Landscape patterns of pre-logging forest conditions in western Oregon
pre-logging forest conditions were quantified for three landscapes in western
Oregon. The spatial coincidence between forest patches and topographic
features was determined for slope gradient, aspect, elevation, and distance
from streams. Pre-logging and current forest compositions were compared.
The pre-logging landscape was dominated by old growth conifer with
less than 10% consisting of early seral disturbance patches. Fire patches
differed in size and shape between the Oregon Coast Range and the Oregon
Cascade Range provinces. The size and variability of fire patches was larger in
the Cascades, with shorter mean distances between fire patches and smaller
perimeter to area ratios compared to fire patches in the Coast Range. Mean
fire return intervals ranged from 170 to 292 years for the Oregon Coast Range.
The most frequent patch size, regardless of patch type and study area, ranged
from 100 to 999 ha. Forest patch types varied predictably by topographic
feature for instance: fewer fire patches occurred on cool, moist aspects while
more occurred on hot, dry, aspects. More burn area and less old growth
conifer than expected occurred within 4000 m of major rivers. Late seral
forest cover has declined dramatically across all three landscapes since 1933.
Advisor:Ripple, William J.; Means, Joseph; Fiorella, Maria; Kreuger, William
School:Oregon State University
School Location:USA - Oregon
Source Type:Master's Thesis
Keywords:landscape assessment oregon old growth forests aerial photography in forestry
Date of Publication:07/30/1996