry (Symphoricarpos albus) [
57].
Common herb associates with western hemlock include maidenhair fern
(Adiantum pedatum), ladyfern (Athyrium filix-femina), deerfern (Blechnum
spicant), mountain woodfern (Dryopteris austriaca), oakfern
(Gymnocarpium dryopteris), swordfern (Polystichum munitum), bracken fern
(Pteridium aquilinum), vanillaleaf (Achlys triphylla), wild ginger
(Asarum caudatum), princes-pine (Chimaphila umbellata), queenscup
beadlily (Clintonia unifora), cleavers bedstraw (Galium aparine),
sweetscented bedstraw (G. triflorum), twinflower (Linnaea borealis),
one-sided pyrola (Pyrola secunda), feather solomonplume (Smilacina
racemosa), white trillium (Trillium ovatum), roundleaf violet (Viola
orbiculata), and beargrass (Xerophyllum tenax) [
55,
57,
59,
69,
73].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Habitat: Cover Types
(
英語
)
由Fire Effects Information System Plants提供
More info on this topic. This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
202 White spruce - paper birch
205 Mountain hemlock
206 Engelmann spruce - subalpine fir
210 Interior Douglas-fir
212 Western larch
213 Grand fir
215 Western white pine
218 Lodgepole pine
221 Red alder
222 Black cottonwood - willow
223 Sitka spruce
224 Western hemlock
225 Western hemlock - Sitka spruce
226 Coastal true fir - hemlock
227 Western redcedar - western hemlock
228 Western redcedar
229 Pacific Douglas-fir
230 Douglas-fir - western hemlock
231 Port-Orford-cedar
232 Redwood
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Habitat: Ecosystem
(
英語
)
由Fire Effects Information System Plants提供
More info on this topic. This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES22 Western white pine
FRES23 Fir - spruce
FRES24 Hemlock - Sitka spruce
FRES25 Larch
FRES26 Lodgepole pine
FRES27 Redwood
FRES28 Western hardwoods
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Habitat: Plant Associations
(
英語
)
由Fire Effects Information System Plants提供
More info on this topic. This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
More info for the term:
forestK001 Spruce - cedar - hemlock forest
K002 Cedar - hemlock - Douglas-fir forest
K003 Silver fir - Douglas-fir forest
K004 Fir - hemlock forest
K005 Mixed conifer forest
K006 Redwood forest
K008 Lodgepole pine - subalpine forest
K012 Douglas-fir forest
K013 Cedar - hemlock - pine forest
K014 Grand fir - Douglas-fir forest
K015 Western spruce - fir forest
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Immediate Effect of Fire
(
英語
)
由Fire Effects Information System Plants提供
More info for the term:
crown fireWestern hemlock is commonly killed by fire. High-severity fires often
destroy all western hemlock [
24]. After a severe crown fire at Olympic
Mountain, Washington, overstory western hemlock suffered 91 percent
mortality [
4]. Even light ground fires are damaging because the shallow
roots are scorched [
57]. Postfire mortality of western hemlock is
common due to fungal infection of fire wounds [
29]. Most western hemlock
seedlings are killed by broadcast burning [
27,
64].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Importance to Livestock and Wildlife
(
英語
)
由Fire Effects Information System Plants提供
More info for the terms:
climax,
cover,
forest,
seed,
treeRoosevelt elk and black-tailed deer browse western hemlock in coastal
Oregon, Washington, and British Columbia [
57]. In the Oregon Cascades
deer mice consumed about 22 percent of the western hemlock seed fall.
This consumption occurred just before or during the germination process
[
76]. Black bear girdle pole-size western hemlock and larger saplings
or damage the bark at the base of the trees. Snowshoe hare and rabbit
clip off the main stems of western hemlock seedlings. Mountain beaver
clip the stems and lateral branches of seedlings and girdle the base of
saplings [
57].
Old-growth western hemlock stands provide hiding and thermal cover for
many wildlife species. In the southern Selkirk Mountains of northern
Idaho, northeastern Washington, and adjacent British Columbia, grizzly
bear have been known to use heavily timbered western hemlock forests
[
48]. In the western Oregon Cascades, western hemlock provides habitat
for many species of small mammals, including the northern flying
squirrel and red tree vole [
7,
67]. In Washington and Oregon, the
northern spotted owl is often found in forests dominated by Douglas-fir
(Pseudotsuga menziesii) and western hemlock. The majority of barred
owls observed in British Columbia have occurred in the Columbia Forest
Biotic Area in which western hemlock and western redcedar are the major
climax species [
6]. Western hemlock is used for nest trees by cavity
nesting bird species such as the yellow-bellied sapsucker and northern
three-toed woodpecker [
51].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Key Plant Community Associations
(
英語
)
由Fire Effects Information System Plants提供
More info for the terms:
association,
climax,
codominant,
cover,
cover type,
forest,
naturalWestern hemlock commonly occurs as a dominant or codominant on low- to
mid-elevation moist sites. In northern Idaho, plant communities
dominated by western hemlock occupy the moist, moderate temperature
sites within the maritime-influenced climatic zone of the northern Rocky
Mountains. Here, western hemlock can be found as the climax dominant
from 2,500 to 5,500 feet (760-1,680 m) and can dominate sites of all
exposures and landforms except wet bottomlands where it is replaced or
codominant with western redcedar (Thuja plicata) [
19]. In the Gifford
Pinchot National Forest of Washington, the western-hemlock-dominated
zone includes the lower elevation moist forests of the western Cascades
[
68]. In Mount Rainier National Park, Washington, the western
hemlock/devil's club (Oplopanax horridus) community occupies wet
benches, terraces, and lower slopes at low elevations [
32]. The western
hemlock riparian dominance type in Montana described by Hansen and
others [
39] is an infrequent cover type restricted to northwestern
Montana on toe-slope seepages, moist benches, and wet bottoms adjacent
to streams. Published classifications identifying western hemlock as a
dominant or codominant are as follows:
Classification and management of riparian and wetland sites in northwest
Montana [
14].
Classification of montane forest community types in the Cedar River
drainage of western Washington, U.S.A. [
54].
The forest communities of Mount Rainier National Park [
32].
Forest habitat types of Montana [
59].
Forest habitat types of northern Idaho: A second approximation [
19].
Forest types of the North Cascades National Park Service complex [
5].
Forest vegetation of eastern Washington and northern Idaho [
21].
A guide to the interior cedar-hemlock zone, northwestern transitional
subzone (ICHg), in the Prince Rupert Forest Region, British
Columbia [
36].
Natural vegetation of Oregon and Washington [
31].
Plant association and management guide [
41].
Plant association and management guide for the western hemlock zone.
Gifford Pinchot National Forest [
68].
Plant association and management guide for the western hemlock zone: Mt.
Hood National Forest [
37].
Plant association and management guide. Willamette National Forest [
42].
A preliminary classification of forest communities in the central
portion of the western Cascades in Oregon [
25].
Preliminary forest plant association management guide. Ketchikan area,
Tongass National Forest [
23].
Preliminary forest plant associations of the Stikine area Tongass
National Forest [
70].
Preliminary plant associations of the Siskiyou Mountain province [
12].
Preliminary plant associations of the southern Oregon Cascade Mountain
Province [
11].
Reference material Daubenmire habitat types [
69].
Riparian dominance types of Montana [
39].
A study of the vegetation of southeastern Washington and adjacent Idaho
[
73].
Vegetation mapping and community description of a small western cascade
watershed [
40].
Vegetation of the Abbott Creek Research Natural Area, Oregon [
53].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Life Form
(
英語
)
由Fire Effects Information System Plants提供
More info for the term:
treeTree
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Management considerations
(
英語
)
由Fire Effects Information System Plants提供
More info for the terms:
competition,
forest,
natural,
seed,
seed tree,
selection,
treeInsects and disease: The major root and butt pathogens of western
hemolock are: Armillaria mellea, Heterobasidion annosum, Phaeolus
schweinitzii, Laetiporus sulphureus, Inenotus tomentosus, Poria
subacida, Phellinus weiri, and Indian paint fungus (Echinodontium
tinctorium) [
30,
57]. Western hemlock is severely damaged by Indian
paint fungus in the high Cascades; cull due to this rot may run as high
as 80 percent in old-growth stands [
30]. Dwarf mistletoe (Arceuthobium
campylopodum) is a common parasite on western hemlock which causes
wide-spread growth loss and mortality in old-growth stands [
62].
Important insects attacking western hemlock are a weevil (Steremnius
carinatus), western larch borer (Tetropium velutinum), western
blackheaded budworm (Acleris gloverana), western hemlock looper
(Lambdina fiscellaria lugubrosa), green striped forest looper
(Melanolophia imitata), saddleback looper (Ectropis crepuscularia), and
hemlock sawfly (Neodiprion tsugae). The western hemlock looper has
caused more mortality of western hemlock than any other insect pest.
Outbreaks can last 2 to 3 years on any one site. Although mortality is
greatest in old-growth western hemlock, vigorous 80- to 100-year-old
stands can also be severely damaged by this insect. The hemlock sawfly
is considered the second most destructive insect of western hemlock in
Alaska [
57].
Other damaging agents: Pole-sized and larger stands of western hemlock
are subject to severe windthrow. Uprooting is increased in areas where
a high water table or impenetrable layer in the soil causes trees to be
shallow rooted [
62]. Blowdown is a major problem in western hemlock
forests, and the need to leave windfirm borders is always present. If
only part of the stand will be removed, the leave trees need to be as
windfirm as possible [
64].
Western hemlock suffers frost damage in the Rocky Mountains, especially
along the eastern edge of its range [
57].
On droughty sites, top dieback is common; in exceptionally dry years,
entire stands of western hemlock saplings die [
57]. Western hemlock
seedlings and saplings are susceptible to sunscald following exposure of
young stems by thinning. Sunscald lesions often become infected with
decay organisms [
62].
Western hemlock is one of the conifers most sensitive to damage by
sulfur dioxide.
Spring applications of the iso-octyl esters of 2,4-D and 2,4,5-T in
diesel oil can kill up to 3 years of leader growth [
57].
Fertilization: The response of western hemlock to nitrogen fertilizer
is extremely variable. For overstocked stands, a combination of
precommercial thinning and fertilizer often gives the best response
[
57].
Silvicultural considerations: In terms of biomass production, western
hemlock forests are among the most productive forests in the world.
Natural stands of western hemlock along the Pacific Coast attain higher
yields than Douglas-fir stands having the same site index [
57,
64]. Pure
stands of western hemlock are so densely stocked that an acre of
100-year-old western hemlock forest can yield more timber (150,000 to
190,000 board feet on a good site) than a comparable stand of larger,
less dense Douglas-fir [
10,
64].
Western hemlock can be regenerated by most standard harvest methods. In
the past, clearcutting was the most common method used in western
hemlock stands [
64,
74]. As an aesthetically viable alternative to
clearcutting, shelterwood cutting has been proposed as a means of
controlling brush competition and favoring western hemlock seedlings
[
77]. The shelterwood method has been used successfully in even-aged
stands. Observations suggest that cutting of uneven-aged stands by the
individual tree selection method will be successful in obtaining western
hemlock regeneration [
38,
64]. In the grand fir (Abies
grandis)-cedar-hemlock ecosystem, Graham and Smith [
34] found that the
individual tree selection method of harvest promotes the regeneration
and growth of shade-tolerant species, such as western hemlock. The seed
tree method will work, but rarely is used in harvesting of western
hemlock stands because many seed trees blow down during wind storms
[
64].
A common problem in regeneration of western hemlock is overtopping by
competing vegetation such as alder, thimbleberry (Rubus parviflorus),
and salmonberry (Ribes spectabilis). When exposed to full sunlight
after clearcutting, these brush species tend to form dense thickets and
exclude hemlock regeneration. These species can be controlled with
herbicides [
64].
Western hemlock responds well to release after long periods of
suppression. Advance regeneration up to 4.5 feet (1.4 m) tall appears
to respond better to release than taller individuals. Poor response to
release has been noted for suppressed trees over 100 years old [
57].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Occurrence in North America
(
英語
)
由Fire Effects Information System Plants提供
AK CA ID MT OR WA AB BC
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Other uses and values
(
英語
)
由Fire Effects Information System Plants提供
Alaska Indians made coarse bread from the inner bark of western hemlock
[
72]. Young western hemlock saplings can be sheared to make excellent
hedges. In Britain western hemlock is often planted as an ornamental
[
46].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Phenology
(
英語
)
由Fire Effects Information System Plants提供
More info on this topic. More info for the terms:
cone,
phenology,
seed,
treeThe reproductive cycle of western hemlock occurs over 15 to 16 months
from the time of cone initiation in early summer, until seeds are shed
in the fall of the following year. Fertilization and seed development
occur in the second year. Phenology varies between coastal and interior
regions [
56,
57,
76]. Trees in the interior region or at higher
elevations begin development later in the spring and complete
development earlier in the fall than do trees growing in coastal and
low-elevation regions [
56].
At low-elevation coastal British Columbia locations, pollination
commonly occurs in early to mid-April, whereas in the interior of
British Columbia, it may occur from May until mid-June. Records from
western Washington and Oregon show that pollination may occur from
mid-April until late May [
56]. Fertilization occurs in coastal western
hemlock about mid-May. The time from pollination to seed release ranges
from 120 to 160 days in western hemlock. It can vary according to
weather and temperature during cone maturation. Dry, warm weather in
late summer may cause more rapid drying and earlier opening of cones
with consequently, earlier seed release. Wet, cool weather may delay
cone opening and seed release. Most seeds are shed in the fall when
cones first open [
50,
56,
76]. Cones may close in wet weather and reopen
more fully with subsequent dry weather. As a result, seeds may be shed
throughout the winter or even during the next spring. Mature cones
often persist on the tree throughout the second year but contain few
viable seeds [
56,
57].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Plant Response to Fire
(
英語
)
由Fire Effects Information System Plants提供
More info for the terms:
competition,
naturalBurning may or may not benefit natural regeneration of western hemlock.
The response of seedlings to burning varies according to aspect, slope,
latitude, climate, etc. After broadcast burning in coastal hemlock
zones, more seedlings were found in burned areas than in unburned areas
due to elimination of brush competition and reduction of dense patches
of slash [
76]. On Vancouver Island after the third growing season,
burned seedbeds had 58 percent more seedlings with better distribution
than unburned seedbeds [
57]. However, on a site near Vancouver, British
Columbia, due to sunscald, all new germinants on burned humus were dead
by mid-July [
76].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Post-fire Regeneration
(
英語
)
由Fire Effects Information System Plants提供
More info for the terms:
root crown,
secondary colonizerTree without adventitious-bud root crown
Secondary colonizer - off-site seed
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Regeneration Processes
(
英語
)
由Fire Effects Information System Plants提供
More info for the terms:
cone,
duff,
epigeal,
layering,
litter,
natural,
root collar,
seed,
stratification,
treeSeed production and dissemination: Western hemlock is generally a good
cone and seed producer. Cones may form on open-grown trees that are
less than 20 years old, but good cone crops usually do not occur until
trees are between 25 and 30 years old. Individuals usually produce some
cones every year and heavy cone crops every 3 or 4 years. Each cone
contains 30 to 40 seeds. The number of viable seeds ranges from fewer
than 10 to approximately 20 per cone [
18,
56]. Seeds are light and
small, ranging from 189,000 to 508,000 cleaned seeds per pound, with an
average of 260,000 seeds per pound (371,000-900,000/kg, average 530,000
seeds/kg) [
56,
63].
Western hemlock seeds have large wings enabling them to be distributed
over long distances. In open, moderately windy areas, most seeds fall
within 1,968 feet (600 m) of the parent tree. Some seeds can travel as
far as 3,772 feet (1,150 m) under these conditions. In dense stands,
most seeds fall much closer to the base of the tree [
56].
Germination: Germination is epigeal. Stratification for 3 to 4 weeks
at 33 to 39 degrees Fahrenheit (1-4 deg C) improves germination. The
optimum temperature for germination is 68 degrees Fahrenheit (20 deg C)
[
57,
63]. For each 9 degrees Fahrenheit (5 deg C) below the optimum, the
number of days required for germination is nearly doubled [
63]. Given
sufficient time (6-9 months) and an absence of pathogens, western hemlock
will germinate at temperatures just above freezing. Western hemlock
seeds remain viable only into the first growing season after seedfall
[
57]. Viability seems to vary between 36 and 55 percent with an average
of about 46 percent [
76].
Western hemlock seed appears to germinate well and seedlings grow well
on almost all natural seedbeds whether rotten wood, undisturbed bed duff
and litter, or bare mineral soil. The principal requirement for
adequate development on any seedbed appears to be adequate moisture.
For drier situations, mineral soils appear to be best for hemlock
seedlings [
76].
Seedling development: Most seedling mortality occurs in the first 2
years after germination [
76]. Seedlings are very shade tolerant but are
sensitive to heat, cold, drought and wind [
56]. In British Columbia,
the main cause of mortality appeared to be either drought or frost [
76].
