Western larch is a fast growing, long-lived, deciduous conifer native to alpine and subalpine forests of the northwestern United States and adjacent Canada [4,45,115,154]. Trees over 900 years old have been reported [80,115,116].
One of the world's largest larches, western larch typically grows 100 to 180 feet tall (30-55 m) but can be over 200 feet (60 m) tall [50,57,71,72,115,157], with diameters up to 6 feet (2 m) [50,62,72,157]. Basal area increases rapidly to about age 40, then decelerates and nearly levels off after age 100 [115]. A deep, spreading root system stabilizes these large trees [57,72]. In a synthesis of literature on northwestern trees, Minore [93] ranked western larch root depth in the middle category of 5 categories.
Bark in mature trees is thick and furrowed into large, flaky plates [50,71,115,157]. At age 50, basal bark thickness ranges from 5 to 10 inches (12-25 cm), and at age 100 bark is 10 to 18 inches (25-45 cm) thick [12]. Western larch trunks are usually bare for a half to a third of the height when in stands, while trees in the open may have branches to within a few feet of the ground [71,72,157]. Crowns are generally short, open, and pyramidal with nearly horizontal branches, though branches may droop in the lower crown of older trees grown in the open [50,57,71,72]. Crown length, width, and density were all ranked low in Minore's [93] synthesis of literature on northwestern trees.
Branches are stout and brittle, changing from pubescent to glabrous with age. Buds are small, rounded, and hairless [71,72,157]. As trees mature, clustered epicormic branches replace older branches, beginning with the lower portion of the crown. Eventually, epicormics, which grow from dormant buds at the base of first order branches, comprise the entire crown [83].
Clusters of 15 to 30 slender, soft, spirally-arranged needles 1 to 2 inches (2.5-5.0 cm) long arise from dwarf twigs [71,72,157]. Western larch foliage is replaced annually [55,57].
Male western larch cones are 0.4 inch (1 cm) long [71,157]. Ovulate cones are papery, 1 to 1.5 inches long (2.5-3.5 cm) and 0.5 to 0.6 inch (1.3-1.6 cm) wide with long subtending bracts [12,50,71,72,157]. Seeds are 0.1 inch (3 mm) long with 0.2 inch (6 mm) wings [50,71,72,157].
The preceding description provides characteristics of western larch relevant to fire ecology and is not meant to be used for identification. Keys for identifying western larch are available [40,70,82].
Western larch is considered the most fire-resistant tree in its range [10,17,24,51,89,137]. Fire is an important part of western larch's ecology; without fire or other stand replacing disturbance, western larch will not regenerate successfully and will eventually be replaced by more shade-tolerant species [116].
Fire adaptations: Western larch has many adaptations that enhance its ability to either survive fire or to quickly colonize recently burned areas. While seedlings, saplings, and poles are somewhat susceptible to fire, trees that are 150 to 200 years old or older are able to survive all but the most severe fires [24,116]. It is common for a handful of mature western larch trees to be the sole survivors after fire [24]
Surviving fire: Western larch's extremely thick basal bark protects its cambium from overheating [10,24,48,49,92,116,126,143,155]. Low resin content and light lichen growth also decrease flammability [10,116,143]. Western larch's characteristic high, open crown; open stand habit; and self-pruning lower branches minimize ladder fuels and risk of crown fire [10,24,48,49,59,116,143]. Its deep roots are protected from surface and ground fires [24,49,59,143]. In a synthesis of the literature on northwestern tree species, Minore [93] ranked western larch's bark in the most fire resistant category and its foliage in the least resistant category. He ranked western larch the most fire resistant tree in British Columbia, Washington, Oregon, and Idaho.
Needles of western larch are less flammable than other species' due to their small size. Because they are never more than 5 months old, they maintain a higher water content than other conifers' needles that are replaced every 2 or 3 years [10,24,49,116,143]. Since western larch replaces its needles annually anyway, it is better adapted to defoliation than other conifers. In fact, after defoliation early in the season western larch trees often will produce a 2nd set of needles from heat-resistant woody buds and epicormic branches [10,17,36,48,89]. The small needles also minimize accumulation of surface litter at tree bases [24].
Postburn colonization: Western larch survivors quickly reseed burned-over areas; on mineral soil seedlings develop rapidly and outgrow competitors [10,48,58,85,116,126]. Fire-killed trees may contribute to seeding if fresh cones in the burned crown mature and disperse seed [10]. Seeds are very light and long-winged, allowing trees in nearby stands to reseed even if no onsite seed source is present [10,48]. Since western larch is a very long-lived and fire-resistant species, a potential seed source remains in the area for centuries once it has established [13].
FIRE REGIMES: Wildfires have occurred in western larch forests for over 10,000 years [10,30]. Barrett and others [20] suggest 2 FIRE REGIMES for western larch forests: 1) 25-75 year intervals between mixed-severity fires, and 2) 120-350 year intervals between primarily stand-replacing fires. While the species is primarily associated with these regimes, frequent surface FIRE REGIMES can also support western larch populations [8]. Frequency and severity of fires vary with elevation, aspect, and habitat type.
Frequent understory fires: Warm, dry sites at the lower elevations of western larch's range in western Montana have been characterized by frequent, low-intensity surface fires occurring at 10 to 30 year intervals. These habitat types include Douglas-fir and grand fir. Stand replacing fires occurred in some of these stands at 150- to 400-year intervals [7,10,60].
In ponderosa pine-western larch habitat in Pattee Canyon near Missoula, Montana, fire scars indicate a mean fire return interval of 7.1 years from 1557 to 1918. Fire occurred an average of every 5 to 10 years from 1750 to 1850, and in 10 to 20 year intervals from 1850 through 1900. After 1900, intensity and frequency of fires were reduced until the late 1900s, when high intensity fires swept through north and south slopes of the canyon [60].
In the Flathead National Forest of western Montana, underburning occurred on average every 20 to 30 years in even-aged ponderosa pine-western larch stands before 1900, with stand replacing fires occurring at 150- to 400-year intervals. From 1735 to 1900 in the grand fir habitat type of western Montana, an average fire return interval of 17 years (range 3-32) maintained western larch as the most abundant tree followed by lodgepole pine and Douglas-fir. Western larch was also found on 3 Douglas-fir habitat type sites with average intervals of 7 (range 2-28), 16 (range 4-29), and 19 (range 2-48) years [15].
Arno's [8] literature review reported that understory FIRE REGIMES prior to 1900 in ponderosa pine-mixed conifer habitat types of western North America favored western larch and other fire resistant species such as ponderosa pine and Jeffrey pine. From 1600 to 1900 in several relict habitat types where western larch occurs in western Montana, fire return intervals averaged 27 (range 17-35) years in the Douglas-fir-big huckleberry (V. membranaceum) type, 25-30 years in the Douglas-fir-dwarf huckleberry (Gaylussacia dumosa) type, and 24 (range 9-42) years in the subalpine fir-queen cup beadlily (Clintonia uniflora) type [7].
Mixed-severity fires: Much of the northern Rocky Mountains are characterized by 30- to 100-year-interval fires of varying severity, which favor open stands of western larch and Douglas-fir in Douglas-fir, western larch, and lodgepole pine habitat types [8,14]. In the Bob Marshall Wilderness, Montana, western larch-Douglas-fir-lodgepole pine and ponderosa pine forest types were historically maintained by mixed severity fire regimes. Many live western larches in this area had 1 to 3 fire scars, and 1 was found with 4 scars. Fire return intervals in this area are nearly twice as long as historic mean intervals [14].
In western larch-Douglas-fir forests of the North Fork of Glacier National Park, Montana, mean fire frequency from 1650 through 1935 was 36 years in relatively dry sites and 46 years in relatively moist sites. In the drier areas, up to 7 understory fires occurred between stand-replacing fires, which occurred at a mean interval of 141 years. Only 1 or 2 understory fires occurred between the less frequent stand-replacing fires (186-year mean intervals) on moister sites [20].
On dry subalpine fir and cool, moist Douglas-fir habitat types that were codominated by western larch, lodgepole pine, and Douglas-fir, average fire return intervals ranged between 30 and 75 years. Severity varied from understory burns to stand-replacing fires [10].
Infrequent stand-replacement fires: In western larch-Douglas-fir forests of northwestern Montana, average fire return intervals from 1735 to 1976 were 120 years in valleys and montane slopes and 150 years for subalpine slopes. Most fires were small and of moderate intensity with occasional patches of high intensity. Though some stands had as many as 6 fires during the period studied, most stands had only 1. A trend of decreasing mean frequency with increasing elevation was noted, and fires on north aspects were more intense and less frequent. Multiple burns occurred primarily on south-facing slopes. In these forests, single burns of low to moderate intensity thinned the overstory and tended to favor regeneration of mixed conifers with patches of seral species, while single intense burns resulted in even-aged forests. Intense, repeated burns (fire return interval <50 years) created shrubfields or homogeneous stands, usually of lodgepole pine [35].
From 1650 to 1935, relatively moist western larch-Douglas-fir forests in Glacier National Park had stand replacement fires at mean intervals of 140 to 340 years [20]. In subalpine fir and Engelmann spruce habitat types in the Middle Fork Drainage of Glacier National Park, Montana, lodgepole pine and western larch stand-replacement intervals were generally 150 to 300 years but as short as 25 years [19], and in grand fir habitat in the Swan Valley of Montana, stand-replacing fires occurred in average 150-year intervals, ranging from less than 20 to more than 300 years [2].
Moist sites of grand fir, subalpine fir, western redcedar, and western hemlock habitat types, which were dominated by western larch, lodgepole pine, Douglas-fir, and Engelmann spruce, burned primarily as stand-replacement fires with average fire return intervals of 120 to 350 years [10].
In western redcedar-hemlock (Tsuga) forests of northern Idaho, fire free intervals ranged from 50 to 100 years with varied intensity. In subalpine fir habitat type, low to medium intensity fires occurred at intervals greater than 150 years [9].
FIRE REGIMES for plant communities and ecosystems where western larch is a common associate are summarized below. Find further 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".
Community or Ecosystem Dominant Species Fire Return Interval Range (years) grand fir Abies grandis 35-200 [8] Rocky Mountain juniper Juniperus scopulorum 103] western larch* Larix occidentalis 25-350 [2,4,6,7,8,9,10,14,15,19,20,35,60] Engelmann spruce-subalpine fir Picea engelmannii-Abies lasiocarpa 35 to > 200 [8] Rocky Mountain lodgepole pine* Pinus contorta var. latifolia 25-300+ [8,113] interior ponderosa pine* Pinus ponderosa var. scopulorum 2-30 [8,18,87] Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 [8,11,15] Oregon white oak Quercus garryana < 35 western redcedar-western hemlock Thuja plicata-Tsuga heterophylla > 200 mountain hemlock* Tsuga mertensiana 35 to > 200 [8] *fire return interval varies widely; trends in variation are noted in the species summaryFire is an important management practice for maintaining western larch [10,30,60,91]. Ideally, prescribed burns should expose well-distributed patches of mineral soil and reduce sprouting potential of competitors [67,114,123]. However, even areas with very little burned surface result in significantly better western larch regeneration than unburned sites [10,130]. In good seed crop years, overstocking may result in mesic habitats where too much mineral soil is exposed, and thinning may be necessary to facilitate a vigorous stand [37,67,114,123]. Harsh sites with poor regeneration potential may require planting after burning [10,37].
