The history and role of fire in forest ecosystems of the central western Cascades of Oregon determined by forest stand analysis

A reconstruction of fire history from 1150 AD to the presentwas made based on forest stand analysis in two study areas in the
central western Cascades of Oregon. The study areas are located
immediately north of the H.J. Andrews Experimental Forest within
the Willamette National Forest. The Cook Creek - Quentin Creekstudy area is located in steep, irregular topography and has anaverage elevation of about 820 m. The Deer Creek study area islocated in more gentle upland topography with an average eleva-
tion of 1220 m. The tree ring records available in stumps of
clearcuts and road right-of-ways were used to determine origin
dates of seral tree species and fire scar dates. These data were
used to determine major fire episodes.
The fire regime for both study areas proved to be morecomplex than the initial assumptions of large, infrequent, cata-
strophic fires. A highly variable fire regime was found. Some
sites burned every 15-20 years while other sites burned once
every 400-500 years. The intensity of each fire appears to have
been highly variable as well. In most cases fairly small irregu-lar patches were burned at stand replacement intensity whileother patches burned at moderate to low intensity.
Fire was more frequent in the Cook Creek - Quentin Creek
study area (natural fire rotation 96 years) than in the Deer
Creek study area (natural fire rotation 138 years). On many
sites multi-aged stands were found with several age classes
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resulting from recurrent low to moderate intensity fires. Othersites had even-aged stands dating from the last stand replacement
fire. Patches in the forest mosaic created by different levelsof fire intensity in the 1800-1900 AD period were analyzed.
Small patches (less than 10 hectares) dominated the patch size
distribution. More area was burned by moderate to low intensityfires than by high intensity fires during that period.
The influence of physiography, environmental gradients andman's activities on the fire regime is discussed. Implicationsof this work for current research in these ecosystems in theareas of geomorphology, stand dynamics and wildlife habitat are
also discussed.