Initial growth is slow; 2-year-old seedlings are commonly less than 8
inches (20 cm) tall. Once established, seedlings in full light may have
an average growth rate of 24 inches (60 cm) or more annually [
57]. In
inland regions, one study showed partial shade to be beneficial in
reducing mortality caused by high temperatures and drought. Once
seedlings are over 2 years old, survival appears to be very good [
76].
Vegetative reproduction: Western hemlock will reproduce vegetatively by
layering or cuttings. Seedlings that die back to the soil surface
commonly sprout from buds near the root collar. Sprouting does not
occur from the roots or the base of larger saplings. Western hemlock
grafts readily. Growth of grafted material is better than that of
rooted material [
57].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Regional Distribution in the Western United States
(
英語
)
由Fire Effects Information System Plants提供
More info on this topic. This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):
1 Northern Pacific Border
2 Cascade Mountains
4 Sierra Mountains
5 Columbia Plateau
8 Northern Rocky Mountains
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Successional Status
(
英語
)
由Fire Effects Information System Plants提供
More info on this topic. More info for the terms:
climax,
forest,
successionWestern hemlock is very shade tolerant. Only Pacific yew (Taxus
brevifolia) and Pacific silver fir are considered to have equal or
greater tolerance of shade than western hemlock. Western hemlock is
generally considered a climax species either alone or in combination
with its shade-tolerant associates, but it can be found in all stages of
succession [
57]. It is an aggressive pioneer because of its quick
growth in full overhead light and its ability to survive on a wide
variety of seedbed conditions [
29,
57]. It also invades seral stages of
forest succession after a forest canopy has formed [
35]. If several
centuries pass without a major disturbance, a climax of
self-perpetuating, essentially pure western hemlock can result [
10]. On
drier upland slopes in Glacier National Park, western hemlock often
achieves dominance over western redcedar. Western hemlock rarely
replaces western redcedar entirely [
35]. In Idaho, western white pine
(Pinus monticola) stands are slowly replaced by a western
hemlock-western redcedar climax [
52].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Taxonomy
(
英語
)
由Fire Effects Information System Plants提供
More info for the term:
naturalThe scientific name for western hemlock is Tsuga heterophylla (Raf.)
Sarg. [
57,
60]. There are no recognized subspecies, varieties, or forms.
A natural hybrid between western hemlock and mountain hemlock (Tsuga mertensiana),
Tsuga x jeffreyi (Henry) Henry, has been reported [
57].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Value for rehabilitation of disturbed sites
(
英語
)
由Fire Effects Information System Plants提供
More info for the term:
naturalWestern hemlock is suitable for planting on moist, nutrient very poor to
nutrient medium sites in pure or mixed species stands (mainly with
Pacific silver fir [Abies amabilis], Sitka spruce [Picea sitchensis],
alder [Alnus spp.], or western redcedar). Natural regeneration is
preferred over planted stock [
44]. Western hemlock is difficult to grow
in outdoor nurseries. Container-grown stock appears to result in higher
quality seedlings with less damage to roots and better survival than
bareroot stock [
57]. Methods for collecting, storing and planting
western hemlock seeds and seedlings have been detailed [
63].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Wood Products Value
(
英語
)
由Fire Effects Information System Plants提供
Western hemlock wood is recognized as an all-purpose raw material. It
is one of the best pulpwoods for paper and paper board products [
57,
72].
It is the principal source of alpha cellulose fiber used in the
manufacture of rayon, cellophane, and many plastics [
10]. Other uses
are lumber for general construction, railway ties, mine timbers, and
marine piling. The wood is suited also for interior finish, boxes and
crates, kitchen cabinets, flooring, and ceiling, gutter stock, and
veneer for plywood [
57,
72].
- 書目引用
- Tesky, Julie L. 1992. Tsuga heterophylla. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/
Distribution
(
西班牙、卡斯蒂利亞西班牙語
)
由IABIN提供
Chile Central
Associated Forest Cover
(
英語
)
由Silvics of North America提供
Western hemlock is either a major or a minor component in at least 20
forest cover types of the Society of American Foresters (6).
Pacific
Coast
Rocky Mountains
202 White Spruce-Paper Birch
x
205 Mountain Hemlock
x
x
206 Engelmann Spruce-Subalpine Fir
x
210 Interior Douglas-Fir
x
212 Western Larch
x
213 Grand Fir
x
215 Western White Pine
x
218 Lodgepole Pine
x
x
221 Red Alder
x
222 Black Cottonwood-Willow
x
223 Sitka Spruce
x
224 Western Hemlock
x
x
225 Western Hemlock-Sitka Spruce
x
226 Coastal True Fir-Hemlock
x
227 Western Redcedar-Western Hemlock
x
x
228 Western Redcedar
x
229 Pacific Douglas-Fir
x
230 Douglas-Fir-Western Hemlock
x
x
231 Port Orford-Cedar
x
232 Redwood
x
The forest cover types may be either seral or climax.
Tree associates specific to the coast include Pacific silver fir (Abies
amabilis), noble fir (A. procera), bigleaf maple (Acer
macrophyllum), red alder (Alnus rubra), giant chinkapin (Castanopsis
chrysophylla), Port-Orford-cedar (Chamaecyparis lawsoniana), Alaska-cedar
(C. nootkatensis), incense-cedar (Libocedrus decurrens), tanoak
(Lithocarpus densiflorus), Sitka spruce (Picea sitchensis),
sugar pine (Pinus lambertiana), redwood (Sequoia
sempervirens), and California laurel (Umbellularia californica).
Associates occurring in both the Pacific coast and Rocky Mountain
portions of its range include grand fir (Abies grandis), subalpine
fir (A. lasiocarpa), paper birch (Betula papyrifera), western
larch (Larix occidentalis), Engelmann spruce (Picea
engelmannii), white spruce (P. glauca), lodgepole pine (Pinus
contorta), western white. pine (P. monticola), ponderosa pine
(P. ponderosa), black cottonwood (Populus trichocarpa), Douglas-fir
(Pseudotsuga menziesii), Pacific yew (Taxus brevifolia), western
redcedar (Thuja plicata), and mountain hemlock (Tsuga
mertensiana).
Western hemlock is a component of the redwood forests on the coasts of
northern California and adjacent Oregon. In Oregon and western Washington,
it is a major constituent of the Picea sitchensis, Tsuga heterophylla,
and Abies amabilis Zones and is less important in the Tsuga
mertensiana and Mixed-Conifer Zones (7). In British Columbia, it is a
major element of the Tsuga heterophylla-Picea sitchensis, Tsuga
heterophylla-Abies amabilis, Tsuga heterophylla, Abies amabilis-Tsuga
heterophylla, and Abies amabilis-Tsuga mertensiana Vegetation
Zones; it is confined to a distinct understory portion or to moist sites
in the Pseudotsuga menziesii-Tsuga heterophylla and Pseudotsuga
menziesii Zones (25). In the Rocky Mountains, it is present in
the Thuja plicata and Tsuga heterophylla Vegetation Zones
and the lower portion of the Abies lasiocarpa Zone (26).
Various persons have described the plant associations and biogeocoenoses
in which western hemlock is found; more than 75 are listed for the west
coast and more than 30 for the Rocky Mountains (25). Little effort
has been made to correlate the communities with one another.
Because of its broad range, western hemlock has a substantial number of
understory associates. In its Pacific coast range, common shrub species
include the following (starred species are also common associates in the
Rocky Mountains): vine maple (Acer circinatum), Sitka alder* (Alnus
sinuata), Oregongrape (Berberis nervosa), snowbrush ceanothus*
(Ceanothus velutinus), salal (Gaultheria shallon), oceanspray*
(Holodiscus discolor), rustyleaf menziesia* (Menziesia
ferruginea), devilsclub* (Oplopanax horridus), Oregon boxwood*
(Pachistima myrsinites), Pacific ninebark* (Physocarpus
capitatus), Pacific rhododendron (Rhododendron macrophyllum), stink
currant (Ribes bracteosum), prickly currant* (R. lacustre),
thimbleberry* (Rubus parviflorus), salmonberry (R.
spectabilis), trailing blackberry (R. ursinus), Pacific red
elder (Sambucus callicarpa), common snowberry* (Symphoricarpos
albus), Alaska blueberry (Vaccinium alaskaense), big
huckleberry (V. membranaceum), ovalleaf huckleberry (V.
ovalifolium), evergreen huckleberry (V. ovatum), and red
huckleberry (V. parvifolium). The following are other common
associates in the Rocky Mountains: creeping western barberry (Berberis
repens), russet buffaloberry (Shepherdia canadensis), birchleaf
spirea (Spiraea betulifolia), dwarf blueberry (Vaccinium
caespitosum), globe huckleberry (V. globulare), and grouse
whortleberry (V. scoparium).
Common herbaceous species include the ferns: maidenhair fern (Adiantum
pedatum), ladyfern (Athyrium filix-femina), deerfern (Blechnum
spicant), mountain woodfern (Dryopteris austriaca), oakfern
(Gymnocarpium dryopteris), swordfern (Polystichum munitum),
and bracken (Pteridium aquilinum). Herb associates include
vanillaleaf (Achlys triphylla), wild ginger (Asarum caudatum),
princes-pine (Chimaphila umbellata), little princes-pine (C.
menziesii), queenscup (Clintonia uniflora), cleavers bedstraw
(Galium aparine), sweetscented bedstraw (G. triflorum), twinflower
(Linnaea borealis), Oregon oxalis (Oxalis oregana), one-sided
pyrola (Pyrola secunda), feather solomonplume (Smilacina
racemosa), starry solomonplume (S. stellata), trefoil
foamflower (Tiarella trifoliata), coolwort foamflower (T.
unifoliata), white trillium (Trillium ovatum), roundleaf
violet (Viola orbiculata), evergreen violet (V. sempervirens),
and common beargrass (Xerophyllum tenax).
Climate
(
英語
)
由Silvics of North America提供
Western hemlock thrives in a mild, humid climate where frequent fog and
precipitation occur during the growing season. Best stands are in the
humid and superhumid coastal regions. In subhumid regions with relatively
dry growing seasons, western hemlock is confined primarily to northerly
aspects, moist stream bottoms, or seepage sites.
Within the coastal range of western hemlock, mean annual total
precipitation ranges from less than 380 mm (15 in) in Alaska to at least
6650 mm (262 in) in British Columbia. The range in the Rocky Mountains is
560 mm (22 in) to at least 1730 mm (68 in) (25).
Mean annual temperatures range from 0.3° to 11.3° C (32.5°
to 52.3° F) on the coast and 2.2° to 8.2° C (36.0° to
46.8° F) in the Rocky Mountains. Observed mean July temperatures lie
between 11.3° and 19.7° C (52.3° and 67.5° F)
along the coast and 14.4° and 20.6° C (58.0° and 69.0°
F) in the interior. Mean January temperatures reported for the two areas
range from -10.9° to 8.5° C (12.4° to 47.3° F) and
-11.1° to -2.4° C (12.0° to 27.6° F), respectively.
Recorded absolute maximum temperature for the coast is 40.6° C (105.0°
F) and for the Rocky Mountains, 42.2° C (108.0° F). Absolute
minimum temperatures tolerated by western hemlock are -38.9° C (-38.0°
F) for the coast and -47.8° C (-54.0° F) for the interior.
The frost-free period within the coastal range of western hemlock
averages less than 100 to more than 280 days (25). In the Rocky Mountains,
the frost-free period is 100 to 150 days (20).
Damaging Agents
(
英語
)
由Silvics of North America提供
Many agents adversely affect the growth,
health, and quality of western hemlock trees and stands.
Because of its thin bark and shallow roots, western hemlock is highly
susceptible to fire. Even light ground fires are damaging. Prescribed
burning is an effective means of eliminating western hemlock advance
regeneration from a site.
Because of its shallow roots, pole-size and larger stands of western
hemlock are subject to severe windthrow. Thousands of hectares of young
stands dominated by coastal western hemlock have originated after such
blowdown.
Western hemlock suffers frost damage in the Rocky Mountains, especially
along the eastern edge of its range where frost-killed tops are reported
(20,26). Snowbreak occurs locally; it appears to be most common east of
the Cascade and Coast Mountains, and especially in the Rocky Mountains. On
droughty sites, top dieback is common; in some exceptionally dry years,
entire stands of hemlock saplings die. Suddenly exposed saplings may
suffer sunscald. Excessive amounts of soil moisture drastically reduce
growth.
Western hemlock is one of the species most sensitive to damage by sulfur
dioxide (16). Spring applications of the iso-octyl esters of 2,4-D and
2,4,5-T in diesel oil can kill leader growth of the last 3 years.
Severe fluting of western hemlock boles is common in southeast Alaska,
much less common on Vancouver Island, and relatively uncommon in
Washington and Oregon. There appears to be a clinal gradient from north to
south; the causal factor is not known.
No foliage diseases are known to cause serious problems for western
hemlock.
Dwarf mistletoe (Arceuthobium tsugense) is a serious parasite
along the Pacific coast from California nearly to Glacier Bay, AK; its
presence on western hemlock in the Rocky Mountain States is unconfirmed.
It increases mortality, reduces growth, lowers fiber quality, and provides
an entryway for decay fungi. Uninfected to lightly infected trees may have
a greater growth in volume (40 percent) and height (84 percent) than
severely infected trees; in mature stands, volume losses as high as 4.2 m³/ha
(60 ft³/acre) per year have been reported (29). Dwarf mistletoe in
western hemlock is easy to control; success is nearly 100 percent if
methods of sanitation are good.
Armillaria mellea, Heterobasidion annosum, Phaeolus schweinitzii,
Laetiporus sulphureus, Inonotus tomentosus, Poria subacida, and Phellinus
weiri are the major root and butt pathogens of western hemlock. Armillaria
mellea occurs widely, seldom kills trees directly, and is not a major
source of cull.
Heterobasidion annosum, the most serious root pathogen of
western hemlock, can limit the alternatives available for intensive
management (3). The incidence of infected trees in unthinned western
hemlock stands ranges from 0 to more than 50 percent. In some thinned
stands, every tree is infected. Heterobasidion annosum spores
colonize freshly cut stumps and wounds; the spreading mycelium infects
roots and spreads to adjacent trees through root grafts. Treating stumps
and wounds with chemicals can reduce the rate of infection.
Phellinus weiri is a common root pathogen where Douglas-fir is
or was a major component of the stand. In the Rocky Mountains, a similar
relationship may exist with western redcedar. Phellinus weiri rapidly
extends up into the bole of western hemlock. The first log is frequently
hollow; only the sapwood remains. The only practical controls for P.
weiri are pulling out the stumps and roots or growing resistant
species.
High risk bole pathogens include Echinodontium tinctorium,
Heterobasidion annosum, and Phellinus weiri. Echinodontium
tinctorium causes extensive decay in overmature stands in the Rocky
Mountains. It is less destructive in immature stands, although it is found
in trees 41 to 80 years old; 46 percent of the trees in this age group in
stands studied were infected. Echinodontium tinctorium is of
little consequence on the coast. Heterobasidion annosum spreads
from the roots into the bole of otherwise vigorous trees. On Vancouver
Island, an average of 24 percent (range 0.1 to 70 percent) of the volume
of the first 5-m (16-ft) log can be lost to H. annosum (24).
Rhizina undulata, a root rot, is a serious pathogen on both
natural and planted seedlings on sites that have been burned. It can kill
mature trees that are within 8 m (25 ft) of the perimeter of a slash burn
(3).
Sirococcus strobilinus, the sirococcus shoot blight, causes
dieback of the tip and lateral branches and kills some trees in Alaska;
the potential for damage is not known (27).
Of the important insects attacking western hemlock, only three do not
attack the foliage. A seed chalcid (Megastigmus tsugae) attacks
cones and seeds; the larva feeds inside the seed. This insect normally is
not plentiful and is of little consequence to seed production (14). A
weevil (Steremnius carinatus) causes severe damage in coastal
British Columbia by girdling seedlings at the ground line. In the Rocky
Mountains, the western larch borer (Tetropium velutinum) attacks
trees that are weakened by drought, defoliated by insects, or scorched by
fire; occasionally it kills trees (9).
Since 1917, there have been only 10 years in which an outbreak of the
western blackheaded budworm (Acleris gloverana) did not cause
visible defoliation somewhere in western hemlock forests (28). Extensive
outbreaks occur regularly in southeast Alaska, on the coast of British
Columbia, in Washington on the south coast of the Olympic Peninsula and in
the Cascade Range, and in the Rocky Mountains. In 1972, nearly 166 000 ha
(410,000 acres) were defoliated on Vancouver Island alone. Damage by the
larvae is usually limited to loss of foliage and related growth reduction
and top kill. Mortality is normally restricted to small stands with
extremely high populations of budworms.
The western hemlock looper (Lambdina fiscellaria lugubrosa) has
caused more mortality of western hemlock than have other insect pests.