Norum [67,97] provides detailed recommendations for prescribed burning in western larch-Douglas-fir forests. Based on studies of fire and harvest regimes, Antos and Shearer [2] make recommendations for management practices on grand fir-queencup beadlily habitat type in northwestern Montana.
Timing and Site Conditions: The timing of prescribed burns is important for western larch site preparation; large fuels should be dry and soil moisture low in order to expose mineral soil [10,37,97,99,123]. Norum [98] reported that 10 to 17% water content in small diameter (<4 inch (<10 cm)) fuels is a safe and effective range for burning in western larch-Douglas-fir habitat. Spring and early summer fires usually burn only the surface of the duff layer, while late summer or early fall fires after dry summers tend to be more effective at exposing enough mineral soil for larch regeneration. August or early September, before the fall rains, are the best times for burning north-facing slopes, but on other aspects, there is more flexibility for timing a successful burn [10,37,97,99,123]. Timing of seed dispersal should also be considered when planning fall fires; burning before seedfall is preferable [37]. Depending on site conditions, removing duff from bases of western larch trees to prevent cambium and root damage and/or thinning understory to reduce ladder fuels may be necessary prior to burning [16,67,123].
Fire Intensity: An adequate seedbed for western larch usually results from moderate intensity fires in dry duff. High intensity fires may expose too much mineral soil and result in overstocking [10,37]. Prescribed burning after clearcutting or shelterwood cutting is sometimes used to mimic the effects of severe wildfires on western larch habitat [10,148].
While western larch seedlings usually establish best on severely burned sites [109], underburning may lead to consistent successful natural regeneration but requires careful attention to fuel and site conditions [10,96,104,114]. Harvey and others [69] found burning to remove slash reduced ectomycorrhizal activity after partial cuts in western larch-Douglas-fir forests of northwestern Montana. They recommend against burning to remove slash on harsh sites where understory competition may limit conifer germination or where soil organic matter is low. They suggest underburning is better suited for areas where excessive regeneration is expected or where understory vegetation is desired, especially if burn conditions are chosen to limit duff reduction, which in turn will limit conifer (including western larch) germination.
Models: Reinhardt and Ryan [109,110] present a model for predicting postfire mortality of western larch and 6 other western conifers using bark thickness and percent crown volume. Desired levels of mortality can be predicted using tree species, diameter, height and crown ratio, and maximum allowable flame length. FIRE-BCG simulates fire succession on coniferous forest landscapes of the northern Rocky Mountains, including western larch habitat [78], and FIRESUM models tree establishment, growth, mortality, fuel accumulation, fire behavior, and fuel reduction in ponderosa pine/Douglas-fir forests of the inland northwest [77].
Western larch occurs in mountain valleys and lower slopes, often in somewhat swampy areas [50,71]. It needs well-lighted areas for maximum development, so it performs best in open stands [72]. Western larch is usually found at elevations of 1,500 to 5,500 feet (460-1,700 m) in the northern portions of its range and may be found at elevations over 7,000 feet (2,100 m) in the southern parts of its distribution [50,72,117]. Latitude and elevation affected genetic variation patterns of western larch populations in the Rocky Mountains. Populations from more northern areas and from high elevations had lower growth potential, lower resistance to disease, and lower survival [108]. Elevational ranges for some states and 1 province in western larch's range are:
Montana 3,000-7,200 feet (900-2200 m) [12,79] Oregon 3,500-6,500 feet (1000-2000 m) Washington 2,000-5,500 feet (600-1700 m) [79] British Columbia 2,000-5,550 feet (600-1700 m) [12]Climate: Western larch occupies relatively cool, moist climatic zones. Its upper elevational range is limited by low temperatures, while the lower extreme is limited by low precipitation [45,46,115,117].
Average climatic conditions for western larch's range are [115]:
Temperature 45ð Fahrenheit (7ð C) Maximum temperature 84ð Fahrenheit (29ð C) Minimum temperature 15ð Fahrenheit (-9ð C) Growing season temperature 60ð Fahrenheit (16ð C) Frost free days 60-160 days Annual precipitation 28 inches (710 mm) Growing season precipitation 6 inches (160 mm) Snowfall 103 inches (2620 mm)Climatic conditions for 4 forest habitat types where western larch occurs are [45]:
Douglas-fir grand fir western redcedar-Soil: Western larch is found on a wide variety of soil types, most of which are derived from bedrock or glacial till, but some are of loessial or volcanic ash origin. Deep, porous soils, such as those of mountain slopes and valleys are ideal, and growth is related to soil depth [46,72,115,116,117]. Western larch is also quite dependent on mineral soil or burned seedbeds, more so than any associated tree species including lodgepole pine [46,115]. Western larch is adapted to medium and coarse textured soils with a pH of 6 to 7, and has no salinity tolerance [154].
Topography: Western larch occupies valley bottoms, benches, and mountain slopes. It is found on all exposures but is more common on north and east aspects. South and west exposures are often too severe for seedling establishment [115,116]. This trend is more pronounced in the southern parts of its range, where it is found almost exclusively on north- and east-facing slopes [45,46].
Harsh environments: Western larch has moderate to high resistance to wind throw because its root system provides good anchorage. It is adapted to a wide range of temperatures, but since buds open earlier than associated conifers, hard frosts in late spring may result in cone crop loss [117]. Frozen seed cones are associated with nighttime air temperatures of 25ð Fahrenheit (-4ð C) or less [27,130]. Snow and ice are generally not threats to western larch survival. Wet snow when needles are present (early spring or late fall) may cause snow bend, but rarely results in permanent damage [117].
Mature western larch trees are more fire-resistant than any other species in their range. (Refer to Fire Ecology or Adaptations for more information.) Unless a smoldering surface fire or ground fire girdles boles or the buds are killed by torching, mature western larch trees will survive all but the most severe fires [10,48,61]. Peterson and Ryan [105] found that death of dormant buds on burned western larch occurred 20% lower on trees than foliage death.
Seedlings and saplings of western larch are readily killed by fire [61]. They are less tolerant than those of ponderosa pine [17,89], but may tolerate low-severity underburning better than white fir (A. concolor), lodgepole pine, or Douglas-fir [155].
Larch forests provide food and cover for a wide range of fauna. Rodents eat seeds and seedlings, birds forage for insects and nest in western larch, and squirrels often cut and cache cones. Deer, elk, and moose browse larch, though probably only as a last resort, and black bears forage on sugars that are concentrated in the sap layer in the spring [117,131].
Several studies have investigated the importance of western larch forests to woodpeckers. McClelland [90] found that pileated woodpeckers, a sensitive species dependent on old-growth western larch forests, used 17 times more western larch trees than Douglas-fir even though Douglas-fir trees were 5 times more abundant. Hadfield and Magelsson [62] reported all western larch trees in their 5-year postburn study showed signs of woodpecker foraging, and most feeding occurred in 1st year after tree death. After stand replacing fires in conifer forests of the northern Rocky Mountains, Hutto [74] found evidence of woodpecker foraging on 64% of western larch trees larger than 3.9 inches (10 cm) d.b.h. compared with 81% of ponderosa pine, 48% of Douglas-fir, 2.3% of Engelmann spruce, and 0.2% of lodgepole pine.
Palatability/nutritional value: Western larch appears to be unpalatable to most big game animals, but it is eaten as emergency food [115,117]. Its seeds are palatable to small birds and mammals, although larger seeds are preferred [131]. Larch needles provide a major source of food to several species of grouse [12].
Nutrient values for western larch needles, twigs, and other tree parts have been reported from 2 sites in western Montana [140]. Whole tree values have also been published [139]. Western larch needles at two locations in eastern Washington contained 2.0% and 1.7% nitrogen, respectively [57]. Green needles from Lubrecht Experimental Forest in western Montana, had a mean ash content of 5.8% with a range of 3.47 to 8.16%, and those from Coram Experimental Forest, Montana, had mean ash content of 5.3% with a range of 4.9 to 8.9%. The following table summarizes nutrient values for needles from these 2 sites [140].
Lubrecht mean Lubrecht range Coram mean Coram range Calcium (õg/g) 3,031 2,000-4,800 2,213 1,980-2,390 Copper (õg/g) 8.3 5.0-15.2 15.5 10.7-35.2 Iron (õg/g) 86.8 41-173 126 109-218 Potassium (õg/g) 6,405 2,800-9,760 4,958 4,390-5,388 Magnesium (õg/g) 1,098 692-1,592 1,083 1,005-1,113 Manganese (õg/g) 216 81-405 181 160-239 Nitrogen (õg/g) 13,518 9,730-15,540 23,320 17,920-28,923 Sodium (õg/g) 61.4 24.4-123.0 56 45-125 Phosphorus (õg/g) 2,343 1,678-3,189 2,960 1,894-3,269 Zinc (õg/g) 15.8 6.0-35.6 24.6 21.1-27.7Cover value: Woodpeckers and other cavity nesters utilize western larch. Around its decaying interior, a dead western larch tree retains a protective layer of sapwood, which provides nesting, roosting, and feeding opportunities. Flying squirrels, woodpeckers, owls, and various songbirds nest in rotting western larch cavities. Snags are used by osprey, bald eagles, and Canada geese for nesting [12], and raptors may nest in brooms of trees infected with dwarf mistletoe [25].
Except when it is young, western larch is rarely found in pure stands. Its most
common tree associate is Douglas-fir (Pseudotsuga menziesii), and on
low-elevation dry sites it is found with ponderosa pine (Pinus ponderosa).
Common associates in warm, moist forests include grand fir (Abies
grandis), western hemlock (Tsuga heterophylla), western redcedar
(Thuja plicata), and western white pine (P. monticola). In cool,
moist, subalpine forest types Engelmann spruce (Picea engelmannii),
subalpine fir (A. lasiocarpa), lodgepole pine (Pinus contorta), and mountain
hemlock (Tsuga mertensiana) are more common.
Hardwoods that occur with western larch include paper birch (Betula papyrifera),
black cottonwood (Populus balsamifera ssp. trichocarpa), and quaking aspen
(P. tremuloides) [72,115,116,126,132].
Major understory associates include common beargrass (Xerophyllum tenax), huckleberry
(Vaccinium spp.), thimbleberry (Rubus parviflorus), menziesia (Menziesia ferruginea),
ninebark (Physocarpus malvaceus), serviceberry (Amelanchier spp.),
Oregon boxwood (Paxistima myrsinites), and bearberry (Arctostaphylos uva-ursi).
Western larch is not considered a climax species, but it is a
long-lived early successional species. Refer to Successional Status
for more details [34,53,88,116,156]. Classifications describing
plant communities in which western larch is an important seral species include the following:
Idaho: [33,34,64,144]
Montana: [65,66,106]
Oregon: [51,63]
Washington: [34,51,63]
Wood Products: Western larch is one of the most important timber-producing species in the western United States and western Canada. It has the densest wood of the northwestern conifers and is also very durable and moderately decay-resistant. Its high heating value makes it one of the best fuel woods in the region. The wood is also used commercially for construction framing, railroad ties, pilings, mine timbers, interior and exterior finishing, and pulp, and burned snags are often used to make shakes [12,50,72,115,154]. High sugar content of western larch makes it undesirable for concrete forms because the sugars react chemically with the concrete [117]. Faurot [43] describes methods for estimating total volumes of western larch wood, wood residue, and bark.
