More info for the terms:
fire frequency,
fire intensity,
fire regime,
fire suppression,
frequency,
lignotuber,
litter,
natural,
seed,
shrub,
shrubsFire Ecology: Historical documents show that prior to fire suppression,
southern California chaparral usually burned in summer. Fires typically
crept down slopes by means of falling brands and coals, and only
occasionally formed the hot runs on steep slopes that are typical of
today's fires. Large fuels often smoldered for months. This fire
behavior resulted in a mosaic of numerous small burns throughout the
landscape. This landscape pattern is still evident in northern Baja
California, where fire suppression is not practiced. In contrast, most
contemporary southern California fires occur in fall during Santa Ana
Winds, and consume large patches of chaparral. There is a sharp
increase in the size of individual burns north of the international
border. Fire suppression has reduced the number of fires, but because
of the increase in burn size, total acreage burned is approximately the
same on either side of the border [
35].
Southern California chaparral fires typically crown out, burning all or
most of the aboveground portions of shrubs [
1]. Natural fire frequency
varies from a few years to as long as 60, although shrubs cannot survive
many short-interval fires [
35]. Chaparral stands become extremely
flammable within 30 to 60 postfire years, depending upon stand
productivity, climate, and topography [
44]. Laurel sumac has several
botanical features which encourage fire. Aromatic compounds in the
leaves increase fire intensity [
20]. Elapsed time before ignition of
partially dry laurel sumac foliage was 1.80 seconds at 1,382 degrees
Fahrenheit (750 deg C) under laboratory conditions [
36]. The high
surface-to-volume ratio of leaves (126 cm sq/cu cm) transfers heat to
the plant's interior branches following ignition, resulting in more
rapid combustion of the shrub [
46]. Also, mature laurel sumac stands
have deep litter layers. A study of litter accumulation in chaparral in
southern California and northern Baja California showed that laurel
sumac produced the deepest litter of the seven chaparral species
measured [
58].
Plant Adaptations: Laurel sumac's adaptations to fire include the
ability to sprout from the lignotuber after aboveground portions are
burned and postfire seed germination [
11,
60,
61,
62,
63]. Like most
chaparral shrubs, laurel sumac stores photosynthate reserves in the
extensive roots. These reserves are metabolized during postfire
sprouting. Laurel sumac also stores photosynthate reserves in its large
lignotuber. This extra store of reserves probably gives laurel sumac a
postfire competitive edge over many chaparral species [
11].
The seedcoats of laurel sumac seeds in the seedbank are cracked by fire,
resulting in postfire seedling recruitment [
62,
62].
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".
