The subject of this study was the determination of the changes
in photosynthesis, respiration and transpiration in two ecotypes of
Douglas-fir as caused by decreasing soil moisture content. The photosynthetic
rate was also correlated with the relative turgidities of
needles.
All the above processes were greatly affected by decreasing
soil...
The ecological and silvicultural importance of snowbrush,
Ceanothus velutinus, in the areas west of the summit of the Oregon
Cascades was studied. Particular attention has been given its nitrogen-
fixing ability under both field and greenhouse conditions.
On west slopes of the Oregon Cascades snowbrush occurs above
2, 500 feet...