Non-wood uses: Native Americans used western larch for treatment of cuts and bruises, tuberculosis, colds and coughs, sore throats, arthritis, skin sores, cancer, and for blood purification [68,153]. They also made syrup from the sap, ate the cambium, and chewed solidified pitch as gum [68]. Arabinogalactan, the gum from the tree, is used for lithography and in food, pharmaceutical, paint, ink and other industries. The most desirable sources of this gum are waste butt logs. Oleoresin from western larch is used to produce turpentine and other products [117].
Western larch's active growth occurs from May through August [115,154]. Vegetative development of western larch proceeds as follows:
Stage of Development Timing Buds begin to appear early fall [115] Buds swell, then open late March and April [121] Needle growth declines mid-May Diameter growth begins mid-May Diameter growth peaks, needle growth ends, height growth begins mid- to late June Height growth peaks mid-July Height growth complete mid-August [132]Reproductive development in western larch proceeds as follows:
Stage of Development Timing Notes Cone initiation early summer [101,115] ---- Buds appear early fall [115] ---- Pollen and seed cone buds develop prior to winter dormancy [101,115] ---- Pollen and seed cone development begins late March and April [121] ---- Pollen and seed conelets appear mid-April to mid-May ---- Pollination late April to early June [115] ---- Fertilization June to July [102,115] Fertilization occurs 6-8 weeks after pollination. Cones mature mid- to late August Cones mature faster during warmer summers. Cone opening begins late August and early September [115,117] Long periods of cool or moist weather may delay opening [115]. 80% of seeds dispersed mid-October [115,117,121,125] Seeds dispersed later usually have lower viability [125]. Cones fall winter Some cones may remain on trees through the next summer [115]. Germination late April through early June [115] Germination roughly coincides with snowmelt and occurs 1-2 weeks before that of associates. Germination occurs earlier on lower elevation or exposed sites and later at upper elevations or in sheltered areas [117].Survivors: Young larch that are wounded by surface fires often heal and survive for centuries [10]. Trees defoliated by May slash burning may produce new needles 1 month later, and appear completely recovered within 2 years [49]. One year after underburning shelterwood units in Idaho, western larch overstory mortality was 7% [136]. After prescribed underburning of Douglas-fir-western larch forest in western Montana, western larch's radial growth was reduced in the 1st year postfire, but increased over the following 7 years, suggesting that decreased competition may have enhanced western larch growth [109].
Early Regeneration: Fires that expose mineral soil and reduce competition, especially on north-facing slopes, favor rapid and abundant western larch regeneration and dominance [2,114]. Western larch usually establishes in the 1st season after fire [2], and as much as 5 inches (13 cm) of 1st year postburn seedling growth has been reported after spring, summer, and fall burning of white fir sites on Wallowa-Whitman National Forest, Oregon [104]. In the Flathead National Forest of northwestern Montana, western larch began colonizing both wildfire and prescribed burn sites during the 1st year postfire [133,145]. Burned seedbeds from underburning in shelterwood units in Idaho produced 3 to 7 times more western larch seedlings than unburned seedbeds [136]. After clearcutting in northern Idaho subalpine fir-Engelmann spruce-menziesia type, western larch stocking was 20% on clearcuts that were burned and scarified, compared to 8% stocking on unburned clearcuts [23]. After fires in 1910 and 1919 in Coeur d'Alene National Forest, Idaho, western larch had restocked up to 200 seedlings per acre (500 seedlings/ha) on the north aspect of the study area by the fall of 1923. Western larch seedlings accounted for 83% of conifer seedlings present on all slopes and 88% of those on the north-facing slope [84]. Overstocking may result on some sites if too much mineral soil is exposed [37,67,114,123].
Old skid trails often support high densities of western larch seedlings, but the compacted soil does not allow trees to grow as well as on other sites. Good sites for potential for western larch establishment decrease as regeneration of a burned site progresses [2].
Latham and others [86] found that in general, fires that resulted in open sites, relatively free of vegetation, with full sun, moving shade, and a mineral soil seed bed favored the development of western larch forests. In these conditions, western larch seedlings were generally able to establish quickly and grow taller than other vegetation. Where tree establishment was delayed, however, shrubs were able to establish and suppress western larch.
Competition and Succession: Following fire, western larch must establish rapidly. Insufficient sunlight or exposed mineral soil will delay western larch establishment, allowing development of shrubs or more shade-tolerant tree species [2,148]. If the area does not burn again, shade will prevent western larch regeneration, and other species will eventually replace western larch [85,116]. Generally, stand-replacing fires favor western larch over its competitors because western larch is most likely to survive and postfire survivors will provide an onsite seed source, while less fire-resistant competitors must rely on offsite sources or unburned islands [1,10,135]. Low to moderate intensity fires thin out competitors [10,30]. The species may dominate the area for 150-350 years in the absence of fire [10,135].
Western larch and lodgepole pine are early seral species that often compete in the same recently burned areas. In general, lodgepole pine performs better on drier or more exposed sites [135]. Due to western larch's later age of 1st seed production and longer lifespan, it may be favored over lodgepole pine on sites that burn less frequently [138]. Western larch-lodgepole pine stands in grand fir sites of northwestern Montana with as little as 10% western larch overstory can eventually be dominated by western larch [1]. In Coram Experimental Forest in northwestern Montana, single high intensity burns in western larch-Douglas fir habitat thinned the overstory and favored regeneration of western larch, Douglas-fir and lodgepole pine, while multiple severe burns tended to promote lodgepole pine [138]. Western larch benefits from periodic surface fires that kill competing shade-tolerant conifers [15].
Absence of fire: Prior to 1900, fire maintained western larch as a dominant seral species in various habitats [3,7]. Lack of periodic fires may limit western larch regeneration [37]. Fire suppression in last century has favored thickets of suppressed shade-tolerant conifers [4,7,10], which result in a decline in the vigor of all trees [10]. These sites are at risk of high-intensity wildfires [3,4,60]. Large areas in and around the western larch habitat type are now characterized by such crowded and stagnant stands [10], and fire suppression has been linked to the decline of western larch habitat in Idaho, Montana, Oregon, and Washington [10,30,60,91].
In Bear Creek Canyon of the Bitterroot Mountains, Montana, where the old western larch are prevalent and younger ones less abundant and dwarf mistletoe has infected most trees, the species is near extinction due to lack of fire or other disturbance [91]. Remaining old-growth ponderosa pine-western larch habitat in Pattee Canyon near Missoula, Montana, has a thick understory of Douglas-fir saplings and pole-sized trees. This understory could provide ladder fuels, resulting in a crown fire [60]. If fire does not occur before the remaining trees die in these areas, or if ladder fuels create a crown fire that burns intensely enough to kill the remaining trees, the western larch seed source may be eliminated. However, if a seed source remains after fire, western larch may thrive in the postfire mineral seedbed with reduced competition.
Breeding system: Western larch is monoecious with both staminate and ovulate cones distributed throughout the crown [115,116].
Pollination: Western larch pollen is distributed by wind and is less abundant than that of other conifers. Owens [101] described the physiological details of pollination in western larch.
Seed production: Western larch cone production may begin as early as age 8 though it is unusual on trees less than 25 years old. Heavier crops usually begin at approximately 40 to 50 years of age and continue for 300 to 500 years [116,130]. Trees usually produce cones annually, but crop size varies with year and location; heavy cone crops occur every 5 years on average, with fair to poor crops in other years [115,121]. Shearer and Carlson [121] reported an annual average of 1,393 potential cones per tree over a 6-year period. Because western larch cones are borne throughout the crown, the size of the crop generally corresponds to the size of the crown [115,116,117]. Shearer and Kempf's [132] literature review indicated that the number of cones also increases with increased spacing of trees.
Western larch seeds are small and light, just 137,000 to 143,000 per pound (301,00-315,00/kg) [12,115,154]. On average each mature cone produces 39 seeds, but some may contain as many as 80, and mature stands of western larch may produce more than 0.5 million seeds per acre (1.2 million seeds/hectare) [115]. Roe [111] described a method for estimating the size of western larch seed crops up to 1 year in advance.
Viability of seeds typically increases with crop size and decreases with tree age [115]. Inviable seed results from lack of pollination, inviable pollen, lack of fertilization, later ovule abortion, or embryo abortion [102]. Over a 6-year period, Shearer and Carlson [121] found that 4% of potential seeds at the time of bud burst matured as filled seeds.
Seed dispersal: Most of western larch's small, light, long-winged seeds are distributed within 328 feet (100 m) of the parent. However, depending on wind conditions, they may be dispersed up to 820 feet (250 m) or more [116]. This distance is comparable to that of Engelmann spruce seeds, but is longer than Douglas-fir and subalpine fir [115]. Seed spread rate is considered moderate [154].
Seed banking: Western larch seeds are viable only until the year following fertilization [117].
Germination: Seeds of western larch germinate well on a variety of seedbeds and aspects [117], but Stoehr [147] found that germination and survival was greatest in mineral soil. In a synthesis of literature on northwestern trees, Minore [93] ranked western larch germination and survival in the highest category for mineral seedbeds, in the middle category for burned seedbeds, and in the lowest category for organic seedbeds. The ideal temperature for germination is 80ð Fahrenheit (27ð C), but germination can occur at temperatures as low as 65ð Fahrenheit (18ð C). Germination occurs at or above the soil surface. Natural stratification during winter results in rapid, complete germination. Spring-sown western larch seeds without stratification germinate slowly and erratically; some do not germinate until the following season [115]. Oswald [100] reported seed predation and shade both had negative effects on germination rates of western larch, though shading was not a significant factor. Shade appears to be more important as seedlings develop.
Seedling establishment/growth: On average 1 western larch seedling will establish for every 53 seeds produced and dispersed [127]. Seedlings grow rapidly and vigorously [115,154], averaging 2 inches (5 cm) of growth during the 1st season and 12 inches (30 cm) per year over the next 4 years. Western larch seedlings grow faster than all major associates except lodgepole pine, and the species grows faster than any other Rocky Mountain conifer until 100 years of age [12,115].
Site variation: Site requirements for establishment and growth of western larch seedlings are more specific than those for germination. Seedlings are well adapted to the mineral soil and sunlight of exposed seedbeds, such as those created by burning or mechanical scarification. They do not thrive in areas with undisturbed litter, humus, sod, or heavy root competition [12,54,115,116,117,123]. Overly dense stands slow growth. For the 1st few years shaded seedlings usually grow faster than those in full sunlight; thereafter, seedlings in full sunlight outgrow shaded seedlings. North, northwest, and northeast exposures and gentle to flat topography are best for seedling survival; high surface temperatures on south and west exposures may kill many seedlings [115].
Mortality: Seedling mortality is usually highest in the 1st season; losses after year 3 are minimal [115]. Biotic factors, such as fungi, birds, and rodents, cause the most 1st year seedling deaths early in the season, but drought is more detrimental after mid-July [115,117]. Newly germinated seedlings were killed by high soil-surface temperatures (>130ð Fahrenheit (54ð C)) in Montana, and these effects were most severe on western and southern exposures [117,122].