Outbreaks last 2 to 3 years on any one site and are less frequent than
those of the budworm. The greatest number of outbreaks occurs on the south
coast of British Columbia; the western hemlock looper is less prevalent
farther north. Heavy attacks have been recorded for Washington and Oregon
since 1889. The insect is less destructive in the interior forests.
Although mortality is greatest in old growth, vigorous 80- to 100-year-old
stands are severely damaged.
Two other loopers, the greenstriped forest looper (Melanolophia
imitata) and the saddleback looper (Ectropis crepuscularia), cause
top kill and some mortality. The phantom hemlock looper (Nepytia
phantasmaria) in the coastal forest and the filament bearer (Nematocampa
filamentaria) play minor roles, usually in association with the
western hemlock looper (28).
The hemlock sawfly (Neodiprion tsugae) occurs over most of the
range of western hemlock. Its outbreaks often occur in conjunction with
outbreaks of the western blackheaded budworm. The larvae primarily feed on
old needles; hence, they tend to reduce growth rather than cause mortality
(9). The hemlock sawfly is considered the second most destructive insect
in Alaska (13).
Black bear girdle pole-size trees and larger saplings or damage the bark
at the base of the trees, especially on the Olympic Peninsula of
Washington. Roosevelt elk and black-tailed deer browse western hemlock in
coastal Oregon, Washington, and British Columbia. The snowshoe hare and
the brush rabbit damage hemlock seedlings, principally by clipping off the
main stem; clipping of laterals rarely affects survival of seedlings (5).
Mountain beaver clip the stems and lateral branches of seedlings and
girdle the base of saplings along the coast south of the Fraser River in
British Columbia to northern California. Four years after thinning,
evidence of girdling and removal of bark was present on 40 percent of the
trees (5). Mortality results from both kinds of damage.
Flowering and Fruiting
(
英語
)
由Silvics of North America提供
Western hemlock is monoecious; male and
female strobili develop from separate buds of the previous year. Female
strobili occupy terminal positions on lateral shoots, whereas the male
strobili cluster around the base of the needles (4). Flowering and
pollination begin from mid-April to late April in western Oregon and
continue into late May and June in coastal Alaska. The solitary, long (19
to 32 mm; 0.75 to 1.25 in), pendent cones mature 120 to 160 days after
pollination. Time of maturity of cones on the same branch is variable;
ripe cones change from green to golden brown. The cone-scale opening
mechanism does not appear to develop fully until late in the ripening
period. Seeds are usually fully ripe by mid-September to late September,
but cone scales do not open until late October. Empty cones often persist
on the tree for 2 or more years.
Although flowering may begin on 10-year-old trees, regular cone
production usually begins when trees reach 25 to 30 years of age. Mature
trees are prolific producers of cones. Some cones are produced every year,
and heavy crops occur at average intervals of 3 to 4 years; however, for a
given location, the period between good crops may vary from 2 to 8 years
or more. For example, in Alaska, good seed crops occur on an average of 5
to 8 years.
Genetics
(
英語
)
由Silvics of North America提供
A natural cross between western hemlock and mountain hemlock, Tsuga
x jeffreyi (Henry) Henry, has been reported from the Mount
Baker area in Washington. Analysis of polyphenolic pigment suggests that
chemical hybrids between western hemlock and mountain hemlock occur but
are rare. Intergeneric hybridization between western hemlock and spruce
has been discussed in the literature; although similarities exist between
the two genera, they do not suggest hybridization (31).
Albino individuals or those similarly deficient in chlorophyll have been
observed in the wild.
Growth and Yield
(
英語
)
由Silvics of North America提供
Western hemlock may form pure stands or be a
component of mixed stands. Young stands vary in stocking, but
understocking is infrequent. Natural 20-year-old stands can have 14,800 to
24,700 or more stems per hectare (6,000 to 10,000/acre). Stocking levels
of 1,480 to 1,790 stems per hectare (600 to 725/acre) at crown closure are
believed to provide the best yields if commercial thinnings are part of
the management regime (12). If thinnings are not planned, stocking levels
as low as 740 well-distributed trees per hectare (300/acre) can provide
maximum yields at rotation age (27).
The response of western hemlock to nitrogen fertilizer is extremely
variable. It appears to vary by geographic location and stocking level.
For overstocked stands, a combination of precommercial thinning and
fertilizer often gives the best response.
Comparative yield data from paired British plantations strongly suggest
that western hemlock commonly outproduces two of its most important
associates, Douglas-fir and Sitka spruce (1). Natural stands of western
hemlock along the Pacific coast attain appreciably higher yields than
Douglas-fir stands having the same site index (34); the weighted mean
annual increment of western hemlock for some common forest soils in
Washington is 33 to 101 percent more than the mean annual increment for
Douglas-fir (30). On the Olympic Peninsula, western hemlock out-produces
Douglas-fir by 25 to 40 percent. Similar relationships occur in south
coastal British Columbia (12). The higher mean annual increment of western
hemlock apparently is due to the ability of western hemlock stands to
support more trees per hectare; individual trees also have better form
than other species and hence better volume (at least 4 to 14 percent)
(34).
Mixed stands of western hemlock and Sitka spruce are especially
productive. In the Picea sitchensis Zone of Oregon and Washington,
the mean annual increment of such stands frequently exceeds 42 m³/ha
(600 ft³/acre). At higher elevations and farther north, mixed stands
of western hemlock and Pacific silver fir are also highly productive.
Yield data for natural stands are given in table 1. Volumes predicted
for normally stocked stands may actually underestimate potential yields by
20 to 50 percent. Data from British Columbia suggest greater yields can be
had if a high number of stems per hectare are maintained (12). Yields of
western hemlock on the best sites can exceed 1848 m³/ha (26,400 ft³/acre)
at 100 years of age.
Table 1- Characteristics of fully stocked, 100-year-old
western hemlock stands in Oregon (OR), Washington (WA), British Columbia
(BC), and Alaska (AK) (adapted from 2)
Average site index at
base age 100 years¹
Item
61 m or 200 ft
52 m or 170 ft
43 m or 140 ft
34 m or 110 ft
26 m or
85 ft
Avg. height, m
OR/WA
58.8
49.7
40.8
31.7
-
BC
-
50.0
40.8
31.7
22.3
AK
-
-
38.4
29.3
20.7
Avg. d.b.h., cm
OR/WA
58
54
49
42
-
BC/AK
-
44
40
31
22
Stocking², trees/ha
OR/WA
299
339
400
526
-
BC/AK
-
482
573
865
1,384
Basal area², m²/ha
OR/WA
83.3
81.7
79.0
75.3
-
BC/AK
-
75.5
73.0
67.5
59.9
Whole tree volume², ft³/acre
OR/WA
1771
1498
1218
938
-
BC
-
1449
1228
938
612
AK
-
-
1158
868
560
Avg. height, ft
OR/WA
192.0
163.1
133.9
104.0
-
BC
-
164.0
133.9
104.0
73.2
AK
-
-
126.0
96.1
67.9
Avg. d.b.h., in
OR/WA
23.0
21.4
19.2
16.5
-
BC/AK
-
17.5
15.6
12.4
8.8
Stocking², trees/acre
OR/WA
121
137
162
213
-
BC/AK
-
195
232
350
560
Basal area², ft²/acre
OR/WA
362.9
355.9
344.1
328.0
-
BC/AK
-
328.9
318.0
294.0
261.0
Whole tree volume², ft³/acre
OR/WA
25,295
21,394
17,406
13,405
-
BC
-
20,693
17,549
13,405
8,746
AK
-
-
16,549
12,405
8,003
¹Site indices
range within 4.6 m (15 ft) of the averages.
²Trees larger than 3.8 cm (1.5 in) in d.b.h.
Western hemlock forests are among the most productive forests in the
world. The biomass production of several western hemlock stands with a
site index (base 100 years) of 43 m (140 ft) was investigated at the
Cascade Head Experimental Forest near Lincoln City, OR. The biomass of
standing trees of a 26-year-old, nearly pure western hemlock stand was 229
331 kg/ha (204,614 lb/acre) and that of a 121-year-old stand with a spruce
component of 14 percent was 1 093 863 kg/ha (975,966 lb/acre). Net primary
productivity per year for these two stands was estimated to be 37 460 and
22 437 kg/ha (33,423 and 20,019 lb/acre). Net primary productivity appears
to peak at about 30 years, then declines rapidly for about 50 years.
Foliar biomass in the stands at Cascade Head averages 22 724 kg/ha (20,275
lb/acre) with a leaf area of 46.5 m²/m² (46.5 ft²/ft²)
(8, 10). By comparison, available data indicate much lower values for
highly productive Douglas-fir stands- 12 107 kg/ha and 21.4 m²/m²
(10,802 lb/acre and 21.4 ft²/ft² ), respectively.
On the best sites, old-growth trees commonly reach diameters greater
than 100 cm (39.6 in); maximum diameter is about 275 cm (108 in). Heights
of 50 to 61 m (165 to 200 ft) are not uncommon; maximum height is reported
as 79 m (259 ft). Trees over 300 years old virtually cease height growth
(27). Maximum ages are typically over 400 but less than 500 years. The
maximum age recorded, in excess of 700 years, is from the Queen Charlotte
Islands (16). Several major associates (Douglas-fir, western redcedar,
Alaska-cedar) typically reach much greater ages.
Reaction to Competition
(
英語
)
由Silvics of North America提供
Western hemlock is rated to be very
tolerant of shade. Only Pacific yew and Pacific silver fir are considered
to have equal or greater tolerance of shade than western hemlock.
Western hemlock responds well to release after a long period of
suppression. Advance regeneration 50 to 60 years old commonly develops
into a vigorous, physiologically young-growth stand after complete removal
of the overstory; however, poor response to release has been noted for
suppressed trees over 100 years old. Advance regeneration up to 1.4 m (4.5
ft) tall appears to respond better to release than taller individuals.
Because of its shade tolerance, it is an ideal species for management that
includes partial cutting; however, if it is present and the management
goal is for a less tolerant species, normal partial cutting practices are
not recommended.
Under conditions of dense, even-aged stocking, early natural pruning
occurs, tree crowns are usually narrow, and stem development is good.
Given unrestricted growing space, the quality of western hemlock logs is
reduced because of poorly formed stems and persistent branches. Trees that
develop in an understory vary greatly in form and quality.
The successional role of western hemlock is clear; it is a climax
species either alone or in combination with its shade-tolerant associates.
Climax or near-climax forest communities along the Pacific coast include
western hemlock, western hemlock-Pacific silver fir, western
hemlock-western redcedar, Pacific silver fir-western hemlock-Alaska-cedar,
and western hemlock-mountain hemlock. The longevity of some associates of
western hemlock makes it difficult to determine if some of these
near-climax communities will develop into pure western hemlock stands or
if western hemlock will ultimately be excluded.
Climax or near-climax communities in the Rocky Mountains include western
hemlock, western hemlock-western redcedar, and occasionally subalpine
fir-western hemlock. In the last community, western hemlock plays a
distinctly minor role (26).
Rooting Habit
(
英語
)
由Silvics of North America提供
Western hemlock is a shallow-rooted species; it
does not develop a taproot. The roots, especially the fine roots, are
commonly most abundant near the surface and are easily damaged by
harvesting equipment and fire.
Seed Production and Dissemination
(
英語
)
由Silvics of North America提供
There are 56,760 to 83,715
cones per hectoliter (20,000 to 29,500/bu). Each cone contains 30 to 40
small seeds. Extraction and cleaning yields an average of 0.79 kg of seed
per hectoliter (0.61 lb/bu) of cones. There are 417,000 to over 1,120,000
with an average 573,000 seeds per kilogram (189,000 to 508,000/lb; average
260,000). Slightly less than one-half of the seeds extracted from the
cones are viable.
In coastal Oregon, more than 19.8 million seeds per hectare (8
million/acre) were released during each of two good seed years from
100-year-old stands, or about 30.3 kg/ha (27 lb/acre). In 1951, a
hemlock-spruce stand in Alaska produced 96.4 kg/ha (86 lb/acre) of western
hemlock seed. In the Rocky Mountains, western hemlock consistently
produces more seed than its associates in the Tsuga heterophylla Zone.
Cone scales of western hemlock open and close in response to dry and wet
atmospheric conditions. Under wet conditions, seed may be retained in the
cones until spring. Western hemlock seed falls at a rate of 80 cm (31 in)
per second (27). Released in a strong wind, it can be blown more than 1.6
km (1 mi). In a wind of 20 km (12.5 mi) per hour, seed released at a
height of 61 m (200 ft) traveled up to 1160 m (3,800 ft); most fell within
610 m (2,000 ft) of the point of release (19). Seedfall under a dense
canopy is 10 to 15 times greater than that within 122 m (400 ft) of the
edge of timber in an adjacent clearcut.
Seedling Development
(
英語
)
由Silvics of North America提供
Western hemlock seeds are not deeply
dormant; stratification for 3 to 4 weeks at 1° to 4° C (33°
to 39° F) improves germination and germination rate. The germination
rate is sensitive to temperature; optimum temperature appears to be 20°
C (68° F). For each 5° C (9° F) drop below the optimum, the
number of days required for germination is nearly doubled. Given
sufficient time (6 to 9 months) and an absence of pathogens, western
hemlock will germinate at temperatures just above freezing (4).
Germination is epigeal. Western hemlock seeds remain viable only into the
first growing season after seedfall.
Provided adequate moisture is available, seed germination and germinant
survival are excellent on a wide range of materials. Seeds even germinate
within cones still attached to a tree. Western hemlock germinates on both
organic and mineral seedbeds; in Alaska, establishment and initial growth
are better on soils with a high amount of organic matter. Mineral soils
stripped of surface organic material commonly are poor seedbeds because
available nitrogen and mineral content is low.
In Oregon and Washington, exposed organic materials commonly dry out in
the sun, resulting in the death of the seedling before its radicle can
penetrate to mineral soil and available moisture. In addition, high
temperatures, which may exceed 66° C (150° F) at the surface of
exposed organic matter, are lethal. Under such moisture and temperature
conditions, organic seedbeds are less hospitable for establishment of
seedlings than mineral seedbeds (27). Burning appears to encourage natural
regeneration on Vancouver Island; after the third growing season, burned
seedbeds had 58 percent more seedlings with better distribution than
unburned seedbeds (17).
Decaying logs and rotten wood are often favorable seedbeds for western
hemlock. Decayed wood provides adequate nutrition for survival and growth
of seedlings (23). In brushy areas, seedlings commonly grow on rotten wood
where there is minimum competition for moisture and nutrients. Seedlings
established on such materials frequently survive in sufficient numbers to
form a fully stocked stand by sending roots into the soil around or
through a stump or log.
Because western hemlock can thrive and regenerate on a diversity of
seedbeds, natural regeneration can be obtained through various
reproduction methods, ranging from single-tree selection to clearcutting.
Through careful harvesting of old-growth stands, advance regeneration
often results in adequately stocked to overstocked stands.
Western hemlock is difficult to grow in outdoor nurseries.
Container-grown stock appears to result in higher quality seedlings, less
damage to roots, and better survival than does bare root stock.
Initial growth is slow; 2-year-old seedlings are commonly less than 20
cm (8 in) tall. Once established, seedlings in full light may have an
average growth rate of 60 cm (24 in) or more annually.
Soils and Topography
(
英語
)
由Silvics of North America提供
Western hemlock grows on soils derived from all bedrock types (except
possibly serpentines) within its range. It grows well on sedimentary
(argillites, shales, sandstones, limestones), metamorphic (gneisses,
marbles, quartzites, schists), and igneous (andesites, basalts, diorites,
gabbros, granites) materials. Under appropriate climatic conditions, it
thrives on all major landforms-colluvial, eolian, fluvial, lacustrine,
marine, morainal, residual, rock, and organic.
Western hemlock grows on a variety of soils and is a characteristic
species on soils of 6 of the 10 soil orders: Alfisols, Entisols,
Histosols, Inceptisols, Spodosols, and Ultisols; and on many great groups,
including: Fragiboralfs, Fragiudalfs, Hapludalfs; Fluvaquents,
Udifluvents, Quartzipsamments; Borofolists, Cryolfolists; Cryandepts,
Dystrandepts, Vitrandepts, Cryaquepts, Haplaquepts, Dystrochrepts,
Cryumbrepts, Haplumbrepts; Fragiaquods, Placohumods, Cryorthods,
Fragiorthods, Haplorthods; and Haplohumults. It is found on most soil
textural classes. Height growth, however, decreases with increasing clay
content or soil bulk density. This is attributed to inadequate soil
aeration (35) or the inability of roots to penetrate compact soils.
Western hemlock thrives on soils with perudic and udic soil moisture
regimes. If, however, internal soil drainage is restricted within 1 m (3.3
ft) of the soil surface, height growth decreases (35). Western hemlock is
poorly suited to sites where the water table is less than 15 cm (6 in)
below the soil surface (22). Although capable of existing on soils with
moisture regimes tending toward ustic or xeric, it grows poorly;
frequently, tops die back in years of drought.
