Environment of the Old-Growth Ponderosa Pine Forests
within the pondersosa pine forests must survive in a region of little precipitation
that primarily falls in the winter as snow. As a result,
these old-growth forests occupy drier sites than any other Pacific forest outside
of the western juniper and oak woodlands. Precipitation ranges from 12 to 40
inches per year forming a mosaic of sites ranging from dry to moist. The growing
season is comparatively short, the winters are cold, and even with summer temperature
averages reaching 80-85°F, nighttime temperatures can drop below freezing.
The predominant characteristic of the ponderosa pine soils is that
they are coarsely textured soils. In much of Oregon, these soils are made largely
of pumice ejected from volcanoes such as the ancient Mount Mazama (now the
site of Crater Lake) and Newberry.