Asexual regeneration: Western larch does not reproduce by sprouts, but propagation by cuttings has been successful [115].
Western larch is the least shade tolerant conifer in its range [11,45,46,48,116]. As such, it is a seral species whose populations have been historically maintained by disturbances such as wildfire and glacial retreats [45,46,116,126] and is therefore usually found in even-aged stands [116]. It is an aggressive pioneer species after fire or other major disturbance [11,46,61,88] and competes best on moist sites [48,61]. In drier environments where fires are frequent, western larch may form a "fire climax" [152].
Western larch uses nitrogen more efficiently than evergreen trees, reducing its dependence on soil for nitrogen and increasing its effectiveness as a pioneer in disturbed, infertile habitats [56,149]. This aggressive pioneer quickly colonizes disturbed areas and grows rapidly, remaining taller than its associates for approximately 100 years [45,46,116,126]. Western larch's rapid height growth may indicate allocation of resources to early growth rather than early seed production, which would explain the species' relatively advanced age of 1st reproduction compared to other early successional species. Western larch extension growth was significantly greater than that of 6 other northwestern conifers. This characteristic and low shade tolerance were both associated with early successional species studied [152].
In the absence of disturbance, shade tolerant associates form understories that shade out future generations of western larch seedlings [116]. However, western larch's long lifespan and resistance to damage from fire and pathogens accounts for the presence of relict trees in late-successional stands that can repopulate the stand if fire or other disturbance removes competition and opens the canopy [45].
The currently accepted scientific name for western larch is Larix
occidentalis Nutt. (Pinaceae) [50,76,154].
Natural hybridization of western larch and alpine larch (Larix lyallii) has
been documented in the Carlton Ridge Research Natural Area and in the
Cabinet Mountains and Bitterroot Range of Montana, where the species are
sympatric. Usually, however, western larch and alpine larch are isolated by
elevation [26,27,31]. Carlson and Ballinger [28] reported that 1st generation western larch-alpine
larch crosses are viable. Carlson and others' [27] literature review reported successful crosses
of western larch with European larch (L. decidua) and with Japanese larch
(L. kaempteri).
Larix occidentalis, el Alerce americanu occidental[2] o, a cencielles, alerce occidental, ye una especie arbórea perteneciente a la familia de les pinacees, orixinaria de los montes de Norteamérica occidental, en Canadá nel sureste de la Columbia Británica y el suroeste d'Alberta, y nos Estaos Xuníos nel este de Washington, esti d'Oregón, norte d'Idaho y oeste de Montana.
Ye una gran conífera caducifolia que llega a 30-60 m d'altu, con un tueru d'hasta 1,5 m de diámetru. La coronación ye estrechamente cónica; les cañes llaterales de cutiu cayen. Los biltos son dimórficos, cola crecedera estremada en biltos llargos (típicamente 10-50 cm de llargu) y con poques yemes, y biltos curtios de namái 1-2 mm de llongura con una simple yema. Les acícules son de verde claru, 2-5 cm de llargu y bien delgaes; volver d'un mariellu brilloso na seronda, dexando los biltos pálidos de pardu anaranxáu desnudos hasta la primavera siguiente.
Crez a 500-2.400 msnm y ye bien tolerante al fríu, capaz de sobrevivir a temperatures ivernices d'hasta menos 50 °C. Namái crez en suelos bien drenaos, evitando los encharcaos.
Les granes son comida importante pa dalgunos páxaros, incluyendo les especies Carduelis pinus, Carduelis flammea y Loxia leucoptera.
Delles tribus indies beben un fervinchu de biltos nuevos pa tratar la tuberculosis y la larinxitis.[3] Los pueblos indíxenes solíen mascar goma producida pol árbol según comer el cambium y sap.[4]
La madera ye dura y perdurable, pero tamién flexible en tires fines y apreciar especialmente na construcción de yates; la madera usada pa esto ten de tar llibre de nuedos, y namái puede llograse d'árboles vieyos que fueron fradadurados de mozos pa esaniciar les cañes llaterales. Pequeños palos de alerce úsense llargamente pa faer valles rústiques.
La madera ye bien apreciada como lleña nel Noroeste del Pacíficu onde se-y llama de normal "Tamarack," anque ye una especie distinta al alerce oriental que ye al que suel llamase n'inglés Tamarack. La madera quedar con un golor duce y un distintivu ruiu.
El alerce occidental usar pa la producción de trementina.
Larix occidentalis foi descritu por Thomas Nuttall y espublizóse en The North American Sylva 3: 143, pl. 120. 1849. [5]
Larix: nome xenéricu que provién del términu llatín larix que significa "alerce, lárice".[6]
occidentalis: epítetu llatín que significa "d'occidente"
Larix occidentalis, el Alerce americanu occidental o, a cencielles, alerce occidental, ye una especie arbórea perteneciente a la familia de les pinacees, orixinaria de los montes de Norteamérica occidental, en Canadá nel sureste de la Columbia Británica y el suroeste d'Alberta, y nos Estaos Xuníos nel este de Washington, esti d'Oregón, norte d'Idaho y oeste de Montana.
Şimali Amerika nın qərb hissəsinin dağlarında 600-2300 m hündürlükdə, meşə zolağnda, kölgəli yamaclarda və çay vadilərində, çox vaxt qarışıq əkinlərdə bitir. Vətənində hündürlüyü 40-80 m-ə çatan ağacdır. Çətiri ensiz, piramidaldır. Budaqları qısa, üfüqi, tüklü olur, sonradan çılpaqlaşır, cavan zoğlarının rəngi sarımtıldan narıncıya dəyişir. Tumurcuqları qatranlı, saçaqlıdır. Uzunluğu 3-4 sm olan iynələri küt uclu, üstü yumru, hər iki tərəfdən 2 ağ kanallıdır. Dəstələrdə 15-40 ədəd yerləşir, qatran yolları yoxdur. Qozaları 6 mm-lik ağ tüklü saplaqda yerləşir, yumurtavarıdır, uzunluğu 2.5-3 və ya 5 sm-dir. Toxum ağımtıl, qonur qanadlı, qabıqları yumru, kənarları bütöv, üstü zərif tükcüklüdür. Şimali Amerikanın ən hündür qara şamıdır. Tez böyüyür, işıqsevəndir, qışadavamlı, quraqlığa davamsızdır. Yaxşı drenajlı, zəngin və rütubətli tropaqlarda yaxşı inkişaf edir. Uzunömürlüdür, 700 ilə qədər yaşayır. Qərbi Avropada 1880-ci ildən becərilir. Azərbaycan da Bakı şəhərində bu bitki dekorativ əlamətlərinə görə yeni salınan park və bağlarda rast gəlinir.
Деревья и кустарники СССР. т.3.1954; Флора Азербайджана. т.5. 1954; Azərbaycanın ağac və kolları. III cild. 1970; Azərbaycanın “Qırmızı” və “Yaşıl Кitabları”na tövsiyə olunan bitki və bitki formasiyaları. 1996; Azərbaycan florasının konspekti. I-III cildlər. 2005; 2006; 2008.
Şimali Amerika nın qərb hissəsinin dağlarında 600-2300 m hündürlükdə, meşə zolağnda, kölgəli yamaclarda və çay vadilərində, çox vaxt qarışıq əkinlərdə bitir. Vətənində hündürlüyü 40-80 m-ə çatan ağacdır. Çətiri ensiz, piramidaldır. Budaqları qısa, üfüqi, tüklü olur, sonradan çılpaqlaşır, cavan zoğlarının rəngi sarımtıldan narıncıya dəyişir. Tumurcuqları qatranlı, saçaqlıdır. Uzunluğu 3-4 sm olan iynələri küt uclu, üstü yumru, hər iki tərəfdən 2 ağ kanallıdır. Dəstələrdə 15-40 ədəd yerləşir, qatran yolları yoxdur. Qozaları 6 mm-lik ağ tüklü saplaqda yerləşir, yumurtavarıdır, uzunluğu 2.5-3 və ya 5 sm-dir. Toxum ağımtıl, qonur qanadlı, qabıqları yumru, kənarları bütöv, üstü zərif tükcüklüdür. Şimali Amerikanın ən hündür qara şamıdır. Tez böyüyür, işıqsevəndir, qışadavamlı, quraqlığa davamsızdır. Yaxşı drenajlı, zəngin və rütubətli tropaqlarda yaxşı inkişaf edir. Uzunömürlüdür, 700 ilə qədər yaşayır. Qərbi Avropada 1880-ci ildən becərilir. Azərbaycan da Bakı şəhərində bu bitki dekorativ əlamətlərinə görə yeni salınan park və bağlarda rast gəlinir.
Die Westamerikanische Lärche (Larix occidentalis) ist eine Pflanzenart aus der Gattung der Lärchen (Larix) in der Familie der Kieferngewächse (Pinaceae). Diese im westlichen Nordamerika heimische Lärchenart ist die größte aller Lärchenarten; sie stellt an ihren Naturstandorten einen wichtigen Holzlieferanten dar.
Die Westamerikanische Lärche ist ein sommergrüner Baum; der in seiner Heimat Wuchshöhen von etwa 60 Metern bei Stammdurchmessern von bis zu 1,5 Meter erreicht. In Mitteleuropa wird sie dagegen meist nur 25 Meter hoch. Die Baumkrone ist in der Jugend schmal kegelförmig, im Alter breiter werdend. In Forstpflanzungen wird der größte Teil des Stammes astrein, was den Wert des Nutzholzes steigert. Während die Hauptäste waagrecht bis leicht aufwärts gerichtet stehen, sind die Seitenzweige oft hängend.
Umfassende Erkenntnisse über das Wurzelsystem liegen nicht vor. Jedoch kann die Pfahlwurzel in lockeren Böden Tiefen von mehr als 2 Metern erreichen. In eher lichten Beständen reichen die Lateralwurzeln oft 6 Meter und mehr über die Kronentraufe hinaus.[1]
In den ersten zehn Lebensjahren ist die Westamerikanischen Lärche die schnellstwüchsige aller in den Nördlichen Rocky Mountains vorkommenden Nadelbaumarten.[2]
Die purpurgraue Borke des Stammes bildet tiefe und weite Risse; die stehenbleibenden Streifen sind schuppig gerandet. Mit ihrer sehr dicken Borke und Erneuerungsknospen, die nach einem Brand zerstörte Organe ersetzen können,[3] schützt sich der Baum vor Schäden durch Waldbrände. An älteren Bäumen wird die Rinde bis 15 cm dick. Die Rinde der dicken Zweige ist hell orangebraun. Die Rinde junger Zweige ist zunächst noch behaart, verliert die Behaarung jedoch bereits im Verlauf des ersten Jahres fast völlig.
Die Knospen sind dunkelbraun. Die dünnen nadelförmigen Blätter sind 3 bis 5 cm lang und beiderseits hell grasgrün. Sie sind etwa 0,6 bis 0,8 mm breit und stehen zu 15 bis 30 in rosettenförmigen Büscheln. Im Herbst färben sich die Nadeln hellgelb, bevor sie abfallen.