The soil organic horizon under mature stands ranges from less than 7 to
more than 57 cm (2.8 to 22.5 in); the average depth increases from 11.4 cm
(4.5 in) on soils with good drainage to 43.2 cm (17.0 in) on poorly
drained soils (15). Commonly, the majority of roots, especially fine
roots, are concentrated just below the organic horizon. The importance of
the organic horizon as a continual supply of available nutrients for
western hemlock cannot be overstated. In coastal British Columbia,
earthworms are common in the organic horizons, even where the pH is less
than 4; earthworms may play an important role in making nutrients
available for root uptake. On many soils of Oregon and Washington,
however, rooting depths exceed 1 m (3.3 ft).
Soil reaction (pH) under stands containing western hemlock ranges from
less than 3.0 to nearly 6.0 in the organic horizons. The pH in the surface
mineral horizons ranges from 4.0 to 6.3 and that of the C horizon from 4.8
to 6.2 (21). Optimum range of pH for seedlings is 4.5 to 5.0.
Western hemlock is highly productive on soils with a broad range of
available nutrients. Evidence from various locations on the Pacific coast
suggests that the productivity of western hemlock increases as soil
nitrogen increases (15,21). There is no evidence that seedlings prefer
ammonium over nitrate ions (32). Phosphorus may be limiting on some sites
as suggested by data from Oregon showing a strong relation between site
index and soil phosphorus (21). Although the requirement of western
hemlock for cations is unclear, rooting habit and field data suggest that
it requires or tolerates considerable amounts of calcium.
The range in elevation at which western hemlock grows is broad, from sea
level to 2130 m (7,000 ft); its distribution varies by latitude and
mountain range. On the coast, western hemlock develops best between sea
level and 610 m (2,000 ft); in the Rocky Mountains, between 490 and 1280 m
(1,600 and 4,200 ft) (26).
Special Uses
(
英語
)
由Silvics of North America提供
The forest industry recognizes western hemlock as an all-purpose raw
material. It treats well and is used for pilings, poles, and railway ties.
Strength and nailing characteristics make it a preferred species for
construction lumber in North America and overseas. Better lumber grades
are used for appearance and remanufacture products. Western hemlock has
good-to-excellent pulping characteristics and is an important fiber source
for groundwood, thermomechanical, kraft, and sulfite pulps.
Vegetative Reproduction
(
英語
)
由Silvics of North America提供
Western hemlock can be propagated by
layering and from cuttings. Seedlings that die back to the soil surface
commonly sprout from buds near the root collar. Sprouting does not occur
from the roots or the base of larger saplings.
Western hemlock grafts readily. Incompatibility between the scion and
rootstock does not appear to be a problem. Growth of grafted material is
better than that of rooted material.
Brief Summary
(
英語
)
由Silvics of North America提供
Pinaceae -- Pine family
E. C. Packee
Western hemlock (Tsuga heterophylla), also called Pacific
hemlock and west coast hemlock, thrives in humid areas of the Pacific
coast and northern Rocky Mountains. Its potential for management as an
efficient producer of fiber has long been recognized. It is an important
browse species for deer and elk. Western hemlock provides an important
part of the esthetic background for eight national parks-four each in the
United States and Canada. It is a pioneer on many sites, yet it is
commonly the climax dominant. Although western hemlock grows like a weed,
its versatility and potential for management make it the "Cinderella
of the Northwest."
Distribution
(
英語
)
由Silvics of North America提供
Western hemlock is an important commercial tree species of the Pacific
coast and northern Rocky Mountains. Along the Pacific coast, its range
extends north along the Coast Ranges from central California to the Kenai
Peninsula in Alaska, a distance of 3200 km (2,000 mi) (11,18,33). It is
the dominant species in British Columbia and Alaska along the Coast
Mountains and on the coastal islands.
Inland it grows along the western and upper eastern slopes of the
Cascade Range in Oregon and Washington and the west side of the
Continental Divide of the northern Rocky Mountains in Montana and Idaho
north to Prince George, BC (7,18,26).
- The native range of western hemlock.
Physical Description
(
英語
)
由USDA PLANTS text提供
Tree, Evergreen, Monoecious, Habit erect, Trees without or rarely having knees, Tree with bark rough or scaly, Young shoots 3-dimensional, Buds not resinous, Leaves needle-like, Leaves alternate, Needle-like leaf margins finely serrulate (use magnification or slide your finger along the leaf), Leaf apex obtuse, Leaf apex mucronulate, Leaves < 5 cm long, Leaves < 10 cm long, Leaves yellow-green above, Leaves not blue-green, Needle-like leaves flat, Needle-like leaves not twisted, Needle-like leaf habit erect, Needle-like leaf habit drooping, Needle-like leaves per fascicle mostly 1, Needle-like leaf sheath early deciduous, Needle-like leaf sheath persistent, Twigs pubescent, Twigs not viscid, Twigs with peg-like projections or large fascicles after needles fall, Berry-like cones orange, Woody seed cones < 5 cm long, Bracts of seed cone included, Seeds brown, Seeds winged, Seeds unequally winged, Seed wings prominent, Seed wings equal to or broader than body.
- 編纂者
- Stephen C. Meyers
- 編纂者
- Aaron Liston
- 編纂者
- Steffi Ickert-Bond
- 編纂者
- Damon Little
Sbriwsen-hemlog y Gorllewin
(
威爾斯語
)
由wikipedia CY提供
Coeden fytholwyrdd sydd i'w chanfod yn Hemisffer y Gogledd yw Sbriwsen-hemlog y Gorllewin sy'n enw benywaidd. Mae'n perthyn i'r teulu Pinaceae. Yr enw gwyddonol (Lladin) yw Tsuga heterophylla a'r enw Saesneg yw Western hemlock-spruce.[1] Ceir enwau Cymraeg eraill ar y planhigyn hwn gan gynnwys Hemlog y Gorllewin.
Yn yr un teulu ceir y Sbriwsen, y binwydden, y llarwydden, cegid (hemlog) a'r gedrwydden. Mae'r dail (y nodwyddau) wedi'u gosod mewn sbeiral ac yn hir a phigog. Oddi fewn i'r moch coed benywaidd ceir hadau, ac maent yn eitha coediog ac yn fwy na'r rhai gwryw, sydd yn cwympo bron yn syth wedi'r peillio.
Gweler hefyd
Cyfeiriadau
Sbriwsen-hemlog y Gorllewin: Brief Summary
(
威爾斯語
)
由wikipedia CY提供
Coeden fytholwyrdd sydd i'w chanfod yn Hemisffer y Gogledd yw Sbriwsen-hemlog y Gorllewin sy'n enw benywaidd. Mae'n perthyn i'r teulu Pinaceae. Yr enw gwyddonol (Lladin) yw Tsuga heterophylla a'r enw Saesneg yw Western hemlock-spruce. Ceir enwau Cymraeg eraill ar y planhigyn hwn gan gynnwys Hemlog y Gorllewin.
Yn yr un teulu ceir y Sbriwsen, y binwydden, y llarwydden, cegid (hemlog) a'r gedrwydden. Mae'r dail (y nodwyddau) wedi'u gosod mewn sbeiral ac yn hir a phigog. Oddi fewn i'r moch coed benywaidd ceir hadau, ac maent yn eitha coediog ac yn fwy na'r rhai gwryw, sydd yn cwympo bron yn syth wedi'r peillio.
Jedlovec západní
(
捷克語
)
由wikipedia CZ提供
Jedlovec západní (Tsuga heterophylla) je druh jedlovce ze západního pobřeží severoamerického kontinentu, se severní hranicí výskytu na Kenajském poloostrově na Aljašce a jižní hranicí vyskytu na severu Kalifornie.
Domovina
Jedlovec západní je rozšířený druh v lesích západně od Pacifických pobřežních pohoří. Společně s mnohými dalšími jehličnany je v oblasti výskytu také důležitým stromem pro dřevozpracující průmysl.
![src=]()
Suché šišky jedlovce západního
Popis
Jedlovec západní je velký neopadavý jehličnatý strom, který je většinou 50-70 metrů vysoký, ale může dosáhnout výšky až 82 metrů s průměrem kmenu až 2,7 metru. Jedná se tedy o největší druh z rodu jedlovců; druhý největší jedlovec Mertensův dosahuje necelých 60 metrů. Borka je hnědá, tenká a vrásčitá. Koruna má uspořádaný široký kuželovitý tvar u mladých stromů, se zvyšujícím se věkem se stává válcovitou. Staré stromy mohou být bez větví v nejnižších třiceti až čtyřiceti metrech. V jakémkoli věku se dá poznat podle převislého cípu větévek. Výhonky jsou bledě žlutohnědé s bledým, jeden milimetr dlouhým ochmýřením. Listy jsou jehlicovité, 5-23 milimetrů dlouhé a kolem dvou milimetrů široké, na průřezu jsou velmi ploché se zubatým okrajem a prudkou špičkou. Na horní straně jsou tmavě zelené, na dolní straně mají dva význačné bílé pruhy průduchů, které jsou odděleny tenkou zelenou žilkou. Šišky jsou malé, zavěšené, lehce válcovité, 14-30 milimetrů dlouhé a 7-8 milimetrů široké, když jsou zavřené a 18-25 milimetrů široké, když jsou otevřené. Mají patnáct až dvacet pět 7-13 milimetrů dlouhé, tenké a ohebné šupiny. Nezralé šišky jsou zelené a dozrávají pět až sedm měsíců po opylení. Semena jsou hnědá, dva až tři milimetry dlouhá, s křehkým, sedm až devět milimetrů dlouhým bledě hnědým křidélkem.
Ekologie
Jedlovec západní je úzce spojen s deštnými pralesy mírného pásma, jejichž většina rozsahu se nachází do sta kilometrů od pobřeží Pacifiku. Nicméně existuje i vnitrozemská populace, a to ve Skalnatých horách v jihozápadní Britské Kolumbii, severním Idahu a západní Montaně. Většinou se vyskytuje v nadmořských výškách do 600 metrů, vnitrozemská populace však dosahuje až 1800 metrů nad mořem.
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Deska v lesním parku ve washingtonském
Everettu dokazující, že se jedná o státní strom Washingtonu.
Stínová tolerance
Jedlovec západní je druh, který hodně toleruje stín; mezi stromy severozápadu USA se mu mohou vyrovnat pouze tis západoamerický a jedle líbezná. Mladé stromy většinou rostou pod korunovými klenbami jiných jehličnanů, například smrku sitka a douglasky, kde čekají dlouhá léta, než mohou využít mezery mezi klenbami. Poté mohou tyto jehličnany zastínit a případně i vytlačit. Bouře a požáry mohou však ostatním stromům dodat dostatek místa k regeneraci.
Růst
Prvotní růst je pomalý, po jednom roce dospěje semenáček do výšky tří až pěti centimetrů a v dalším roce vyroste na deset až dvacet centimetrů. Po zavedení se mladé stromy pod úplným slunečním zářením každý rok zvětší o 50-120 centimerů (vzácně až 140), než dospějí výšky dvaceti až třiceti metrů. Do výšky čtyřiceti až padesáti metrů pokračují ve svém růstu rychlostí 30-40 cm ročně. Nejvyšší exemplář, který dorostl do 82 metrů, je k nalezení ve státním parku Redwood National and State Parks v Kalifornii, kde jsou k vidění prastaré, až 1 200 let staré stromy.
Použití
Jedlovec západní je státním stromem státu Washington.
Kultivace
Strom je pěstován jako okrasná rostlina v zahradách ve svém přirozeném prostředí a při pobřeží Tichého oceánu, kde je nejspolehlivější ve vlhčích oblastech. V sušších oblastech, jako je například Victoria v Britské Kolumbii, má náročné půdní podmínky. Ve vlhkých a kyselých půdách potřebuje organické hnojivo.
Lesnictví
Mimo svou oblast přirozeného výskytu má význam v lesnictví a papírnictví a jako okrasná rostlina ve velkých zahradách severozápadní Evropy a jižního Nového Zélandu.
Ve Velké Británii a na Novém Zélandu zdomácněl, není ale považován za invazivní druh.
Další využití
Jedlé kambium může být sbíráno zpracováním kůry stromu. Výsledný produkt může být požíván ihned, nebo může být usušen a uchováván. Jemné nové jehličky mohou být žvýkány nebo použity do hořkého čaje, který má potom větší obsah vitamínu C.
Kůra má také své využití ve vydělávání kůže.
Větve jedlovce západního jsou užívány k zachycení a kulinářské přípravě sledích jiker v době jarního tření na jihovýchodní Aljašce. Kromě snadného zachycení přispívají k daleko výraznější chuti. Tato technika byla převzata z tradičních sběračských technik původních obyvatel Aljašky, zejména kmene Tlingitů.
Reference
V tomto článku byl použit překlad textu z článku Tsuga heterophylla na anglické Wikipedii.
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↑ Červený seznam IUCN 2018.1. 5. července 2018. Dostupné online. [cit. 2018-08-11]
Jedlovec západní: Brief Summary
(
捷克語
)
由wikipedia CZ提供
Jedlovec západní (Tsuga heterophylla) je druh jedlovce ze západního pobřeží severoamerického kontinentu, se severní hranicí výskytu na Kenajském poloostrově na Aljašce a jižní hranicí vyskytu na severu Kalifornie.
Vestamerikansk hemlock
(
丹麥語
)
由wikipedia DA提供
Vestamerikansk hemlock er et stort, stedsegrønt nåletræ med en kegleformet krone. Nålene har forskellig længde, og koglerne er små og lysebrune. Træet er fuldt hårdført og bruges en del i større haver og parker.
Kendetegn
Vestamerikansk hemlock er et stort, stedsegrønt nåletræ. Kronen er længe kegleformet med en hængende top. Senere bliver den mere bred og cylindrisk. Grenene sidder med stor afstand og er overhængende med nedadvendte spidser. Barken er først tofarvet: lysebrun på lyssiden og lysegrøn på skyggesiden. Skuddet er desuden ribbet med beigefarvede hår. Knopperne er brune (men meget lyse i løvspringet), små og runde. Nålene sidder i to rækker, og de har de forskellig længde og aftagende bredde frem mod en afrundet spids. Nålene er først matgrønne, men får senere mørkegrønne oversider og undersider med to hvide striber. Hanblomsterne sidder samlet i stande inde mellem nålene, mens de hunlige sidder for enden af særlige skud. Frugterne er kogler, der først er lysegrønne til violette, men lysebrune ved modning.
Rodsystemet er højtliggende og består mest af fine, trævlede rødder[1]
I hjemlandet når arten højder på ca. 70 m og kronebredder nær 25 m. I Europa får udvoksede træer sjældent størrelser over 25 x 12 m henholdsvis.
Hjemsted
Vestamerikansk hemlock har sin naturlige udbredelse langs den amerikanske stillehavskyst, fra Californien over Oregon og Washington og British Columbia til Alaska. Her er træet én af de dominerende arter i de blandede nåleskove, der er opstået i de regnrige bjerge, hvor jorden er forholdsvis næringsrig og veldrænet.
I Olympic National Park, som ligger på Olympic-halvøen vest for Seattle, Washington, USA, findes nogle skove i lavlandet og på dalbunden mellem bjergene, hvor denne art vokser sammen med bl.a. almindelig linnæa, amerikansk skovstjerne, broget skumspiræa, busket bjergte, bølle (flere arter), druehyld, grøn douglasgran, kæmpethuja, kæmpegran, sitkagran, småhjerte, sværdbregne, Trillium ovatum (en art af treblad) og vestamerikansk mahonie[2]
Note
Vestamerikansk hemlock: Brief Summary
(
丹麥語
)
由wikipedia DA提供
Vestamerikansk hemlock er et stort, stedsegrønt nåletræ med en kegleformet krone. Nålene har forskellig længde, og koglerne er små og lysebrune. Træet er fuldt hårdført og bruges en del i større haver og parker.
Westamerikanische Hemlocktanne
(
德語
)
由wikipedia DE提供
Die Westamerikanische Hemlocktanne (Tsuga heterophylla), auch Westliche Hemlock genannt, ist eine Pflanzenart aus der Gattung Hemlocktannen (Tsuga) in der Familie der Kieferngewächse (Pinaceae).
Verbreitung
Die Westliche Hemlocktanne stammt von der Westküste Nordamerikas und ist dort von Alaska bis zum nördlichen Kalifornien verbreitet. Sie ist in Mitteleuropa winterhart und wird hier im forstlichen Versuchsanbau angepflanzt.
Die Westamerikanische Hemlocktanne ist der "Staatsbaum" des US-Bundesstaates Washington.
