The resistance of a leaf to molecular gaseous diffusion
is an important physiological response. Control of
leaf resistance enables a plant to control its transpired
water loss and regulates photosynthesis.
Four study sites representing a gradient in available
moisture and evaporative demand, were chosen in western
Oregon for the study...
Four study sites were selected along an altitudinal gradient on Mt. Ashland in the Siskiyou Mountains of southern Oregon. The altitudinal gradient roughly corresponded to a gradient in temperature and water availability ranging from very hot and dry to cool and moist. Air and soil temperatures were continuously measured on...
Clearcutting is a sound silvicultural practice when exercised
in the proper environmental location. Foresters have learned through
bitter experience that clearcutting Douglas-fir forests, located on
droughty south-facing slopes, often leaves uncorrectable regeneration
problems. Thousands of acres of unproductive grass and brush throughout
the Douglas-fir region are unavoidable reminders of inappropriate...
In a mountainous region of southwestern Oregon where temperature, moisture and nutritional status of forest communities have already been classified, the influence of tight upon conifer growth and plant distribution was investigated. Light, measured in calories cm day' (400-700 nm) during clear summer days was used as an index to...
When trees from 16 populations of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco. var. menziesii) were grown at ten geographically diverse locations for seven years, those from a Vancouver Island source were among the top three for height growth on nine of the ten plantations (Rowe and Ching, 1974). In contrast, growth...