Die Westamerikanische Lärche ist einhäusig getrenntgeschlechtig (monözisch), trägt also männliche und weibliche Zapfen am gleichen Baum. Der Pollen misst 71 bis 84 µm im Durchmesser. Die weiblichen Zapfen sind eiförmig bis zylindrisch; sie sind purpurfarben und 2 bis 4 cm lang. Der einzelne Zapfen trägt etwa 40 bis 80 Zapfenschuppen, die im Sommer gelb- bis orangefarben sind. Die Zapfenschuppen sind lang vorragend mit abstehenden oder zurückgeschlagenen Spitzen. Zur Reifezeit im Herbst und im frühen Winter verfärben sich die Zapfen braun und entlassen etwa 75 bis 80 Samen, wovon die Hälfte nicht voll entwickelt sind.[1] Die abgestorbenen Zapfen bleiben oft noch jahrelang am Baum hängen und sind dann dunkelgrau. Bereits in einem Alter von nur acht Jahren setzt eine spärliche Samenproduktion ein; ab einem Alter von etwa 25 Jahren kommen alle drei bis sechs Jahre Vollmasten vor.
Die rotbraunen Samen sind etwa 3 mm groß, zusammen mit dem Flügel sind sie knapp 1 cm lang. Die Tausendkornmasse beträgt etwa 2,7 g. Wie bei allen Lärchen erfolgt die Verbreitung der geflügelten Samen durch den Wind (Anemochorie); Weiten von bis zu 250 m können so erreicht werden. Winterkälte bzw. Stratifikation erhöhen die Keimrate deutlich.[1]
Die Samen der Westamerikanischen Lärche keimen epigäisch. An den Naturstandorten findet die Keimung zur Zeit der Schneeschmelze (Ende April bis Anfang Juni) statt, meist 1 bis 2 Wochen früher als bei wichtigen konkurrierenden Baumarten. Der Sämling erreicht im ersten Jahr eine Höhe von etwa 5 Zentimetern.[2]
Die Chromosomenzahl der Westamerikanischen Lärche beträgt 2n = 24.
Die Westamerikanische Lärche ist nahe der Westküste Nordamerikas im kanadischen British Columbia sowie in den US-Bundesstaaten Oregon, Washington, Idaho und Montana heimisch. Sie wächst dort in Höhenlagen von 500 bis 2200 m. Besonders zahlreich sind die Vorkommen im östlichen Kaskadengebirge in Washington sowie in den Blue Mountains (Washington und Oregon).
In Mitteleuropa ist sie sehr selten gepflanzt und wohl nur in größeren Sammlungen zu finden.
Die Westamerikanische Lärche ist winterhart und verträgt Kälte bis etwa −50 °C. Sie bevorzugt feuchte, aber nicht staunasse Böden, gedeiht aber auch auf trockeneren Standorten. Sie ist extrem lichtbedürftig; jede Lichtkonkurrenz ist schädlich. Natürliche Verjüngung erfolgt eben aus diesem Grund nicht im Schatten.[1]
Aus europäischer Sicht wurde die Westamerikanische Lärche erstmals von Meriwether Lewis und William Clark auf ihrer von 1803 bis 1806 dauernden Expedition durch das westliche Nordamerika, der Lewis-und-Clark-Expedition, entdeckt. Lewis und Clark beschrieben die von ihnen entdeckte Lärche 1806, sahen sie jedoch noch nicht als eigene Art an. Erst der englische Botaniker Thomas Nuttall stufte sie 1849 als eigene Art Larix occidentalis ein und ist damit der Autor der heute gültigen Erstbeschreibung.[4]
Das Holz der Westamerikanischen Lärche ist hart und witterungsbeständig. Es ist relativ geradfaserig mit einem strohfarbenen Splint und einem kastanienbraunen Farbkern. Das Holz ist nur wenig spröde, lässt sich leicht spalten und hat eine ölige wirkende Oberfläche. Die Rohdichte von frischem Holz beträgt etwa 0,5 g/cm³.[1] In Nordamerika ist es ein begehrtes Holz für den Bau von Yachten; daneben wird es unter anderem als Bauholz, für Eisenbahnschwellen und Zäune, aber auch als Brennholz verwendet.
Das Harz des Baumes härtet an der Luft und ist zuckerhaltig; einheimische Indianer haben es wie Kaugummi verwendet. Heute wird aus dem Baumharz „venezianisches Terpentin“ gewonnen.
Das höchste stehende Exemplar mit einer Höhe von 58,5 m und einem Stammdurchmesser von 1,38 m (Stand 2000) steht im Umatilla National Forest in Oregon. Das Exemplar mit dem größten Stammvolumen von 83 m³ ist der Seeley Lake Giant im Lolo National Forest (Nähe Paxton Camp) in Montana; dieser Baum ist 49,4 m hoch bei einem Stammdurchmesser von 2,21 m.[5]
Das älteste Exemplar soll gemäß einer Baumringzählung an einem Baumstumpf nahe Cranbrook in British Columbia gestanden und ein Alter von 920 Jahren aufgewiesen haben.[6]
Das vermutlich größte aller in Großbritannien gepflanzten Exemplare steht in Kyloe Woods, Northumberland und hat bislang eine Wuchshöhe von 33 Metern erreicht.[7]
Der aus forstwirtschaftlicher Sicht schädlichste Baumschmarotzer auf der Westamerikanischen Lärche ist die parasitische Pflanze Arceuthobium laricis (englisch „Larch dwarf mistletoe“) aus der Gattung Zwergmisteln (Arceuthobium) in der Familie der Sandelholzgewächse, eine relativ nahe Verwandte der Misteln. Sie kann bereits junge Bäume im Alter von 3 bis 7 Jahren befallen und schädigt diese unter anderem durch Abtöten der Baumspitze, aber auch durch die Begünstigung des Eintritts anderer Baumkrankheiten und Insekten. Die Früchte dieser Baumschmarotzerart werden mit hoher Geschwindigkeit ausgeworfen und können dadurch bis zu 14 Meter weit weg vom befallenen Baum landen. Dieser Parasit kommt in etwa 80 % der natürlichen Bestände vor. Folge ist unter anderem ein erheblicher Zuwachsrückgang sowie Hexenbesen.[1]
Bedeutende Baumkrankheiten der Westamerikanischen Lärche sind der vorzeitige Nadelabwurf, verursacht durch die Pilzarten Hypodermella laricis[8] und durch Fomitopsis officinalis, einen Vertreter aus der Familie der Baumschwammverwandten (Fomitopsidaceae). Ein weiterer schädlicher Pilz ist der Kiefernfeuerschwamm (Phellinus pini) aus der Ordnung der Borstenscheiblingsartigen (Hymenochaetales), im Englischen „red ring rot“ genannt. Es gibt noch weitere Pilzarten wie Encoeliopsis laricina, die den Baum befallen, diese verursachen jedoch forstwirtschaftlich viel weniger Schäden.
Die aus Europa eingeschleppte Lärchenminiermotte (Coleophora laricella), die die jungen Blätter frisst, ist ein problematischer Schädling geworden. Sie wurde in den Nördlichen Rocky Mountains 1957 erstmals beobachtet und hat sich mittlerweile über praktisch alle Lärchenwälder verbreitet. Einheimische und eingeführte Parasiten halten die Lärchenminiermotte einigermaßen in Schach; der Blattfraß reduziert das Baumwachstum, verursacht aber eine nur geringe Mortalitätsrate unter den Bäumen. Auch die Schmetterlingsart Choristoneura freemani aus der Familie der Wickler (Tortricidae) ist ein bedeutender Schädling. Sie richtet hohen Schaden an, da oft der Leittrieb stark geschädigt wird.
Weitere Insekten, die die Westamerikanische Lärche schädigen, sind die Pristiphora erichsonii aus der Familie der Echten Blattwespen (Tenthredinidae) sowie Zeiraphera improbana, eine weitere Schmetterlingsart aus der Familie der Wickler (Tortricidae). Diese beiden Arten treten sporadisch auf und können dann hohen Schaden anrichten. Zu den weiteren, aber weniger gefährlichen Schädlingen zählen Anoplonyx occidens (englisch „western larch sawfly“), Anoplonyx laricivorus (englisch „two-lined larch sawfly“) sowie Semiothisa sexmaculata incolorata, ein Vertreter der Familie der Spanner (Geometridae).
Borkenkäfer zählen zu den weniger bedeutenden Schädlingen der Westamerikanischen Lärche. Bisweilen attackiert Dendroctonus pseudotsugae geschwächte Bäume. Auch die Buchdruckerart Ips plastographus, die Splintkäferart Scolytus laricis und die Schmetterlingsart Nepytia canosaria aus der Familie der Spanner schädigen den Baum.[2]
Die Samen der Westamerikanischen Lärche sind eine begehrte Futterquelle für Vogelarten wie den Fichtenzeisig (Carduelis pinus), den Birkenzeisig (Carduelis flammea) und den Bindenkreuzschnabel (Loxia leucoptera).
Die ausgesprochen dicke Rinde bietet dem ausgewachsenen Baum einen guten Schutz vor Waldbränden. Die Westamerikanische Lärche ist als ausgewachsener Baum die gegenüber Waldbränden widerstandsfähigste Art der Nördlichen Rocky Mountains.[2] Die Samen der Westamerikanischen Lärche sind nach Waldbränden besonders keimfreudig.
Die Westamerikanische Lärche hybridisiert bisweilen mit der Felsengebirgslärche (Larix lyallii).
Die Westamerikanische Lärche (Larix occidentalis) ist eine Pflanzenart aus der Gattung der Lärchen (Larix) in der Familie der Kieferngewächse (Pinaceae). Diese im westlichen Nordamerika heimische Lärchenart ist die größte aller Lärchenarten; sie stellt an ihren Naturstandorten einen wichtigen Holzlieferanten dar.
Larix occidentalis (лат. Larix occidentalis) — быдмассэзлӧн пожум котырись лисвень увтырын торья вид. Лисвеньыс быдмӧ 30–60метра вылына да овлӧ 1.5 метра кыза диаметрын. Лисвень пантасьӧ Ойвыв Америкаын.