Beschreibung
Die Westliche Hemlocktanne ist die größte der Hemlocktannen-Arten. Sie ist ein immergrüner Baum. In den bevorzugten Lagen ihres Verbreitungsgebietes, im Olympic-Gebirge, erreicht sie Wuchshöhen über 70 Meter. Auf den britischen Inseln erreicht sie immerhin noch 50 Meter Wuchshöhe. Auf bevorzugten Böden ist die Westliche Hemlocktanne sehr raschwüchsig und erreicht einen Jahreszuwachs von über 1 Meter. Die Baumkrone ist kegelförmig und beim jungen Baum schmal, im Alter breiter werdend. Der Leittrieb ist deutlich überhängend. Die Borke ist graubraun. Die Rinde der Zweige ist gelbbraun und fein behaart. Die Nadeln sind beiderseits des Zweiges gescheitelt; sie sind in der oberen Reihe etwa 0,6 cm, in der unteren Reihe dagegen 1,5 bis 1,8 cm lang. Diese Verschiedenartigkeit der Nadeln begründet den wissenschaftlichen Artnamen heterophylla. Die Nadeln sind zunächst frischgrün und matt, später dunkelgrün und glänzend.
Die Westamerikanische Hemlocktanne ist einhäusig getrenntgeschlechtig (monözisch). Die Zapfen sind 2 bis 3 cm lang und stumpf eiförmig.
Die Chromosomenzahl beträgt 2n = 24.[1]
Taxonomie
Tsuga heterophylla (Raf.) Sarg. hat folgende Synonyme: Abies heterophylla Raf., Abies microphylla Raf., Tsuga albertiana (A.Murray bis) Sénécl., Pinus pattoniana W.R.McNab.[2]
Verwendung
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gemessertes Furnier, geölt, ungeschliffen
Die Westamerikanische Hemlocktanne liefert ein hellbraunes Holz mit geradem Faserverlauf und ebenmäßiger Struktur. Die Jahresringe treten nicht so deutlich hervor wie bei der Kanadischen Tsuga, die zur selben Gattung gehört. Das Holz trocknet sehr langsam, so dass Trocknungsschäden leicht eintreten können. Getrocknetes Holz ist allerdings sehr standfest. Es ist eines der leichtesten Nadelhölzer im Handel und gilt als widerstandsfähiger als das Holz der Fichte. Sie wird unter anderem als Bauholz, für Kisten, Sperrholz und zur Papierverarbeitung verwendet.[3]
Quellen
-
Christopher J. Earle: Tsuga heterophylla. In: The Gymnosperm Database. 20. März 2011, abgerufen am 20. Oktober 2011 (englisch, Abschnitt Beschreibung).
Einzelnachweise
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↑ Tropicos. [1]
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↑ Rafaël Govaerts (Hrsg.): Tsuga. In: World Checklist of Selected Plant Families (WCSP) – The Board of Trustees of the Royal Botanic Gardens, Kew, abgerufen am 11. April 2019.
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↑ Andrew Duncan, Gwen Rigby: Der Hobbytischler – Technik der Holzverarbeitung, Deutsche Ausgabe in Zusammenarbeit mit der Meisterschule Ebern für das Schreinerhandwerk, Orbis Verlag, München 1984, ISBN 3-572-00763-1, S. 197
Weblinks
– Album mit Bildern, Videos und Audiodateien
Westamerikanische Hemlocktanne: Brief Summary
(
德語
)
由wikipedia DE提供
![src=]()
Tsuga heterophylla
![src=]()
Tsuga heterophylla
Die Westamerikanische Hemlocktanne (Tsuga heterophylla), auch Westliche Hemlock genannt, ist eine Pflanzenart aus der Gattung Hemlocktannen (Tsuga) in der Familie der Kieferngewächse (Pinaceae).
Tsuga heterophylla
(
英語
)
由wikipedia EN提供
Tsuga heterophylla, the western hemlock[2] or western hemlock-spruce,[3] is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Sonoma County, California.[4][5] The Latin species name means 'variable leaves'.[6]
Description
Western hemlock is a large evergreen conifer growing to 50–70 metres (165–230 feet) tall, exceptionally 83 m (273 ft),[7] and with a trunk diameter of up to 2.7 m (9 ft). It is the largest species of hemlock, with the next largest (mountain hemlock) reaching a maximum height of 59 m (194 ft). The bark is brown, thin, and furrowed (outwardly appearing similar to that of Douglas-fir).[6] The crown is a very neat broad conic shape in young trees with a strongly drooping lead shoot, becoming cylindrical in older trees, which may have no branches in the lowest 30–40 m (100–130 ft). At all ages, it is readily distinguished by the pendulous branchlet tips. The shoots are very pale buff-brown, almost white, with pale pubescence about 1 millimetre (1⁄32 in) long.
The leaves are needle-like, 5–23 mm (3⁄16–29⁄32 in) long and 1.5–2 mm (1⁄16–3⁄32 in) broad, strongly flattened in cross-section, with a finely serrated margin and a bluntly acute apex. They are mid to dark green above; the underside has two distinctive white bands of stomata with only a narrow green midrib between the bands. They are arranged spirally on the shoots but are twisted at the base to lie in two ranks on either side of the shoot. The cones appear on trees over about 25 years old;[6] they are small, pendulous, slenderly cylindrical, 14–30 mm (9⁄16–1+3⁄16 in) long and 7–8 mm (9⁄32–5⁄16 in) broad when closed, opening to 18–25 mm (23⁄32–31⁄32 in) broad. They have 15–25 thin, flexible scales 7–13 mm (9⁄32–1⁄2 in) long. The immature cones are green, maturing gray-brown 5–7 months after pollination. They are usually plentiful enough to cover the ground beneath the tree.[6] The abundant seeds are brown, 2–3 mm (3⁄32–1⁄8 in) long, with a slender, pale-brown wing measuring 7–9 mm (9⁄32–11⁄32 in) long.[4][5][6]
Initial growth is slow; one-year-old seedlings are commonly only 3–5 centimetres (1+1⁄8–2 in) tall, and two-year-old seedlings 10–20 cm (4–8 in) tall. Once established, saplings in full light may have an average growth rate of 50–120 cm (20–47 in) (rarely 140 cm, 55 in) annually until they are 20–30 m (65–100 ft) tall, and in good conditions still 30–40 cm (12–16 in) annually when 40–50 m (130–165 ft) tall. The tallest specimen, 82.83 m (271 ft 9 in) tall, is in Prairie Creek Redwoods State Park, California (United States). The species is long-lived, especially at higher elevations,[6] with trees over 1,200 years old known.[5]
Branch with mature seed cones that have released their seeds
Habitat and ecology
T. heterophylla is an integral component of Pacific Northwest forests west of the Coast Ranges, where it is a climax species. It is also an important timber tree throughout the region, along with many of its large coniferous associates.[8] The species is closely associated with temperate rainforests, and most of its range is less than 100 kilometres (62 miles) from the Pacific Ocean. Valleys it can be found in usually receive at least 80 centimetres (31 inches) of rain annually.[6] It mostly grows at low altitudes, from sea level to 600 m (2,000 ft). In western Washington, it can be found up to elevations of 1,070 m (3,510 ft).[6] The species can also be found in humid areas of mountains further inland, where western white pine is normally dominant.[6] For example, in the Columbia Mountains in and around southeastern British Columbia and northern Idaho, it grows up to 1,500 m (4,900 ft), particularly on north-facing slopes.[6] In the interior part of its range in Idaho, it can be found up to 1,800 m (5,900 ft).[4][5]
Western hemlock is a very shade-tolerant tree; among associated species in the Pacific Northwest, it is matched or exceeded in shade tolerance only by Pacific yew and Pacific silver fir.[8] Young plants typically grow up under the canopy of other conifers such as Sitka spruce or Douglas-fir, where they can persist for decades waiting to exploit a gap in the canopy. They eventually replace these conifers, which are relatively shade-intolerant, in climax forest. However, storms and wildfires will create larger openings in the forest where these other species can then regenerate. Its thin bark and shallow roots makes it susceptible to fire.[6] At higher elevations, the species can be found mingling with T. mertensiana (mountain hemlock), seeming to take on some of its characteristics although there is no hard evidence of hybridization.[6]
Western hemlock forms ectomycorrhizal associations with some well-known edible fungi such as chanterelles (Cantharellus formosus, C. subalbidus, and Craterellus tubaeformis).[9][10] It is capable of associating with wood-decay fungi in addition to soil fungi; this enables its seedlings to survive on rotting stumps and logs.[11] Older forests are damaged by rot-causing fungi, dwarf mistletoe, and leaf-consuming insects such as Acleris gloverana and Lambdina fiscellaria.[6]
Uses
The bark has long served as a source of tannin for tanning leather.[6]
Cultivation
Western hemlock is cultivated as an ornamental tree in gardens in its native habitats and along the U.S. Pacific Coast, where its best reliability is seen in wetter regions. In relatively dry areas, as at Victoria, British Columbia, it is exacting about soil conditions. It needs a high level of organic matter (well-rotted wood from an old log or stump is best; animal manures may have too much nitrogen and salt), in a moist, acidic soil. It is also cultivated in temperate regions worldwide. It has gained the Royal Horticultural Society's Award of Garden Merit.[12][13]
It can also be found in large gardens in northwest Europe and southern New Zealand.
Forestry
When planted on the banks of a river, western hemlock can help reduce erosion. Outside of its natural range, the tree is of importance in forestry.
Until the early 1920s, the tree was largely ignored for use as lumber due to its presumed similarity to the poor-quality eastern hemlock.[6] Since then, it has been greatly utilized for timber (as a softwood) and paper production;[6] it is used for making doors, joinery, and furniture.[14] Its fiber is used to make rayon and various plastics.[6]
It has naturalised in some parts of Great Britain and New Zealand—not so extensively as to be considered an invasive species, but as an introduced one.
Food and medicine
The edible cambium can be collected by scraping slabs of removed bark. The resulting shavings can be eaten immediately, or can be dried and pressed into bread, as was done by the natives of Southeast Alaska.[15] The inner bark was eaten by some Native American tribes as an emergency food, and the bark was cooked to make medicinal extracts for tuberculosis, rheumatic fever, and hemorrhage.[6] The bark could also be boiled to make dark red dyes to make fishing nets and lines less visible to fish.[6]
Western hemlocks have been submerged to collect herring eggs[6] during the spring spawn in southeast Alaska. The boughs provide an easily collectible surface for the eggs to attach to[6] as well as providing a distinctive taste. This practice originates from traditional gathering methods used by Native Alaskans from southeast Alaska, specifically the Tlingit people.
Tender new-growth needles can be chewed directly or made into a bitter tea, rich in vitamin C (similar to some other hemlock and pine species).
Culture
Western hemlock is the state tree of Washington.[16]
References
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^ Farjon, A. (2013). "Tsuga heterophylla". IUCN Red List of Threatened Species. 2013: e.T42435A2980087. doi:10.2305/IUCN.UK.2013-1.RLTS.T42435A2980087.en. Retrieved 19 November 2021.
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^ USDA, NRCS (n.d.). "Tsuga heterophylla". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 12 December 2015.
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^ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 26 June 2015. Retrieved 17 October 2014.
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^ a b c Farjon, A. (1990). Pinaceae. Drawings and Descriptions of the Genera. Koeltz Scientific Books ISBN 3-87429-298-3.
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^ a b c d Gymnosperm Database: Tsuga heterophylla Archived 2005-09-24 at the Wayback Machine
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^ a b c d e f g h i j k l m n o p q r s t u Arno, Stephen F.; Hammerly, Ramona P. (2020) [1977]. Northwest Trees: Identifying & Understanding the Region's Native Trees (field guide ed.). Seattle: Mountaineers Books. pp. 110–117. ISBN 978-1-68051-329-5. OCLC 1141235469.
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^ Tallest Hemlock, M. D. Vaden, Arborist: Tallest known Hemlock, Tsuga heterophylla
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^ a b Packee, E.C. (1990). "Tsuga heterophylla". In Burns, Russell M.; Honkala, Barbara H. (eds.). Conifers. Silvics of North America. Washington, D.C.: United States Forest Service (USFS), United States Department of Agriculture (USDA). Vol. 1 – via Southern Research Station.
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^ Dunham, Susie M.; O'Dell, Thomas E.; Molina, Randy (2006). "Forest stand age and the occurrence of chanterelle (Cantharellus) species in Oregon's central Cascade Mountains" (PDF). Mycological Research. 110 (12): 1433–40. doi:10.1016/j.mycres.2006.09.007. PMID 17123812. Archived from the original (PDF) on 14 August 2011.
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^ Trappe, MJ (May–June 2004). "Habitat and host associations of Craterellus tubaeformis in northwestern Oregon". Mycologia. 96 (3): 498–509. doi:10.2307/3762170. JSTOR 3762170. PMID 21148873.
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^ "Fungi from decayed wood as ectomycorrhizal symbionts of western hemlock". Archived from the original on 13 March 2018.
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^ "RHS Plant Selector – Tsuga heterophylla". RHS. Retrieved 5 March 2021.
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^ "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 103. Retrieved 27 December 2018.
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^ Buckley, Michael (2005). "A basic guide to softwoods and hardwoods" (PDF). worldhardwoods.com. Retrieved 1 October 2017.
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^ Whitney, Stephen (1985). Western Forests (The Audubon Society Nature Guides). New York: Knopf. p. 416. ISBN 0-394-73127-1.
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^ "State Symbols". Washington State Government. Archived from the original on 15 November 2007. Retrieved 20 February 2022.
Tsuga heterophylla: Brief Summary
(
英語
)
由wikipedia EN提供
Tsuga heterophylla, the western hemlock or western hemlock-spruce, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Sonoma County, California. The Latin species name means 'variable leaves'.
Okcidenta cugo
(
世界語
)
由wikipedia EO提供
La okcidenta cugo (Tsuga heterophylla), estas arbospecio hejma ĉe la okcidenta marbordo de Nordameriko, kun sia nordokcidena limo en Kenaj-Duoninsulo, Alasko, kaj sia sudorienta limo en norda Kantono Sonoma, Kalifornio[2][3].
Biotopo
Tiu nearktisa cugospecio estas grava komponanto de la Pacifik-Nordokcidentaj Arbaroj de la Pacifikaj Marbordaj Montaroj, kie ĝi estas specio el la klimaksa vegetaĵaro. Ĝi ankaŭ estas grava arbo por konstruligno tra la regiono, kune kun pluraj de siaj grandaj koniferaj socianoj [4].
Priskribo
La okcidenta cugo estas granda ĉiamverda konifera arbo kiu altas ĝis 50–70 m, escepte 78 m, kaj kun trunka diametro ĝis 2,7 m. Ĝis estas la plej granda cugospecio, kun la dua plej granda, Montara cugo (T. mertensiana) kiu atingas maksimumon de 59 m. La arboŝelo estas bruna, maldika kaj sulkigita. La arbokrono estas tre nete larĝ-konusa ĉe junaj arboj kun forte pendanta pintoŝoso, estiĝante cilindra ĉe pli maljunaj arboj; maljunaj arboj povas esti senbranĉaj je la plej malaltaj 30–40 m. Je ĉiuj aĝoj, ĝi estas facile distingebla per la pendantaj branĉetaj pintoj. La ŝosoj estas tre pale flav-brunaj, preskaŭ blankaj, kun malhela haraĵo kiu longas ĉirkaŭ 1 mm. La folioj estas pinglecaj; ili longas 5–23 mm kaj larĝas 1,5–2 mm, kaj transvers-tranĉe estas forte platigitaj, kun fajne segita rando kaj senpinte akra apekso. Ili estas meze ĝis malhele verdaj supre; la suba flanko havas du diferencajn blankajn striojn de stomoj kun nur mallarĝa verda mezripo inter la strioj. Ili estas spirale aranĝitaj sur la ŝosoj sed estas turnigitaj je la bazo por troviĝi en du vicoj ambaŭflanke de la ŝoso. La strobiloj estas etaj, pendantaj, svelte cilindraj, 14–30 mm longaj kaj 7–8 mm larĝaj kiam fermitaj, malfermante ĝis larĝeco de 18–25 mm. Ili havas 15–25 maldikajn, fleksiĝemajn skvamojn kiuj longas 7–13 mm. La nematuraj strobiloj estas verdaj, maturante griz-brunaj 5–7 monatoj post polenado. La semoj estas brunaj, longas 2–3 mm, kun svelte, 7–9 mm longa pale bruna flugilo [2][3].
Ekologio
La okcidenta cugo estas intense asociata kun la Pacifikaj moderaj pluvarbaroj, kaj plimulto de sia arealo troviĝas malpli ol 100 km ekde la Pacifika oceano. Tamen ekzistas landinterna populacio en Rokmontaro en sudorienta Brita Kolumbio, norda Idaho kaj okcidenta Montano. Ĝi plejofte vegetas je malaltaj altitudoj, ekde marnivelo ĝis 600 m, sed ĝis 1 800 m en la landinterna parto de la arealo en Idaho [2][3].
Ombro-toleremo
Ĝi estas tre ombro-tolerema arbo; inter asociataj specioj en la Pacifika Nordokcidento, ĝi nur estas egalata aŭ superata pri ombro-toleremo de la pacifika taksuso (Taxus brevifolia) kaj de la gracia abio (Abies amabilis) [4]. Junaj plantoj tipe elkreskas sub la kanopeo de aliaj koniferoj kiel Sitka-piceo kaj Menzies-pseŭdocugo, kie ili povas postvivi dum dekaj da jaroj atendante aperturon en la kanopeo. Eventuale ili anstataŭas tiujn koniferojn, kiuj estas relative ombro-netoleremaj, en klimaksan arbaron. Tamen, ventegoj kaj arbaraj incendioj faros pli grandajn aperturojn en la arbaro kie tiuj aliaj specioj povas rejuniĝi.
