346 



FOEEST TEEES OF THE PACIFIC SLOPE. 



OCCURRENCE. 



Alluvial bottoms and prairies, moist valleys, dry mountain slopes, benches, borders of 

 streams, water holes, and mountain meadows in variety of soils from rich to poor ; 

 largest in fresh rich soil (lower Columbia River region) and shrubby in dry, gravelly, 

 poor ones (mountain slopes). Forms small groups and extensive pure thickets, inter- 

 spersed with aspen, western choke-cherry, bitter cherry, Oregon crab, and ceanothus, 

 manzanita, and other chaparral brush. 



Fig. 162.- — Amelanchier ahiifolia. 



Climatic Conditions. — Similar to those of western chinquapin ; mild, long, warm 

 growing season appears to determine range of largest growth. 



Tolerance. — Endures considerable dense shade when young, but needs abundant over- 

 head light for best growth. 



Reproduction. — Abundant seeder nearly every year. Seedlings often numerous in 

 moist, humous soil in partial shade ; much scattered and infrequent on dry slopes. 