The western larch (Larix occidentalis) is a species of larch native to the mountains of western North America (Pacific Northwest, Inland Northwest); in Canada in southeastern British Columbia and southwestern Alberta, and in the United States in eastern Washington, eastern Oregon, northern Idaho, and western Montana. It is the most productive of the three species of larch native to North America.[2][3]
The tree is a large deciduous conifer reaching 30 to 60 meters (98 to 197 feet) tall, with a trunk up to 1.5 m (4 ft 11 in) diameter; the bark ranges from orangish to purplish brown.[4] The crown is narrow conic; the main branches are level to upswept, with the side branches often drooping. The shoots are dimorphic, with growth divided into long shoots (typically 10 to 50 centimeters (4 to 20 in) long) and bearing several buds, and short shoots only 1 to 2 millimeters (1⁄32 to 3⁄32 in) long with only a single bud. The leaves are needle-like, light green, 2 to 5 cm (3⁄4 to 2 in) long, soft[4] and very slender; they turn bright yellow in the fall, leaving the pale orange-brown shoots bare until the next spring.[5]
The seed cones are ovoid-cylindric, 2 to 5 cm (3⁄4 to 2 in) long, with 40 to 80 seed scales; each scale bearing an exserted 4 to 8 mm (3⁄16 to 5⁄16 in) bract. The cones are green[4] to reddish purple when immature, turning brown and the scales opening flat or reflexed to release the seeds when mature, four to six months after pollination. The old cones commonly remain on the tree for many years, turning dull gray-black.[5]
Individual specimens can live centuries, even up to a millennium.[4] The largest known specimen is about 1,000 years old, 50 m (160 ft) tall and over 2 m (7 ft) in diameter with a 10 m (34 ft) crown, located at Seeley Lake, Montana.[4][5]
Western larch grows almost exclusively in the drainage of the Columbia River, from the east of the Cascade Range to the west of the Continental Divide.[4] It covers the regions from around Kamloops, British Columbia, to Weiser, Idaho, and Central Oregon.[4] It appears on ranges including the Blue Mountains and others in southeast BC and northwest Montana, usually on moist slopes up to 1,800 m (5,900 ft) above sea level.[4] It can grow from elevations between 500 and 2,400 m (1,600 and 7,900 ft) and is very cold tolerant, able to survive winter temperatures down to about −50 °C (−58 °F). It only grows on well-drained soils, unable to thrive on waterlogged ground.[6]
Western larch grows more quickly than many associated trees, as it needs to because larch is shade intolerant. With its thick bark, nonflammable foliage and protective cones, the species is very fire resistant.[4] In the late 20th century, after wildfires had been suppressed for almost a century, larches at Seeley Lake and Glacier National Park were endangered by major fires enabled by fuel ladder; normally smaller fires would have depleted the fuel.[4] In more recent years, many smaller fires have been allowed to take their course.[4]
Grouse browse the tree's leaves and buds.[7] The seeds are an important substitute winter food for some birds, notably the pine siskin but also the redpoll, and white-winged crossbill. This is frequently during times when other conifer cones that are a more preferred diet are in short supply.[8][9][10] Woodpeckers utilize the heart rot of older specimens to make openings, which are used by various small animals.[4]
In 2010, the Government of British Columbia implemented an assisted migration program of western larch to a new habitat in northern British Columbia, about 1000 kilometers north of its current range.[11] Assisted migration of Canadian forests had been proposed as an adaptation measure in response to climate change. Indeed, as average temperatures rise, the optimal climate conditions for trees species are also moving North. Research had shown that western larch trees have no trouble growing in northern BC, an area whose climatic conditions are predicted to match the western larch's historical range by 2030.[3]
British Columbia started seeding western larch trees in northern BC in the early 2010s. This was the first assisted migration program for a North American tree. The western larch was selected for because of its significant commercial importance and the fear that climate change and parasites such as the mountain pine beetle would considerably diminish its supply. To pre-empt opposition from biologists and other groups, the government avoided making public consultation on the program. Instead, they framed the policy as an introduction of a non-exotic species to a similar environment, and implemented the program through the province's existing legal and regulatory framework.[3]
Foresters in the United States have also initiated "experimental treatments" of larch-dominated national forests in Montana.[12] However, if some "aggressively warming climate scenarios" actually unfold, foresters will need to let go of any expectations of helping this species maintain a presence south of the Canadian border.[13]
Indigenous peoples applied the resinous gum to injuries and chewed it to treat sore throat.[4] Some also ate the cambium and sap;[14] the Kutenai and Salish peoples of Montana in particular collected the sap.[4] A medicinal tea was made from the bark or foliage.[4] Some Plateau Indian tribes drank an infusion from the young shoots to treat tuberculosis and laryngitis.[15]
The sweetish galactan of the sap can be made into baking powder and medicine.[7] An extract of the tree is sold as a health supplement.[4] The water-soluble arabinogalactan is used in food, medicine, ink, and paint.[4]
The wood is tough and durable, but also flexible in thin strips, and is particularly valued for yacht building; wood used for this must be free of knots, and can only be obtained from old trees that were pruned when young to remove side branches. Small larch poles are widely used for rustic fencing.[16] The wood is highly prized as firewood in the Pacific Northwest where it is often called "tamarack," although it is a different species than the tamarack larch. The wood burns with a sweet fragrance and a distinctive popping noise.[17]
Western larch is used for the production of Venice turpentine.[18]
Media related to Larix occidentalis (category) at Wikimedia Commons
The western larch (Larix occidentalis) is a species of larch native to the mountains of western North America (Pacific Northwest, Inland Northwest); in Canada in southeastern British Columbia and southwestern Alberta, and in the United States in eastern Washington, eastern Oregon, northern Idaho, and western Montana. It is the most productive of the three species of larch native to North America.
La okcidenta lariko (Larix occidentalis) esta larikospecio indiĝena en la montaro de okcidenta Nordameriko, en Kanado en sudorienta Brita Kolumbio kaj sudokcidenta Alberto, kaj en Usono en orienta Vaŝingtonio, orienta Oregono, norda Idaho kaj okcidenta Montano.
Ĝi estas granda decidua konifero atinganta alton de 30-60 m, trunke laŭdiametre ĝis 1,5 m. La plej granda konata okcidenta lariko estas 49,4 m alta kaj 2,21 cm dika, situanta en Nacia Arbaro Lolo, Montano. La arbokrono estas mallarĝe konusforma; la precipaj branĉoj estas horizontalaj al leviĝantaj, kun la flankbranĉoj ofte pendantaj. La ŝosoj estas duformaj, kun kresko dividita en longajn ŝosojn (tipe 10-50 cm longajn) kaj portantajn plurajn burĝonojn, kaj mallongajn ŝosojn nur 1-2 mm longajn kun nur ununura burĝono. La folioj estas pinglo-similaj, helverdaj, 2-5 cm longaj, kaj tre gracilaj; ili fariĝas helflavaj en la aŭtuno, lasante la palajn oranĝ-brunajn ŝosojn nudajn ĝis la venonta printempo. La strobiloj estas ovoidaj-cilindraj, 2–5 cm longaj, kun 40–80 semskvamoj; ĉiu skvamo portas eltranĉatan brakteon de 4–8 mm. La strobiloj estas ruĝaj kiam nematuraj, fariĝante brunaj kaj liberigante la semojn kiam ili estas maturaj, 4–6 monatojn post la polenado. La maljunaj strobiloj kutime restas sur la arbo dum multaj jaroj, estiĝante obtuze griznigraj. Ĝi kreskas je altitudoj de 500-2 400 m, kaj estas tre malvarm-tolerema, kapabla postvivi vintrotemperaturojn malsupren al proksimume −50 °C. Ĝi nur kreskas sur bon-drenitaj grundoj, evitante akvosaturatan grundon. La semoj estas grava manĝaĵo por kelkaj birdoj, precipe la pinkardelo, la flamkardeloj kaj la rubanda krucbekulo.
Iuj indiĝenaj popoloj de Pacifika Nordokcidento trinkis infuzaĵon de la junaj ŝosoj por trakti tuberkulozon kaj laringiton [1].
La ligno estas dura kaj daŭrema, sed ankaŭ fleksebla en maldikaj strioj, kaj estas precipe aprezata por jaĥto-konstruado; ligno uzata por tio devas esti libera de nodoj, kaj povas nur esti akirata el maljunaj arboj kiuj estis pritondataj kiam junaj por forigi flankobranĉojn. Malgrandaj larikstangoj estas vaste uzataj por rustikaj bariloj.
La okcidenta lariko estas uzata por produkti terebintinon. La ligno estas tre aprezata kiel brulligno en Pacifika Nordokcidento kie ĝi estas ofte nomita "tamarack", kvankam temas pri malsama specio ol la orienta lariko. La ligno brulas kun dolĉa parfumo kaj karakteriza kreva bruo.
La indiĝenaj popoloj estis uzantaj la rezinon por maĉi ĝin kaj estis manĝantaj la internan ŝelon kaj la sevon [2].
La okcidenta lariko (Larix occidentalis) esta larikospecio indiĝena en la montaro de okcidenta Nordameriko, en Kanado en sudorienta Brita Kolumbio kaj sudokcidenta Alberto, kaj en Usono en orienta Vaŝingtonio, orienta Oregono, norda Idaho kaj okcidenta Montano.
Larix occidentalis, el alerce americano occidental[2] o, simplemente, alerce occidental, es una especie arbórea perteneciente a la familia de las pináceas, originaria de las montañas de Norteamérica occidental, en Canadá en el sureste de la Columbia Británica y el suroeste de Alberta, y en los Estados Unidos en el este de Washington, este de Oregón, norte de Idaho y oeste de Montana.
Es una gran conífera caducifolia que llega a 30-60 m de alto, con un tronco de hasta 1,5 m de diámetro. La coronación es estrechamente cónica; las ramas laterales a menudo caen. Los brotes son dimórficos, con el crecimiento dividido en brotes largos (típicamente 10-50 cm de largo) y con pocas yemas, y brotes cortos de solo 1-2 mm de largo con una simple yema. Las acículas son de verde claro, 2-5 cm de largo y muy delgadas; se vuelven de un amarillo brillante en el otoño, dejando los brotes pálidos de pardo anaranjado desnudos hasta la primavera siguiente.
Crece a 500-2.400 msnm y es muy tolerante al frío, capaz de sobrevivir a temperaturas invernales de hasta menos 50 °C. Solo crece en suelos bien drenados, evitando los encharcados.
Las semillas son comida importante para algunos pájaros, incluyendo las especies Carduelis pinus, Carduelis flammea y Loxia leucoptera.
Algunas tribus indias beben una infusión de brotes jóvenes para tratar la tuberculosis y la laringitis.[3] Los pueblos indígenas solían mascar la goma producida por el árbol así como comer el cambium y la savia.[4]
La madera es dura y perdurable, pero también flexible en tiras finas y se la aprecia especialmente en la construcción de yates; la madera usada para esto debe estar libre de nudos, y solamente puede obtenerse de árboles viejos que fueron podados de jóvenes para eliminar las ramas laterales. Pequeños palos de alerce se usan ampliamente para hacer vallas rústicas.
La madera es muy apreciada como leña en el Noroeste del Pacífico donde se le llama normalmente "Tamarack," aunque es una especie diferente al alerce oriental que es al que suele llamarse en inglés Tamarack. La madera se queda con un olor dulce y un distintivo ruido.
El alerce occidental se usa para la producción de trementina.
Larix occidentalis fue descrito por Thomas Nuttall y publicado en The North American Sylva 3: 143, pl. 120. 1849.[5]
Larix: nombre genérico que proviene del término latíno larix que significa "alerce, lárice".[6]
occidentalis: epíteto latíno que significa "de occidente"
Larix occidentalis, el alerce americano occidental o, simplemente, alerce occidental, es una especie arbórea perteneciente a la familia de las pináceas, originaria de las montañas de Norteamérica occidental, en Canadá en el sureste de la Columbia Británica y el suroeste de Alberta, y en los Estados Unidos en el este de Washington, este de Oregón, norte de Idaho y oeste de Montana.
Lännenlehtikuusi (Larix occidentalis) on pohjoisamerikkalainen lehtikuusilaji. Se voi risteytyä lyallinlehtikuusen kanssa.
Lännenlehtikuusi kasvaa tavallisesti noin 20–50 metriä korkeaksi. Vanhin tunnettu yksilö on 920-vuotias.