Komenca kreskado malrapidas; plantoj de unu jaro komune nur altas 3–5 cm, kaj plantoj de du jaroj altas 10–20 cm. Iam starigintaj, arbidoj en plena lumo povas havi averaĝan jaran alkreskon de 50–120 cm (malofte 140 cm) ĝis ili altas 20–30 m, kaj en bonaj cirkonstancoj jare ankoraŭ 30–40 cm kiam ili altas 40–50 m. La plej granda specimeno altas 78,9 m, troviĝante en Sekvojara Nacia Parko Prairie Creek, Kalifornio. Okcidenta cugo longdaŭre viveblas, kaj oni scias pli ol 1 200-jarajn arbojn [3].
Uzado
La okcidenta cugo estas la subŝtata arbo de Vaŝingtonio [5].
Kultivado
La okcidenta cugo estas kultivata kiel ornama arbo en ĝardenoj en sia hejma arealo kaj laŭlonge de la usona pacifika marbordo, kie ĝi plej bone prosperas en la pli humidaj regionoj. En relative sekaj areoj, kiel en Viktorio (Brita Kolumbio), ĝi estas postulema koncerne grundaj cirkonstancoj. Ĝi bezonas altan nivelon de organa materialo ( bone putriĝinta ligno el maljuna arbo estas plej bone; stala sterko povas enteni tro da nitrogeno kaj salo), en humida, acida grundo.
Forstado
Ekstere de sia hejma arealo, okcidenta cugo estas grava en forstumado por produktado de konstruligno kaj papero, kaj kiel ornama arbo en grandaj ĝardenoj, en nordokcidenta Eŭropo kaj suda Nova-Zelando.
Ĝi estas naturalizita en iuj partoj de Britujo kaj Nova-Zelando, ne tiel etendiĝante por esti konsiderata kiel invada specio, sed kiel enmetita specio.
Nutraĵo
La manĝebla kambiumo povas esti kolektita apartigante bendojn de forigita arboŝelo. La rezultantaj deskrapaĵoj estas tuje manĝeblaj, aŭ ili estas sekigendaj kaj kunpremendaj por konservi ilin. La arboŝelo ankaŭ servas kiel resurcon de tanino por tanado.
Malmolaj novaj pingloj (folioj) estas senpere maĉeblaj aŭ uzeblaj en amaran teon, riĉan je vitamino C (simile kiel por iuj aliaj cugaj kaj pinaj specioj).
La okcident-cugaj branĉoj estas uzataj por kolekti haringajn ovojn dum la printempa frajado en sudorienta Alasko. La branĉoj provizas per facile kolektada surfaco por la algluiĝo de la ovoj kune kun speciala gusto. Tiu praktiko originas de tradiciaj kolektadaj metodoj de la alaskaj indiĝenaj popoloj, speciale de la Tlingitoj.
Vidu ankaŭ
- Arbaroj de centra kaj suda Kaskada Montaro
- Arbaroj de norda-centra Rokmontaro
- Centra-pacifikaj marbordaj arbaroj
- Ĉina cugo
- Orienta cugo
Referencoj
-
↑ angle Conifer Specialist Group (1998). Tsuga heterophylla. Internacia Ruĝa Listo de Endanĝeritaj Specioj, eldono de 2006. IUCN 2006. Elŝutita 12 May 2006.
- ↑ 2,0 2,1 2,2 angle Farjon, A. (1990). Pinaceae. Drawings and Descriptions of the Genera. Koeltz Scientific Books ISBN 3-87429-298-3.
- ↑ 3,0 3,1 3,2 3,3 angle Gymnosperm Database: Tsuga heterophylla
- ↑ 4,0 4,1 angle Packee, E.C. Tsuga heterophylla. Silvics of North America, Volume 1. U.S. Department of Agriculture, Forest Service, Washington, DC. 1990. Tsuga heterophylla angle
-
↑ angle Washington State Government: State Symbols
Okcidenta cugo: Brief Summary
(
世界語
)
由wikipedia EO提供
La okcidenta cugo (Tsuga heterophylla), estas arbospecio hejma ĉe la okcidenta marbordo de Nordameriko, kun sia nordokcidena limo en Kenaj-Duoninsulo, Alasko, kaj sia sudorienta limo en norda Kantono Sonoma, Kalifornio.
Tsuga heterophylla
(
西班牙、卡斯蒂利亞西班牙語
)
由wikipedia ES提供
Tsuga heterophylla, la tsuga del Pacífico,[2] tsuga heterófila, también tsuga de Alberta,[3] es una especie arbórea, originaria del noroeste de Norteamérica. Su límite noroeste se encuentra en la península de Kenai, Alaska, y su límite sureste, en el norte del Condado de Sonoma, California.[4][5]
Descripción
Es una gran conífera de hoja perenne que crece hasta 50-70 m de altura, y excepcionalmente llega a 78 m. Es un poco más alta que una especie parecida, la tsuga de Canadá. El diámetro del tronco alcanza 2,7 m. La corteza es de color marrón, delgada y con surcos.
Está estrechamente asociada con los bosque templado de frondosas. La mayoría se encuentra a menos de 100 km del Océano Pacífico. Sin embargo existen poblaciones en el interior de las Montañas Rocosas, en el sureste de la Columbia Británica, el norte de Idaho y Montana occidental. Crece sobre todo a baja altura, desde el nivel del mar hasta los 600 msnm, pero llega hasta los 1.800 msnm en su área de distribución en Idaho.
Fuera de su área nativa, tiene importancia para la silvicultura y la producción de papel, así como árbol ornamental en grandes jardines, en el noroeste de Europa y el sur de Nueva Zelanda.
Taxonomía
Tsuga heterophylla fue descrita por (Raf.) Sarg. y publicado en The Silva of North America 12: 73. 1898.[6]
- Etimología
Tsuga: nombre genérico que es el nombre vernáculo en Japón para la especie Tsuga sieboldii.
heterophylla: epíteto latíno que significa "con hojas diferentes".[7]
- Sinonimia
-
Abies albertiana A.Murray bis
-
Abies bridgesii Kellogg
-
Abies heterophylla Raf.
-
Abies microphylla Raf.
-
Pinus pattoniana W.R.McNab
-
Tsuga albertiana (A.Murray bis) Sénécl.[8]
Referencias
-
↑ Conifer Specialist Group (1998). «Tsuga heterophylla». Lista Roja de especies amenazadas de la UICN 2006 (en inglés). ISSN 2307-8235. Consultado el 12 de mayo de 2006.
-
↑ Nombre vulgar preferido en castellano, en Árboles: guía de campo; Johnson, Owen y More, David; traductor: Pijoan Rotger, Manuel, ed. Omega, 2006. ISBN 978-84-282-1400-1. Versión en español de la Collins Tree Guide.
-
↑ Tsuga heterófila, tsuga del Pacífico, tsuga de Alberta, Tsuga heterophylla Sarg, pág. 20 - Gregor Aas y Andreas Riedmiller: Gran Guía de la Naturaleza, editorial Everest, traductor Eladio M. Bernaldo de Quirós, ISBN 84-241.2663.5, 4.ª edición, 1993.
-
↑ Farjon, A. (1990). Pinaceae. Drawings and Descriptions of the Genera. Koeltz Scientific Books ISBN 3-87429-298-3.
-
↑ Gymnosperm Database: Tsuga heterophylla
-
↑ «Tsuga heterophylla». Tropicos.org. Missouri Botanical Garden. Consultado el 12 de diciembre de 2013.
-
↑ En Epítetos Botánicos
-
↑ Tsuga heterophylla en PlantList
Bibliografía
- Abrams, L. 1923. Ferns to Birthworts. 1: 1–557. In L. Abrams (ed.) Ill. Fl. Pacific States. Stanford University Press, Stanford.
- Cody, W. J. 1996. Fl. Yukon Terr. i–xvii, 1–669. NRC Research Press, Ottawa.
- Flora of North America Editorial Committee, e. 1993. Pteridophytes and Gymnosperms. Fl. N. Amer. 2: i–xvi, 1–475.
- Hitchcock, C. H., A.J. Cronquist, F. M. Ownbey & J. W. Thompson. 1969. Vascular Cryptogams, Gymnosperms, and Monocotyledons. 1: 1–914. In C. L. Hitchcock Vasc. Pl. Pacif. N.W.. University of Washington Press, Seattle.
- Hultén, E. 1968. Fl. Alaska i–xxi, 1–1008. Stanford University Press, Stanford.
- Jepson, W. L. 1909. Fl. Calif. vol. 1. 578 pp. Cunningham, Curtiss & Welch, San Francisco.
- Moss, E. H. 1983. Fl. Alberta (ed. 2) i–xii, 1–687. University of Toronto Press, Toronto.
- Munz, P. A. & D. D. Keck. 1959. Cal. Fl. 1–1681. University of California Press, Berkeley.
- Scoggan, H. J. 1978 [1979]. Pteridophyta, Gymnospermae, Monocotyledoneae. 2: 93–545. In Fl. Canada. National Museums of Canada, Ottawa.
- Welsh, S. L. 1974. Anderson's Fl. Alaska Adj. Parts Canada i–xvi, 1–724. Brigham Young University Press, Provo.
Tsuga heterophylla: Brief Summary
(
西班牙、卡斯蒂利亞西班牙語
)
由wikipedia ES提供
![src=]()
Tsuga heterophylla
Tsuga heterophylla, la tsuga del Pacífico, tsuga heterófila, también tsuga de Alberta, es una especie arbórea, originaria del noroeste de Norteamérica. Su límite noroeste se encuentra en la península de Kenai, Alaska, y su límite sureste, en el norte del Condado de Sonoma, California.
![src=]()
Árbol joven.
Läänetsuuga
(
愛沙尼亞語
)
由wikipedia ET提供
Läänetsuuga (Tsuga heterophylla) on igihaljas okaspuuliik männiliste sugukonnast tsuuga perekonnast.
Kirjeldus
Läänetsuuga kasvab Põhja-Ameerika loodeosa mägedes, enamasti kuni 100 km kaugusel Vaiksest ookeanist; valdavalt kuni 600 meetri kõrgusel merepinnast. Esineb ka Kaljumäestiku läänenõlvadel ning Kanadas Briti Columbias.
Puu võib kasvada 30...80 meetri kõrguseks. Võra on tihe, lai ja koonusjas, ulatub sageli peaaegu maani. Vanematel puudel võib tüve alumine 30...40 meetrit laasuda. Tihedad oksad on horisontaalsed ja veidi tõusvad, tipust longus. Tüvi on sirge; selle läbimõõt võib ulatuda 2,7 meetrini. Koor on tumepruun ja õhuke. Võrsed on heledad, kaetud umbes 1 mm pikkuste karvakestega. Pungad on ümarad ja karvased. Lapikud okkad on 5...23 mm pikkused ja 1,5...2 mm laiused; tumerohelised ja läikivad, harvade väikeste sakkidega, otsast tömpteravad. Käbid on rippuvad, piklikovaalsed, 14...30 mm pikkused; läbimõõt on suletuna 7...8 mm, avatuna 18...25 mm.
Noorena on puu kasv aeglane. Läänetsuuga eelistab pool- või täisvarju. Kasvab meelsasti teiste okaspuude varjus. Läänetsuuga on pikaealine; teada on üle 1200 aasta vanuseid isendeid.
Kasutamine
Läänetsuugat kasvatatakse ka aia- ja pargipuuna muu hulgas Euroopas ja Uus-Meremaal. Eesti kliimas on noorena külmaõrn ega kannata talviseid tuuli. Eestis kasvab põõsasjalt või väikese puuna. Euroopasse toodi läänetsuuga 1860. aastal. Suurbritannias ja Uus-Meremaal on puu kohati naturaliseerunud.
Läänetsuugalt saadakse väärtuslikku tarbepuitu.
Viited
Välislingid
Läänetsuuga: Brief Summary
(
愛沙尼亞語
)
由wikipedia ET提供
Läänetsuuga (Tsuga heterophylla) on igihaljas okaspuuliik männiliste sugukonnast tsuuga perekonnast.
Lännenhemlokki
(
芬蘭語
)
由wikipedia FI提供
Lännenhemlokki (Tsuga heterophylla) on mäntykasvien (Pinaceae) heimoon kuuluva havupuu. Se kasvaa luonnonvaraisena Pohjois-Amerikan länsirannikolla. Lännenhemlokki on suurimmaksi kasvava laji hemlokkien suvussa ja voi saavuttaa 50–70 metrin pituuden ja 2,7 metrin rungonpaksuuden. Laji on Länsi-Kanadassa tärkeä metsätalouspuu.[2]
Lännenhemlokkia on Suomessa koeviljelty arboretumeissa ja kasvitieteellisissä puutarhoissa. Mustilan arboretumissa Elimäellä on yli 60-vuotias ja 25 metriä korkea lännenhemlokkimetsä.[3]
Lähteet
Lännenhemlokki: Brief Summary
(
芬蘭語
)
由wikipedia FI提供
![src=]()
Tsuga heterophylla
![src=]()
Tsuga heterophylla
Lännenhemlokki (Tsuga heterophylla) on mäntykasvien (Pinaceae) heimoon kuuluva havupuu. Se kasvaa luonnonvaraisena Pohjois-Amerikan länsirannikolla. Lännenhemlokki on suurimmaksi kasvava laji hemlokkien suvussa ja voi saavuttaa 50–70 metrin pituuden ja 2,7 metrin rungonpaksuuden. Laji on Länsi-Kanadassa tärkeä metsätalouspuu.
Lännenhemlokkia on Suomessa koeviljelty arboretumeissa ja kasvitieteellisissä puutarhoissa. Mustilan arboretumissa Elimäellä on yli 60-vuotias ja 25 metriä korkea lännenhemlokkimetsä.
Pruche de l'Ouest
(
法語
)
由wikipedia FR提供
Tsuga heterophylla
La Pruche de l'Ouest, Tsuga de Californie, Tsuga de l'Ouest ou Hemlock de l'Ouest (Tsuga heterophylla ) est une espèce d'arbre appartenant au genre Tsuga de la famille des Pinaceae[1].
Ce conifère atteint des tailles considérables de 50-70 mètres de haut[1], exceptionnellement 78 mètres, et des diamètres de 2,7 mètres au tronc.
C'est la plus grande de toutes les espèces de pruches suivie par la Pruche subalpine (Tsuga mertensiana) atteignant des hauteurs maximales de 59 mètres.
![src=]()
"Jeune" Tsuga heterophylla croissant en
épiphyte ; accroché sur le tronc vivant d'un vieil arbre dans une forêt ancienne tempérée (Hoh Rainforest)
![src=]()
Tronc-nurserie de
T. heterophylla et sa
pépinière naturelle de jeunes Tsugas issus du semis naturel ;
Ces troncs sont caractéristiques des forêts anciennes ou à haute
naturalité. Champignons et bactéries transforment le
bois-mort qui reste alors humide, même en été grâce à des substances fongiques et bactériennes
mucilagineuses retenant l'eau dans le bois.
Ces troncs nourriciers sont utiles à diverses espèces, dont aux
salamandres sans poumons, vulnérables à la
dessiccation, qui viennent y manger des limaçons, escargots, insectes, etc.
La pruche de l'ouest est l'arbre emblème de l'État de Washington.
Aire de répartition
Sa distribution naturelle s'étend sur la côte Ouest de l'Amérique du Nord.
Sa limite la plus nordique est dans la péninsule Kenai en Alaska et la plus méridionale dans le nord de Sonoma County en Californie[1]. Sa distribution coïncide avec les forêts pluviales tempérées et l'ensemble de son étendue se situe à moins de 100 kilomètres de la côte Ouest.
Ce Tsuga a été introduit en Europe en 1851[1].
On le cultive dans la partie occidentale de l'Europe pour son bois[1], mais en Europe centrale, il succombe aux grands froids et on ne le plante qu'à titre ornemental dans des parcs[1].
Habitat
La Pruche de l'Ouest croît généralement à basse altitude ; jusqu'à 600 mètres au-dessus du niveau de la mer, mais jusqu'à 1 600 mètres dans sa distribution en Ohio. Bien qu'il s'agisse d'une espèce climacique des forêts anciennes et matures, elle présente une certaine versatilité en termes de résilience écologique en particulier pour ses capacités de recolonisation des sites endommagés).
S'accommodant de la pénombre, cette essence apprécie les sols humides.
Généralement, les populations situées à l'intérieur des côtes présentent une meilleure résistance au gel et à la sècheresse que les populations côtières. Il existe une population à l'intérieur des terres qui se situe dans les montagnes Rocheuses du Sud-Ouest de la Colombie-Britannique, dans le Nord de l'Ohio et l'Ouest du Montana.
Description
Ses aiguilles mesurent de 7 à 18 mm[1].