Lännenlehtikuusta kasvaa Montanan, Idahon, Washingtonin ja Oregonin alueilla noin 600–2 100 metrin korkeudella. Suomessa Punkaharjulle on perustettu viljelmä, jolla kasvaa enää vain kaksi lännenlehtikuusta.
Puun pihkaa on käytetty purukumina. Sillä on myös terveyttä edistäviä ominaisuuksia. Lännenlehtikuusesta uutetaan myös siirappia.
Lännenlehtikuusi (Larix occidentalis) on pohjoisamerikkalainen lehtikuusilaji. Se voi risteytyä lyallinlehtikuusen kanssa.
Lännenlehtikuusi kasvaa tavallisesti noin 20–50 metriä korkeaksi. Vanhin tunnettu yksilö on 920-vuotias.
Le Mélèze de l'Ouest (Larix occidentalis) est une espèce de mélèze du genre Larix et de la famille des Pinaceae originaire du nord-ouest de l'Amérique du Nord.
L'arbre est présent au Canada au sud-est de la Colombie-Britannique et au sud-ouest de l'Alberta mais aussi aux États-Unis dans l'est des États de l'Oregon et de Washington, au nord de l'Idaho et à l'ouest du Montana. L'arbre qui supporte très bien le froid (jusque −50 °C) pousse à des altitudes comprises entre 500 et 2400 mètres. Il apprécie les terrains bien drainés non gorgés d’eau.
L'arbre est un conifère caduc qui peut atteindre 30 à 60 mètres de haut et donc le tronc atteint à la base un diamètre d'un mètre cinquante. La forme de l'arbre est conique et ses branches principales sont dirigées vers le haut alors que leurs ramifications retombent. Les aiguilles sont d'un vert clair, longues de 2 à 5 cm. Elles deviennent jaunes en automne et deviennent brun-orangé durant l’hiver avant de tomber pour laisser la place aux nouvelles aiguilles au printemps. Les cônes sont ovoïdes, de 2 à 5 cm de long, possèdent 40 à 80 écailles. De coloration rouge lorsqu'ils sont immatures, ils virent ensuite au brun une fois mature. Les écailles s'ouvrent 4 à 6 mois après la pollinisation pour libérer leurs graines. Les vieux cônes restent parfois plusieurs années sur l'arbre en se colorant en gris-noir. Les graines sont importantes pour l’alimentation de nombreux oiseaux comme le tarin des pins, le sizerin flammé et le bec-croisé bifascié.
Le bois est solide et durable. Il est flexible en fines découpes. Il est apprécié dans la construction navale lorsqu’il provient de vieux arbres dépourvus de nœuds. Il est également utilisé pour faire des clôtures en bois. Le bois est très apprécié en tant que combustible dans les régions du nord-ouest du continent américain. Les Amérindiens se nourrissaient du cambium de l'arbre et mâchaient la sève de l’arbre comme du chewing-gum[1].
L'arbre est également utilisé pour produire de la térébenthine de Venise.
Le Mélèze de l'Ouest (Larix occidentalis) est une espèce de mélèze du genre Larix et de la famille des Pinaceae originaire du nord-ouest de l'Amérique du Nord.
Risalerki er stórvaxnasta lerkitegundin. Það er einstofna tré með reglulega krónu og vex í fjöllum í norðvesturhluta Bandaríkjanna og í suðurhluta Bresku Kólumbíu. Það vex aðallega í Klettafjöllum en t.d. líka í Fossafjöllum. Það verður vanalega 30 til 55 metrar fullvaxið en getur náð rúmum 60 metrum.[1]
Lítil reynsla er af því á Íslandi. Hugsanlega má finna megi kvæmi innan útbreiðslusvæðis risalerkis sem geta lifað og vaxið nægilega vel á Íslandi til að þau nýtist a.m.k. í trjárækt eða skógrækt.[2] Risalerki hefur svipaða aðlögun að veðurfari og evrópulerki, þ.e. vex yfirleitt of lengi fram eftir hausti, en er mun beinvaxnara þrátt fyrir það. Virðist það þó vera viðkvæmt fyrir bæði nála- og átusjúkdómum hérlendis, sem evrópulerki er ekki. [3]
Risalerki er stórvaxnasta lerkitegundin. Það er einstofna tré með reglulega krónu og vex í fjöllum í norðvesturhluta Bandaríkjanna og í suðurhluta Bresku Kólumbíu. Það vex aðallega í Klettafjöllum en t.d. líka í Fossafjöllum. Það verður vanalega 30 til 55 metrar fullvaxið en getur náð rúmum 60 metrum.
Il Larice occidentale (Larix occidentalis) è una specie di larice nativa delle montagne dell'ovest del Nord America, sia in Canada, nelle province della Columbia Britannica e dell'Alberta, che negli Stati Uniti, nelle zone orientali di Washington ed Oregon, nonché nel nord dell'Idaho e ovest del Montana.
È una conifera di grandi dimensioni, in grado di raggiungere altezze comprese fra i 30 ed i 60 metri, con un diametro del tronco talvolta superiore al metro e mezzo. La chioma è pressoché conica; i rami principali partono dal livello del terreno, quelli laterali risultano spesso pendenti. I germogli, come in tutte le specie del genere Larix, si presentano dimorfici, con una netta differenziazione in macroblasti, tipicamente lunghi 10–50 cm e ricoperti da un gran numero di gemme, e brachiblasti lunghi 1–2 mm con una singola gemma apicale. Le foglie sono aghiformi, verde chiaro, lunghe 2–5 cm e molto sottili; diventano gialle in autunno prima dell'abscissione, lasciando i pallidi rametti bruno-arancioni spogli fino alla primavera successiva.
I coni sono cilindrico-ovoidali, lunghi 2–5 cm, con 40 od 80 scaglie, ognuna recante una brattea di 4–8 mm. Di colore rosso quando immaturi, diventano bruni con il passare del tempo e le scaglie si aprono o ripiegano per rilasciare i semi ad avvenuta maturità, a 4 o 6 mesi dall'impollinazione. i vecchi coni tipicamente rimangono sul ramo di origine per diversi anni, diventando di un grigio molto fosco. I semi sono un'importante fonte di cibo per molti uccelli, in particolare Carduelis pinus e Loxia leucoptera.
La specie cresce fra i 500 ed i 2400 metri di altitudine, ed è estremamente resistente al freddo, risultando in grado di sopravvivere a temperature invernali inferiori ai -50 gradi. Cresce solo su suoli ben drenati, evitando i terreni acquitrinosi.
Il legno prodotto da questa specie è resistente e durevole, ma anche flessibile se ridotto in fogli sottili, ed è particolarmente ricercato per la costruzione di yacht; il legno utilizzato per questo scopo deve essere privo di nodi, e può essere perciò ottenuto solo da alberi particolarmente anziani potati in giovane età allo scopo di rimuovere i rami bassi. Il legno del larice occidentale è molto apprezzato come combustibile nel nord-est del Pacifico; la sua combustione produce un ottimo profumo oltre che un caratteristico crepitio.
Il Larice occidentale (Larix occidentalis) è una specie di larice nativa delle montagne dell'ovest del Nord America, sia in Canada, nelle province della Columbia Britannica e dell'Alberta, che negli Stati Uniti, nelle zone orientali di Washington ed Oregon, nonché nel nord dell'Idaho e ovest del Montana.
Vakarinis maumedis (lot. Larix occidentalis) – pušūnų spygliuotis medis, priskiriamas pušinių (Pinaceae) šeimos, maumedžių (Larix) genčiai.
Savaime auga Šiaurės Amerikos vakarinėje dalyje - Kanados Britų Kolumbijos provincijos pietryčiuose, Albertos provincijos pietvakariuose, bei JAV šiaurinėje Aidaho, rytų Oregono, vakarinėje Montanos, rytinėje Vašingtono valstijų dalyse, 500–2135 m aukštyje, kalnų slėniuose ir žemutiniuose šlaituose.
Laja siaura, kūgiška. Jaunų medžių žievė plona, tiesi, vėliau, suskeldėja, sustorėja iki 15 cm (paskirų iki 30 cm), įgauna rausvai rudą atspalvį. Šakos horizontalios, atvirose vietose augančių medžių žemutinės šakos senstant nukrenta. Spygliai blyškiai žali, 2-5 cm ilgio, rudenį ryškiai pagelsta ir nukrenta. Kankorėžiai ovalūs arba kiaušiniški, 2-3 cm ilgio, 1,3-1,6 cm pločio, sudaryti iš 45-55 plaušelių[1].
Tai aukščiausia ir masyviausia maumedžių genties medžių rūšis. Natūralaus augimo areale medžio aukštis iki 30–60 m, kamieno skersmuo siekia iki 150-221 cm. Istoriniai šaltiniai teigia, kad augdavo iki 65 m aukščio, o stambūs medžiai turėjo iki 250 cm skersmens liemenį.
Dabar masyviausias žinomas kaip „Seeley Lake Giant“ prie Seeley ežero netoli Pakstono (Paxton) stovyklos, Lolo valstybiniame miške (Montanos valstija). Jo tūris 83 m³, kamieno skersmuo 221 cm, aukštis 49,4 m. Kitas masyvus žinomas kaip „The Burnt Corral Larch“ augantis netoli Starkey eksperimentinio miško, esančio Oregono valstijoje. Jo tūris 78 m³, kamieno skersmuo 209 cm bei 39,6 m aukštis. Šiuo metu žinomas aukščiausias vakarinis maumedis auga netoli Green Creek Umatilla valstybiniame miške (Oregonas). Jo aukštis 58,5 m ir 138 cm kamieno skersmuo (pagal Van Pelt 2000). Kanados Britų Kolumbijoje augantis netoliese Bridesville yra 52,4 m aukščio bei su 194 cm skersmens kamienu, o jo laja išsišakojusi 11,9 m skersmeniu (pagal S.Bednarski e-paštą 2012.06.15)[2].
Išgyvena daugiau kaip 493 metus (pagal medžio rievių išmatavimą dar ant augančio medžio). Miško plynėje netoli Cranbrook (Britų Kolumbija) buvo suskaičiuotos 920 rievės (pagal Stoltmann 1993). Taip pat gali būti tas pats medžio kelmas, apie kurį buvo pateikti jau kitų asmenų duomenys 2001 metais, pagal kuriuos buvo suskaičiuotos 915 medžio rievių[3].
Mediena tvirta, naudojama statyboms, popieriaus gamybai, kūrenimui. Indėnai kramto cukringus medžio sakus.
Gerai toleruoja žiemos šalčius, o atlaiko net iki −50 °C šaltį. Vakarinis maumedis netoleruoja paunksmių, bet dėl storos žievės atlaiko miško gaisrus, o jo sėklytės be vargo greitai sudygsta nesenose gaisravietėse.
Pirmą kartą Lewis'o ir Clark'o apibūdintas 1806 metais, bet iki pat 1849 metų nebuvo pripažintas kaip atskira rūšis, kol to nepadarė dabartinio mokslinio lotynų kalba šios rūšies pavadinimo autorius Thomas Nuttall, gyvenęs 1786-1859 metais.
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Vakarinis maumedis (lot. Larix occidentalis) – pušūnų spygliuotis medis, priskiriamas pušinių (Pinaceae) šeimos, maumedžių (Larix) genčiai.
Kjempelerk (Larix occidentalis) er et bartre i lerkeslekta av furufamilien (Pinaceae). Det er et svært høyt tre med høythengende, åpen krone og store grener, inntil 80 meter høyt.
Arten blir 60–80 m høy, diameter inntil 150 cm. Grenene står litt oppover, men unge grener henger ofte litt på disse. Barken er oransjebrun eller rødaktig mellombrun, unge skudd med brun eller gulbrun bark, hårløse og nedhengende med knopper. De mellom- eller lysegrønne nålene er 2-5 cm lange og trekantede i snitt. De tette bladsamlingene avløses ytterst på skuddene av kortere, mer enkeltstående blader, akkurat som hos amerikalerk. Om høsten blir bladene gule og felles. Konglene inntil 4 cm lange, og slankt oppstående, mørkebrune med 40–80 åpne og nedbrettede skjell. Modnes til en rødaktig, siden mørkt rødbrun kongle på fire til seks måneder. Minner om en mindre utgave av sikkimlerkens kongler. Gamle, gråbrune kongler henger i flere år på treet.
Frøene er viktige om vinteren for mange fuglearter. Trevirket er populært for båtbygging, og treet gir også en slags terpentin. Trevirket er også populært på leirbålet i Nord-Amerika.
Arten vokser på 500–2400 meters høyde og tåler −50 °C. Utbredelsen er i det vestlige Nord-Amerika – med Britisk Columbia, Alberta, Idaho, Montana, Washington og Oregon. Det ble innført til Storbritannia i 1881, men når aldri stor høyde i parkene i Europa.
Kjempelerk (Larix occidentalis) er et bartre i lerkeslekta av furufamilien (Pinaceae). Det er et svært høyt tre med høythengende, åpen krone og store grener, inntil 80 meter høyt.
Arten blir 60–80 m høy, diameter inntil 150 cm. Grenene står litt oppover, men unge grener henger ofte litt på disse. Barken er oransjebrun eller rødaktig mellombrun, unge skudd med brun eller gulbrun bark, hårløse og nedhengende med knopper. De mellom- eller lysegrønne nålene er 2-5 cm lange og trekantede i snitt. De tette bladsamlingene avløses ytterst på skuddene av kortere, mer enkeltstående blader, akkurat som hos amerikalerk. Om høsten blir bladene gule og felles. Konglene inntil 4 cm lange, og slankt oppstående, mørkebrune med 40–80 åpne og nedbrettede skjell. Modnes til en rødaktig, siden mørkt rødbrun kongle på fire til seks måneder. Minner om en mindre utgave av sikkimlerkens kongler. Gamle, gråbrune kongler henger i flere år på treet.
Frøene er viktige om vinteren for mange fuglearter. Trevirket er populært for båtbygging, og treet gir også en slags terpentin. Trevirket er også populært på leirbålet i Nord-Amerika.
Arten vokser på 500–2400 meters høyde og tåler −50 °C. Utbredelsen er i det vestlige Nord-Amerika – med Britisk Columbia, Alberta, Idaho, Montana, Washington og Oregon. Det ble innført til Storbritannia i 1881, men når aldri stor høyde i parkene i Europa.
Modrzew zachodni (Larix occidentalis Nutt.) – gatunek drzewa iglastego należący do rodziny sosnowatych. Występuje w Ameryce Północnej, na zachodzie Kanady i północnym zachodzie Stanów Zjednoczonych[2].
Stożkowy, wąski. Dorasta do 50 m wysokości[4]. Jest największym gatunkiem modrzewia. Rośnie bardzo szybko.
Kora czerwonobrązowa, u dojrzałych osobników gruba i spękana.
Igły, długości do 4 cm, jasnozielone i miękkie w dotyku. Na długopędach wyrastają pojedynczo, zaś na krótkopędach – w gęstym skupieniu. Jesienią żółkną i opadają[5].
Męskie żółte, żeńskie czerwone, wyrastają wczesną wiosną. Gatunek jednopienny[5].
Owalna, stercząca, o długości 2 cm, złożona z cienkich łusek nasiennych, spomiędzy których wystają brązowe, wąskie łuski wspierające.
Występuje w Górach Skalistych oraz Kaskadowych, poniżej 2000 m n.p.m., szczególnie w rejonie jeziora Flat Head na północy stanu Montana, gdzie znajdują się największe znane osobniki.
Często tworzy jednogatunkowe lasy. Masowo kolonizuje pogorzeliska leśne[5].
Drewno przeznaczane jest zwykle na opał lub słupy, ale nadaje się również do prac wykończeniowych[4].
Modrzew zachodni (Larix occidentalis Nutt.) – gatunek drzewa iglastego należący do rodziny sosnowatych. Występuje w Ameryce Północnej, na zachodzie Kanady i północnym zachodzie Stanów Zjednoczonych.
Країни поширення: Канада (Британська Колумбія); США (Айдахо, Монтана, Орегон, Вашингтон). Модрина західна росте в горах, на висоті від 600 м і 2100 м над рівнем моря, як правило, на сіро-коричневих, добре осушених підзолистих гірських ґрунтах, помірної кислоти. Клімат холодний, з прохолодним літом і вологою зимою, річна кількість опадів коливається від 450 мм до 875 мм, більша частина їх — це сніг. Може зустрічатися в чистих насадженнях; на початковій стадії після порушення (наприклад, пожежа) панівним може бути Pinus contorta var. latifolia, і Pinus ponderosa в певних областях; пізніше Pinus monticola, Pseudotsuga menziesii, Abies grandis і Abies lasiocarpa, нарешті Thuja plicata і Tsuga heterophylla займають їх місце.
Дерева до 50 м заввишки; довгий чистий стовбур сягає 200 см в діаметрі на рівні грудей; крона коротка, конічна. Кора тонка і лущиться молодою, у дорослих дерев стає товстою (до 15 см), глибоко борозенчастою, червонувато-коричневою. Гілки горизонтальні, іноді опущені в нижній частині крони. Бруньки темно-коричневі. Голки довжиною 2-5 см шириною 0,65-0,80 мм, товщиною 0,4-0,6 мм, м'які, блідо-зелені, стаючи яскраво-жовтими восени. Насіннєві шишки овальні, коли закриті, яйцевидні, коли відкриті, розміром 2-3 × 1,3-1,6 см, на вигнутих стебельцях. Пилок 71-84 мкм діаметром. Насіння червонувато-коричневе, корпус 3 мм, крило 6 мм. 2n = 24.
Найвище відоме дерево роду Модрина належить виду Larix occidentalis, воно росте близько Грін-Крік в англ. Umatilla National Forest, штат Орегон. Висота 58,5 м діаметр на рівні грудей 138 см (Van Pelt 2000). Вік дерева 920 років, повідомлявся по числу кілець від пня в суцільних рубках поблизу Кранбрук, Британська Колумбія (Stoltmann 1993).
Західна модрина є важливим джерелом деревини. Вона може вирости до величезних розмірів з прямим стовбуром і швидко росте у висоту, хоча збільшення в обхваті займає більше часу. Деревина міцна, тверда і сильна і використовується для довгих жердин, залізничних шпал, шахтної деревини, тонкої фанери, та як балансова деревина для паперової промисловості. Смола з деревини має корисні водорозчинні властивості й використовується для різних промислових продуктів, особливо застосовуваних для чорнильного, фарбового і офсетного друку. Використання цього виду в озелененні обмежене, хоча насадження мають добре рости в холодному кліматі. Насіння важливою їжею для деяких птахів, зокрема Carduelis pinus, Acanthis, Loxia leucoptera.
Ніякі конкретні загрози не були визначені для цього виду. Цей вид присутній в кількох охоронних територіях.
Larix occidentalis là một loài thực vật hạt trần trong họ Thông. Loài này được Nutt. miêu tả khoa học đầu tiên năm 1846.[1]
Larix occidentalis là một loài thực vật hạt trần trong họ Thông. Loài này được Nutt. miêu tả khoa học đầu tiên năm 1846.
Larix occidentalis Nutt.
Охранный статусЛиственница западная (лат. Larix occidentalis) — вид хвойных деревьев из рода Лиственница (Larix) семейства Сосновые (Pinaceae).
В Западную Европу введена в 1881 году, изредка культивируется как декоративное растение. В Россию интродуцирована во второй половине XIX века, в культуре редка.
В природе ареал вида охватывает горы Канады (Британская Колумбия) и США (штаты Айдахо, Монтана, Орегон и Вашингтон)[1].
Произрастает в лесном поясе на высоте 600—2100 (до 2300) м над уровнем моря, главным образом по теневым склонам и долинам рек. Лучшего развития достигает на хорошо дренированных богатых, мощных и влажных почвах; очень чувствительна к недостаточному увлажнению почв. Большей частью встречается смешанных насаждениях с псевдотсугой Мензиса (Pseudotsuga menziesii), сосной горной веймутовой (Pinus monticola), сосной скрученной широкохвойной (Pinus contorta), елью Энгельмана (Picea engelmannii), пихтой великой (Abies grandis), пихтой субальпийской (Abies lasiocarpa) и другими хвойными породами.
В молодости растёт быстро, к 40 годам иногда достигает 23 м выс, в возрасте 250—300 лет нередко имеет высоту в 28—30 м. Живёт до 300—500, иногда 600—700 лет.
Дерево высотой 30—50 (до 80) м (самая высокорослая из лиственниц в Северной Америке) и диаметром ствола 90—120 (до 240) см, с короткими ветвями и узко-пирамидальной кроной. Молодые побеги оранжево-коричневые, вначале редко опушённые, затем голые. Кора на молодых стволах чешуйчатая, серо-коричневая, толщиной 8—15 см.
Почки коричневые, голые. Хвоя бледно-зелёная, туповатая, длиной 20—40 мм, на укороченных побегах в пучке по 14—40 штутк. В Санкт-Петербурге хвоя появляется в начале мая, как у лиственницы европейской (Larix decidua), и, желтея, опадает во второй половине октября, несколько позднее лиственницы сибирской (Larix sibirica).
Женские колоски продолговато-овальные, пурпурные или зелёные, впервые появляются у деревьев на 20—25-м году жизни, полная возмужалость наступает в 40—50 лет.
Шишки яйцевидно-продолговатые, длиной 25—35 (до 50) мм, шириной 18—25 мм, состоят из 7—12 рядов семенных чешуек, широко расходящихся при созревании. Семенные чешуйки округлые или усечённые, часто отогнутые назад; кроющие чешуйки с длинными ланцетными вершинками, значительно выставляющимися над семенными чешуйками. Семена беловатые, длиной около 6 мм, с бледным крылом длиной 12 мм.
В 1 кг содержится 225—340 тысяч семян; вес 1000 семян около 4 г. По созревании шишек семена рассеваются при благоприятной погоде в течение двух недель.
Вид Лиственница западная входит в род Лиственница (Larix) семейства Сосновые (Pinaceae) порядка Сосновые (Pinales)[1].
Лиственница западная (лат. Larix occidentalis) — вид хвойных деревьев из рода Лиственница (Larix) семейства Сосновые (Pinaceae).
В Западную Европу введена в 1881 году, изредка культивируется как декоративное растение. В Россию интродуцирована во второй половине XIX века, в культуре редка.