Contrairement à celle du Pruche du Canada, ses aiguilles ne se rétrécissent pas aux extrémités[1].
La face intérieure porte deux bandes de stomates blanches si larges qu'elles se touchent presque[1].
Les cônes femelles de 20 à 25 mm ont des écailles arrondies nettement plus longues que larges[1].
Voir aussi
Pruche de l'Ouest: Brief Summary
(
法語
)
由wikipedia FR提供
Tsuga heterophylla
La Pruche de l'Ouest, Tsuga de Californie, Tsuga de l'Ouest ou Hemlock de l'Ouest (Tsuga heterophylla ) est une espèce d'arbre appartenant au genre Tsuga de la famille des Pinaceae.
Ce conifère atteint des tailles considérables de 50-70 mètres de haut, exceptionnellement 78 mètres, et des diamètres de 2,7 mètres au tronc.
C'est la plus grande de toutes les espèces de pruches suivie par la Pruche subalpine (Tsuga mertensiana) atteignant des hauteurs maximales de 59 mètres.
![src=]()
"Jeune"
Tsuga heterophylla croissant en
épiphyte ; accroché sur le tronc vivant d'un vieil arbre dans une forêt ancienne tempérée (Hoh Rainforest)
![src=]()
Tronc-nurserie de T. heterophylla et sa
pépinière naturelle de jeunes Tsugas issus du semis naturel ;
Ces troncs sont caractéristiques des forêts anciennes ou à haute
naturalité. Champignons et bactéries transforment le
bois-mort qui reste alors humide, même en été grâce à des substances fongiques et bactériennes
mucilagineuses retenant l'eau dans le bois.
Ces troncs nourriciers sont utiles à diverses espèces, dont aux
salamandres sans poumons, vulnérables à la
dessiccation, qui viennent y manger des limaçons, escargots, insectes, etc.
![src=]()
Cônes de Pruche de l'Ouest
Muséum de Toulouse ![src=]()
Tsuga heterophylla -
Muséum de Toulouse La pruche de l'ouest est l'arbre emblème de l'État de Washington.
Marþöll
(
冰島語
)
由wikipedia IS提供
Marþöll (fræðiheiti: Tsuga heterophilla) er barrtré sem vex í vesturhluta Norður-Ameríku, aðallega nálægt sjó. Það verður vanalega 30-60 metra hátt í heimkynnum sínum.[2] Marþöll er mjög skuggþolin og getur vaxið lengi undir trjáskermi. Toppsprotinn slútir eins og á flestum öðrum þöllum. Vaxtasvæðið spannar frá suðaustur-Alaska til Kaliforníu.[3] Fjallaþöll er skyld tegund.
Á Íslandi
Mikið var flutt inn af fræi á sjötta áratug síðustu aldar. Ræktun gafst ekki vel og fá tré lifðu af.[4] Stálpuð tré má m.a. finna á Hallormsstað, Skorradal og í Grasagarði Reykjavíkur. Ræktun krefst skjóls.[5]
Heimildir
Marþöll: Brief Summary
(
冰島語
)
由wikipedia IS提供
Marþöll (fræðiheiti: Tsuga heterophilla) er barrtré sem vex í vesturhluta Norður-Ameríku, aðallega nálægt sjó. Það verður vanalega 30-60 metra hátt í heimkynnum sínum. Marþöll er mjög skuggþolin og getur vaxið lengi undir trjáskermi. Toppsprotinn slútir eins og á flestum öðrum þöllum. Vaxtasvæðið spannar frá suðaustur-Alaska til Kaliforníu. Fjallaþöll er skyld tegund.
Tsuga heterophylla
(
義大利語
)
由wikipedia IT提供
La tsuga occidentale[2] o abete candadese occidentale[3][4] (Tsuga heterophylla (Raf.) Sarg.) è una specie di Tsuga della costa ovest dell'America settentrionale, con il suo limite nord-occidentale sulla Penisola di Kenai (Alaska) e il suo limite sud-orientale nella contea di Sonoma (California).[5][6]
Habitat
La Tsuga heterophylla è una componente integrale delle foreste del Nord-ovest Pacifico a ovest della Catena Costiera, dove è una specie climax. È anche un importante albero da legname in tutta la regione, insieme a molte delle grandi conifere ad essa associate.[7]
Descrizione
La tsuga occidentale è una grande conifera sempreverde che cresce fino a 50-70 m di altezza, eccezionalmente 83,34 m,[8] e con un tronco di diametro fino a 2,7 m. È la più grande specie di abete canadese, con quello immediatamente più grande (abete delle rocce, T. mertensiana) che raggiunge un massimo di 59 m. La corteccia è marrone, sottile e coperta di solchi. La corona ha una forma conica molto netta e ampia negli alberi giovani con un germoglio principale fortemente afflosciato, che diventa cilindrico negli alberi più vecchi; gli alberi vecchi possono non avere rami nei 30-40 m più bassi. In tutte le età, si distingue rapidamente dalle punte dei ramoscelli penduli. I germogli sono marroni color camoscio molto pallido, quasi bianchi, con una pubescenza pallida lunga circa 1 mm. Le foglie sono aghiformi, lunga 5-23 mm e larga 1,5-2 mm, fortemente appiattita nella sezione trasversale, con un margine finemente seghettato e un apice rozzamente acuminato. Sopra sono di colore verde da medio a scuro; la parte inferiore ha due caratteristiche fasce bianche di stomi con solo una stretta nervatura centrale verde tra le fasce. Sono disposte a spirale sui germogli, ma sono attoricigliate alla base giacendo in due file su ciascun lato del germoglio. Gli strobili sono piccoli, penduli, esilmente cilindrici, lunghi 14-30 mm e larghi 7-8 mm quando sono chiusi, aprendosi fino a 18-25 mm. Hanno 15-25 squame sottili e flessibili, lunghe 7-13 mmg. Gli strobili immaturi sono verdi, maturando marroni-grigi 5-7 mesi dopo l'impollinazione. I semi sono marroni, lunghi 2-3 mm, con una esile aletta marrone pallido, lunga 7-9 mm.[5][6]
Ecologia
La tsuga occidentale è strettamente associata alle foreste pluviali temperate, e la maggior parte del suo areale è a meno di 100 km dall'Oceano Pacifico. C'è tuttavia una popolazione nell'entroterra nei Monti Columbia nella Columbia Britannica, nell'Idaho settentrionale e nel Montana occidentale. Essa cresce per la maggior parte a basse quote, dal livello del mare a 600 m, ma fino a 1 800 m nella parte interna del suo areale in Idaho.[5][6]
È un albero che tollera molto bene l'ombra; tra le specie associate nel Nord-ovest Pacifico, è eguagliato o superato nella tolleranza all'ombra solo dal tasso del Pacifico e dall'abete amabile.[7] Le piante giovani crescono tipicamente sotto la volta di altre conifere come il peccio di Sitka o l'abete di Douglas, dove possono persistere per decenni aspettando di sfruttare un varco nella volta. Alla fine sostituiscono queste conifere, che sono relativamente intolleranti all'ombra, nella foresta climax. Tuttavia, le tempeste e gli incendi boschivi creeranno apeerture sempre più grandi nella foresta dove queste altre specie possono poi rigenerarsi.
La crescita iniziale è lenta; le pianticelle di un anno sono alte comunemente solo 3-5 cm, e quelle di due anni 10-20 cm. Una volta stabiliti, gli alberelli in piena luce possono avere un tasso medio di crescita di 50-120 cm (raramente 140 cm) all'anno finché sono alti 20-30 m, e in buone condizioni 30-40 cm all'anno quando sono alti 40-50 m. L'esemplare più alto, alto 82,83 m, è nel Parco statale di Prairie Creek Redwoods, California (Stati Uniti). Ha una vita lunga, con alberi che si sa hanno oltre 1.200 anni.[6]
La tsuga occidentale forma associazioni ectomicorrizali con alcuni ben noti funghi eduli come i cantarelli (Cantharellus formosus, C. subalbidus, e Craterellus tubaeformis).[9][10]
Usi
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Tsuga occidentale giovane
La tsuga occidentale è l'albero ufficiale dello stato di Washington.[11]
Coltivazione
La tsuga occidentale è coltivata come pianta ornamentale nei giardini dei suoi habitat nativi e lungo la Costa Pacifica, dove la sua migliore affidabilità si vede nelle regioni più umide. In aree relativamente asciutte, come presso Victoria (Canada), è esigente per le condizioni del suolo. Ha bisogno di un alto livello di materia organica (il legno ben marcito di un vecchio tronco o ceppo è meglio; i letami animali possono avere troppo azoto e sale), in un suolo umido e acido. Si coltiva anche nelle regioni temperate in tutto il mondo. Ha vinto il Premio al merito del giardinaggio della Royal Horticultural Society.[12]
Silvicoltura
Quando è ben piantata sulle rive di un fiume, la tsuga occidentale può aiutare a ridurre l'erosione.
Fuori del suo areale nativo, la tsuga occidentale è di importanza nella silvicoltura, (come legno dolce) per la produzione di legname e carta, si usa per fare porte, lavori di falegnameria e mobili.[13] Può anche essere una pianta ornamentale in grandi giardini, in Europe nord-occidentale e Nuova Zelanda meridionale.
Si è naturalizzata in alcune parti della Gran Bretagna e della Nuova Zelanda, non così estesamente da essere considerata un albero di una specie aliena, ma di una specie introdotta.
![src=]()
La
T. heterophylla cresce spesso su
legno in decomposizione, come tronchi protettori e ceppi tagliati
Cibo
Il fellogeno edule può essere raccolto raschiando fette di corteccia rimossa. I trucioli che ne risultano si possono mangiare immediatamente, o possono essere essiccati e spremuti in torte per la conservazione. La corteccia serve anche come fonte di tannino per la concia.
Gli aghi (foglie) teneri della nuova crescita si possono masticare direttamente o trasformati in un tè amaro, ricco di vitamina C (simile ad altre specie di tsuga e di pino).
I rami di tsuga occidentale si usano per raccogliere le uova di aringa durante la deposizione in Alaska sud-orientale. I rami forniscono una superficie facilmente raccoglibile perché le uova possano attaccarsi oltre a fornire un gusto caratteristico. Questa pratica trae origine dai metodi tradizionali di raccolta usati dai Nativi alascani dell'Alaska sud-orientale, specificamente dai Tlingit.
Note
-
^ (EN) Tsuga heterophylla, su IUCN Red List of Threatened Species, Versione 2020.2, IUCN, 2020.
-
^ Tsuga occidentale (Tsuga heterophylla), su STIHL - Lessico degli alberi. URL consultato il 10 novembre 2017.
-
^ Tsuga heterophylla, su Natural Reources Conservation Service PLANTS Database, USDA. URL consultato il 12 dicembre 2015.
-
^ BSBI List 2007 (XLS), su bsbi.org.uk, Botanical Society of Britain and Ireland. URL consultato il 17 ottobre 2014 (archiviato dall'url originale il 25 gennaio 2015).
-
^ a b c A. Farjon, Pinaceae. Drawings and Descriptions of the Genera, Koeltz Scientific Books, 1990, ISBN 3-87429-298-3.
-
^ a b c d Gymnosperm Database: Tsuga heterophylla Archiviato il 24 settembre 2005 in Internet Archive.
-
^ a b E.C. Packee, Tsuga heterophylla, in Russel M. Burns e Barbara H. Honkala (a cura di), Conifers, Silvics of North America, vol. 1, Washington, D.C., United States Forest Service (USFS), United States Department of Agriculture (USDA), 1990. Ospitato su Northeastern State and Private Forestry (www.na.fs.fed.us/).
-
^ M. D. Vaden Arborist, Tallest known Hemlock, Tsuga heterophylla, su mdvaden.com.
-
^ Susie M. Dunham, Thomas E. O'Dell e Randy Molina, Forest stand age and the occurrence of chanterelle (Cantharellus) species in Oregon’s central Cascade Mountains (PDF), in Mycological Research, vol. 110, 2006, pp. 1433–40, DOI:10.1016/j.mycres.2006.09.007, PMID 17123812 (archiviato dall'url originale il 14 agosto 2011).
-
^ M.J. Trappe, Habitat and host associations of Craterellus tubaeformis in northwestern Oregon, in Mycologia, vol. 96, n. 3, maggio–giugno 2004, pp. 498–509, DOI:10.2307/3762170, PMID 21148873.
-
^ State Symbols, su Washington State Government (archiviato dall'url originale il 15 novembre 2007).
-
^ RHS Plant Selector – Tsuga heterophylla, su apps.rhs.org.uk. URL consultato il 7 giugno 2013 (archiviato dall'url originale il 3 dicembre 2013).
-
^ Michael Buckley, A basic guide to softwoods and hardwoods (PDF), su worldhardwoods.com, 2005. URL consultato il 1º ottobre 2017 (archiviato dall'url originale il 19 agosto 2019).
Tsuga heterophylla: Brief Summary
(
義大利語
)
由wikipedia IT提供
La tsuga occidentale o abete candadese occidentale (Tsuga heterophylla (Raf.) Sarg.) è una specie di Tsuga della costa ovest dell'America settentrionale, con il suo limite nord-occidentale sulla Penisola di Kenai (Alaska) e il suo limite sud-orientale nella contea di Sonoma (California).
Kaliforninė cūga
(
立陶宛語
)
由wikipedia LT提供
Kaliforninė cūga (lot. Tsuga heterophylla) – pušinių (Pinaceae) šeimos visžalių spygliuočių medžių rūšis. Auga Šiaurės Amerikos vakarinėje pakrantėje: nuo Kenajaus pusiasalio šiaurėje iki Sonomos apygardos (šiaurės Kalifornija) pietuose.
Aukštis 50-70 m, nors gali užaugti ir iki 78 m. Kamieno skersmuo iki 2,7 m. Šiuo metu (pagal M.Vaden, St.Sillett, 2011) auganti aukščiausia kaliforninė cūga yra 82,9 m aukščio. Laja labai tanki, kūgiška, vėliau virsta cilindriška. Senų medžių žemiausios šakos prasideda 30-40 m aukštyje. Žievė ruda, plona, raukšlėta. Spygliai, 5-23 mm ilgio, 1,5–2 mm pločio, tamsiai žali, paplokšti. kankorėžiai nedideli, kybantys, 14-30 mm ilgio ir 7-8 mm pločio. Jauni būna žali, vėliau paruduoja. Sudaryti iš 15–25 plaušelių[1].
Kaliforninė cūga naudojama medienos, popieriaus pramonėje. Tai yra Vašingtono valstijos oficialus simbolinis medis[2].
Šaltiniai
![src=]()
Kaliforninės cūgos kalnuose
Vikiteka
Kaliforninė cūga: Brief Summary
(
立陶宛語
)
由wikipedia LT提供
Kaliforninė cūga (lot. Tsuga heterophylla) – pušinių (Pinaceae) šeimos visžalių spygliuočių medžių rūšis. Auga Šiaurės Amerikos vakarinėje pakrantėje: nuo Kenajaus pusiasalio šiaurėje iki Sonomos apygardos (šiaurės Kalifornija) pietuose.
Aukštis 50-70 m, nors gali užaugti ir iki 78 m. Kamieno skersmuo iki 2,7 m. Šiuo metu (pagal M.Vaden, St.Sillett, 2011) auganti aukščiausia kaliforninė cūga yra 82,9 m aukščio. Laja labai tanki, kūgiška, vėliau virsta cilindriška. Senų medžių žemiausios šakos prasideda 30-40 m aukštyje. Žievė ruda, plona, raukšlėta. Spygliai, 5-23 mm ilgio, 1,5–2 mm pločio, tamsiai žali, paplokšti. kankorėžiai nedideli, kybantys, 14-30 mm ilgio ir 7-8 mm pločio. Jauni būna žali, vėliau paruduoja. Sudaryti iš 15–25 plaušelių.
Kaliforninė cūga naudojama medienos, popieriaus pramonėje. Tai yra Vašingtono valstijos oficialus simbolinis medis.
Westelijke hemlockspar
(
荷蘭、佛萊明語
)
由wikipedia NL提供
De westelijke of westerse hemlockspar (Tsuga heterophylla) is een boom uit de dennenfamilie (Pinaceae). De sierlijke, snelgroeiende conifeer komt voor aan de westkust van Noord-Amerika. De boom bereikt daar een hoogte van 80 m. In Europa kan hij tot 40 m hoog worden. De boom geeft de voorkeur aan kustgebieden met hoge luchtvochtigheid en vocht in de bodem.[1]
Beschrijving
De kroon is piramide- of kegelvormig. De boom heeft een spitse top die enigszins overbuigt. De toppen van de takken hangen iets omlaag. De boomschors is bruin en glad. Oudere bomen zijn donkerder en hebben diepe groeven in de schors.
De twijgen zijn bleek geelbruin en zijn bedekt met lange haren. De knoppen zijn klein, bruin en bolvormig. De westelijke hemlockspar heeft afgeplatte, aromatische naalden met een variabele grootte. De naalden hebben een afgeronde top en zijn glanzend groen aan de bovenzijde. Ze hebben een korte steel en ze laten een rond, oranjekleurig litteken achter als ze afvallen.
De kegels zijn bleekbruin en eivormig, worden 2-3 cm lang en hebben gladde, ronde schubben. De kegels hangen aan het eind van de twijgen omlaag. Onrijpe kegels zijn groen, rijpe zijn bleekgroen.
Toepassingen
De westelijke hemlockspar levert geel hout (met een rozige zweem). Het heet iets beter te zijn dan dat van de oostelijke hemlockspar en wordt gebruikt voor papierpulp, de bouw, kisten et cetera.
Eigenschappen[2]
- Duurzaamheidsklasse : IV kernhout, V spinthout
- Volumieke massa : 450 kg/m²
- Radiale krimp : 1 - 1,1 %
- Tangentiale krimp : 1,6 %
- Werken : 2,6 - 2,7 %
Externe link
Bronnen, noten en/of referenties
Westelijke hemlockspar: Brief Summary
(
荷蘭、佛萊明語
)
由wikipedia NL提供
De westelijke of westerse hemlockspar (Tsuga heterophylla) is een boom uit de dennenfamilie (Pinaceae). De sierlijke, snelgroeiende conifeer komt voor aan de westkust van Noord-Amerika. De boom bereikt daar een hoogte van 80 m. In Europa kan hij tot 40 m hoog worden. De boom geeft de voorkeur aan kustgebieden met hoge luchtvochtigheid en vocht in de bodem.
Vestamerikansk hemlokk
(
挪威語
)
由wikipedia NO提供
Vestamerikansk hemlokk (vitenskapelig navn Tsuga heterophylla) er en art av bartrær innenfor hemlokkslekten i furufamilien (Pinaceae). Den er en av fire arter som vokser i Nord-Amerika. I USA kalles den Western Hemlock.
Beskrivelse
Trærne er middels store til store, gjerne 30-60 meter høye, sjelden inntil 78 meter. Den har konisk trekrone og brun, furete bark. Arten kjennes på at den har en «nikkende» øvre krone eller toppskudd, som henger litt ned. Stammen er oftest ugrenet, og mangler etter hvert grener i den nedre halvdelen etter som treet blir eldre. Unge trær har en bred konisk krone, eldre trær blir mer sylindriske. Diameteren på stammen kan nå 2,5 meter.
Nålene er inntil 2 cm lange, og kjennes spesielt på at undersiden av bladene har spalteåpninger i to smale, hvite bånd på hver side av en tynn, grønn midtribbe. Nålenes overside er mørkegrønne.
Konglene er små (14-30 mm og 7-8 mm brede når de er lukket), smale og med sprikende skjell. Frøene er brune, 2-3 mm lange med en slank 7-9 mm lang brun vinge. Trærne kan bli over 1200 år gamle[2].
![src=]()
Den kraftige parkvarianten
Tsuga heterophylla var. pendula.
Naturlig utbredelse
Arten vokser har sin naturlige utbredelse moh. fra Alaska (Kenai) i nord, via Rocky Mountains sørover til Idaho, Britisk Columbia, Utah, Montana og California. Den er nasjonaltreet i delstaten Washington i USA.
Uplantet utbredelse og bestand
I Norge omfatter utplantinger av vestamerikanske hemlokk i underkant av 2000 dekar, og mesteparten av dette arealet har vært utplantet på 1960-tallet. Den svake kvaliteten på virket og problemer med rotråte er hovedårsakene til at arten ikke har hatt noen sentral posisjon i skogreisningen. Hovedtyngden av utplantingen finnes i Rogaland og Hordaland, med spredte enkeltforekomster langs kysten fra Østlandet (f.eks. Ås) til Lofoten i nord. Treet er ofte brukt i park- og hageanlegg.[3][4]
Fremmed art: Spredning og økologisk effekt
Vestamerikansk hemlokk setter frø tidlig, har hyppige frøsettinger og har rikelig med kongler. Frøene har dessuten vinger noe som gjør at de lett sprer seg med vinden. Arten har dermed gode spredningsegenskaper, og den har også vist god evne til langdistansespredning. Hemlokk er dessuten svært skyggetålende, vokser raskt og den har rundt plantefelt i Norge vist stor evne til foryngelse. I undersøkte eldre plantefelt i Hordaland er opptil 100 000 frøplanter per dekar registrert på tilgrensende kulturflater.[5]
Størrelsen, tettheten og alderen på plantefeltet er i stor grad avgjørende for spredning og effekter. Gode spredningsegenskapene gjør at vestamerikansk hemlokk kan etablere seg langt fra opphavsbestanden dersom de lokale forholdene (vind, jordsmonn etc.) er tilstede. Treet er svært skyggetolerant og kan dermed etablere seg selv i tette skogbestander. Dessuten er treet en klimaksart og det tette barverket stenger etter hvert ute lyset til skogbunnen, noe som vil gi negative effekter på stedegent biologisk mangfold.
Referanser
-
^ Gederaas, L., Moen, T.L., Skjelseth, S. og Larsen, L.K. (red.) (2012). Fremmede arter i Norge – med norsk svarteliste 2012. Trondheim: Artsdatabanken. s. 95. Arkivert fra originalen 18. mai 2015.CS1-vedlikehold: Flere navn: forfatterliste (link)
-
^ The conifer database: http://www.conifers.org/pi/Tsuga_heterophylla.php
-
^ Øyen, B.H., Andersen, H.L., Myking, T.; m.fl. (2009). Økologiske egenskaper for noen utvalgte introduserte bartreslag i Norge. Ås: Norsk institutt for skog og landskap. Arkivert fra originalen 1. oktober 2016.CS1-vedlikehold: Eksplisitt bruk av m.fl. (link)CS1-vedlikehold: Flere navn: forfatterliste (link)
-
^ Øyen, B.H. (2001). «Vestamerikansk hemlokk – gjøkungen blant innførte bartrær i Vest-Norge?» (PDF). Blyttia. Norsk Botanisk Forening. 59 (4): 208–216. ISSN 0006-5269.
-
^ Fremmede arter i Norge: Tsuga heterophylla faktaark http://www2.artsdatabanken.no/faktaark/Faktaark230.pdf
Eksterne lenker
Fremmede arter i Norge: Tsuga heterophylla økologisk risikovurdering
Fremmede arter i Norge: Tsuga heterophylla faktaark
Vestamerikansk hemlokk: Brief Summary
(
挪威語
)
由wikipedia NO提供
Vestamerikansk hemlokk (vitenskapelig navn Tsuga heterophylla) er en art av bartrær innenfor hemlokkslekten i furufamilien (Pinaceae). Den er en av fire arter som vokser i Nord-Amerika. I USA kalles den Western Hemlock.
Tsuga heterophylla
(
Pms
)
由wikipedia PMS提供
Costo artìcol a l'é mach në sbòss. Da finì.
Distribussion
Da finì.
Notissie
Da finì.
Arferiment bibliogràfich për chi a veul fé dj'arserche pì ancreuse
-
Tsuga heterophylla (Raf.) Sarg.
Tsuga heterophylla: Brief Summary
(
Pms
)
由wikipedia PMS提供
Costo artìcol a l'é mach në sbòss. Da finì.
Distribussion
Da finì.
Notissie
Da finì.
Choina zachodnia
(
波蘭語
)
由wikipedia POL提供
Multimedia w Wikimedia Commons Choina zachodnia (Tsuga heterophylla) – gatunek drzewa z rodziny sosnowatych (Pinaceae), pochodzący z Ameryki Północnej.
Morfologia
- Pokrój
- Drzewo osiąga zwykle do 20-40 m wysokości, a najwyższe osobniki do 83 metrów[3].Posiada stożkowatą koronę, przewieszony wierzchołek i zwisające gałęzie. Choinę zachodnią można łatwo rozpoznać po zwisających, długich, młodych pędach i końcach gałązek.
- Liście
- Igły o mieszanej długości od 5 mm do 23 mm (heterophylla znaczy różnolistna), obsadzone spiralnie i wykręcone u podstawy tak, że rozkładają się na obie strony gałązki. Igły na brzegach drobno piłkowane, z wierzchu zielone, pod spodem z dwoma srebrzystoszarymi paskami - zimą mogą zabarwić się na brązowo.
Biologia i ekologia
Igły po roztarciu w palcach przypominają zapachem rośliny baldaszkowate.
Występuje w rejonach o łagodnym, wilgotnym klimacie, w parkach i ogrodach.
Przypisy
Bibliografia
Choina zachodnia: Brief Summary
(
波蘭語
)
由wikipedia POL提供
Choina zachodnia (Tsuga heterophylla) – gatunek drzewa z rodziny sosnowatych (Pinaceae), pochodzący z Ameryki Północnej.
Tsuga heterophylla
(
葡萄牙語
)
由wikipedia PT提供
Tsuga heterophylla: Brief Summary
(
葡萄牙語
)
由wikipedia PT提供
![src=]()
Tsuga heterophylla -
MHNT ![src=]()
Tsuga heterophylla -
MHNT Tsuga heterophylla é uma espécie de conífera nativa da costa oeste da América do Norte, com seu limite de distribuição à noroeste na península de Kenai, no Alasca, e seu limite sudeste, no condado de Sonoma, Califórnia. A árvore é conhecida nos países de língua inglesa como Western Hemlock.
Jedľovec rôznolistý
(
斯洛伐克語
)
由wikipedia SK提供
Jedľovec rôznolistý (Tsuga heterophylla) je mohutný vždyzelený ihličnan z čeľade borovicovité, ktorý dorastá do výšky 50 až 70 metrov, výnimočne aj 78 metrov, s priemerom kmeňa vyše 2,7 metra. Je to najväčší druh z rodu jedľovcov, pričom druhý najväčší jedľovec Mertensov dosahuje výšku maximálne 59 metrov.
Jeho prirodzeným prostredím je západné pobrežie Severnej Ameriky, pričom na severozápade siaha až po polostrov Kenai na Aljaške a na juhovýchode po okres Sonoma County v Kalifornii. Vyskytuje sa v dažďových pralesoch mierneho pásma, no nikde nezasahuje viac ako 100 kilometrov do vnútrozemia. Výnimku predstavuje populácia jedľovca rôznolistého v Skalnatých vrchoch na juhovýchode Britskej Kolumbie, v severnom Idahu a západnej Montane. Väčšinou rastie v nížinách do nadmorskej výšky 600 metrov, no v Idahu sa miestami vyskytuje aj v nadmorskej výške 1 800 metrov.
Iné projekty
Jedľovec rôznolistý: Brief Summary
(
斯洛伐克語
)
由wikipedia SK提供
![src=]()
Jedľovec rôznolistý
![src=]()
Tsuga heterophylla
![src=]()
Tsuga heterophylla
Jedľovec rôznolistý (Tsuga heterophylla) je mohutný vždyzelený ihličnan z čeľade borovicovité, ktorý dorastá do výšky 50 až 70 metrov, výnimočne aj 78 metrov, s priemerom kmeňa vyše 2,7 metra. Je to najväčší druh z rodu jedľovcov, pričom druhý najväčší jedľovec Mertensov dosahuje výšku maximálne 59 metrov.
Jeho prirodzeným prostredím je západné pobrežie Severnej Ameriky, pričom na severozápade siaha až po polostrov Kenai na Aljaške a na juhovýchode po okres Sonoma County v Kalifornii. Vyskytuje sa v dažďových pralesoch mierneho pásma, no nikde nezasahuje viac ako 100 kilometrov do vnútrozemia. Výnimku predstavuje populácia jedľovca rôznolistého v Skalnatých vrchoch na juhovýchode Britskej Kolumbie, v severnom Idahu a západnej Montane. Väčšinou rastie v nížinách do nadmorskej výšky 600 metrov, no v Idahu sa miestami vyskytuje aj v nadmorskej výške 1 800 metrov.
Tsuga heterophylla
(
烏克蘭語
)
由wikipedia UK提供
Поширення, екологія
Країни проживання: Канада (Альберта, Британська Колумбія); США (Аляска, Каліфорнія, Айдахо, Монтана, Орегон, Вашингтон). Росте від рівня моря до 600 м над рівнем моря вздовж узбережжя Тихого океану, в Скелястих горах досягає 1800 м. Росте на різних ґрунтах з рН 3,5-5. Клімат прохолодний морський вздовж узбережжя, холодний гірський на континенті, річна кількість опадів коливається від (500 -) 900-3,800 мм, зменшуючись всередину континента. Сухе літо обмежує поширення в Скелястих горах. Вид дуже симпатричний з Picea sitchensis в більшій частині ареалу. Вкрай тіньовитривалий вид, але має більш коротку тривалість життя, ніж Pseudotsuga menziesii або Picea sitchensis. Уздовж узбережжя може утворювати іноді чисті насадження, але частіше є важливою складовою морського мезотермального хвойного лісу. На Олімпійському півострові Вашингтона дерево досягає максимального розміру, разом з іншими гігантськими хвойними. Його терпимість до тіні дозволяє рости під пологом інших дерев, але товстий моховий шар зазвичай запобігає легкому насінню досягати ґрунту. Замість цього, насіння проростає масово на повалених деревах, звідки кілька з них мають можливість відправляти коріння в ґрунт; в результаті Т. heterophylla часто утворює ряди на місці пріючого дерева.
Морфологія
Дерева до 60 (75) м; стовбур до 200 см діаметра на рівні грудей; крона вузько конічна. Кора сіро-коричнева, луската і помірно тріщинувата. Бруньки яйцеподібні, сіро-коричневі, 2,5-3,5 мм. Листки розміром (5) 10-20 (30) мм, сплющені; нижня поверхня сиза з 2 широкими смугами, верх блискучий зелений (жовто-зелений). Шишки яйцеподібні, розміром (1) 1,5-2,5 (3) × 1-2,5 см. Насіння коричневе, 2-3 мм завдовжки, з тонкими 7-9 мм довжини світло-коричневими крилами. 2n = 24
Використання
Є важливим деревом деревини в Тихоокеанському Північному Заході США і зх. Канаді. На відміну від своїх східних побратимів вид є швидкорослою рослина випереджаючи навіть Дугласій. Деревина використовується для паль, стовпів і залізничних шпал і особливо для будівництва. Велика частина щорічного врожаю йде на деревну масу промисловості для різних застосувань. Цей вид був введений у Великій Британії та інших частинах північного заході Європи в лісові плантації; в більш вологих районах поблизу Атлантичного узбережжя він буде відновлюватися мимовільно. Як надзвичайно тіньовитривале хвойне дерево підходить для зростання широколистяних лісах; проте, так як воно, в свою чергу затіняє все під ним, це не повинно бути зроблено в (напів) природних лісах, де цінується корінна флори. Хоча часто висаджують як зразок дерев у дендраріях і парках, цей вид не дуже використовується в садівництві.
Загрози та охорона
Цей вид не під загрозою і, ймовірно, його чисельність зростає. Цей вид присутній в кількох охоронних територіях, серед яких відомі національні парки.
Посилання
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Tsuga heterophylla
(
越南語
)
由wikipedia VI提供
Tsuga heterophylla là một loài thực vật hạt trần trong họ Thông. Loài này được (Raf.) Sarg. miêu tả khoa học đầu tiên năm 1898.[1]
Chú thích
Liên kết ngoài
Tsuga heterophylla: Brief Summary
(
越南語
)
由wikipedia VI提供
Tsuga heterophylla là một loài thực vật hạt trần trong họ Thông. Loài này được (Raf.) Sarg. miêu tả khoa học đầu tiên năm 1898.
Тсуга западная
(
俄語
)
由wikipedia русскую Википедию提供
Тсуга западная: Brief Summary
(
俄語
)
由wikipedia русскую Википедию提供
アメリカツガ
(
日語
)
由wikipedia 日本語提供
アメリカツガ: Brief Summary
(
日語
)
由wikipedia 日本語提供
![src=]()
Tsuga heterophylla
![src=]()
Tsuga heterophylla
アメリカツガ（米栂、学名：Tsuga heterophylla）は、マツ科ツガ属の常緑針葉樹。
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Tento článok týkajúci sa botaniky je zatiaľ „výhonok“. Pomôž Wikipédii tým, že ho doplníš a rozšíriš. 
Це незавершена стаття про родину Соснові.
Это заготовка статьи по ботанике. Вы можете помочь проекту, дополнив её. 
分類（新エングラー体系） 界 : 植物界 Plantae 門 : 裸子植物門 Gymnospermae 綱 : マツ綱 Coniferopsida 目 : マツ目 Coniferae 科 : マツ科 Pinaceae 属 : ツガ属 Tsuga 種 : アメリカツガ T. heterophylla 学名 Tsuga heterophylla (Raf.) Sarg.[1][2] 和名 アメリカツガ[2] 英名 Western Hemlock[1] 
この項目は、植物に関連した書きかけの項目です。この項目を加筆・訂正などしてくださる協力者を求めています（プロジェクト:植物／Portal:植物）。 
