to the 90th year, thereafter growing more slowly but persistently until 

 200 to 300 years old. 34 trees in the Lake Slocan region (B.C.) grew 10 

 inches in 68 years and 20 inches in 140 years. In northern Idaho it 

 grows to 12 inches in 100 years. 



Root System. Fairly deep heart root. 



Bole. Cylindrical. 



Crown. In dense stand the crown is conical with short widely 

 spaced branches. In poorer and more open situations the tree is shorter 

 and more spreading. 



Tolerance. Intolerant of heavy shade throughout its life. It is, 

 however, more tolerant than the western larch, Douglas fir, etc., and less 

 tolerant than western hemlock, Engelmann spruce, etc., It is more 

 tolerant m its earlier stages than in later life. Prunes well. 



Wood. Similar to white pine; 24 pounds. 



Reproduction. Seed years every 4 to 6 years, but some each 

 year after the age of 40 to 60 years; not prolific. Cones mature at end 

 of second summer, about September first, and shed seed soon after. 

 Seed winged, light, fair sized. Germination medium, 50 to 70%. 

 Germinates poorly on heavy humus. Prefers fresh mineral soil. Seed- 

 lings require broken shade during first year. 



Range. It is distributed through the forests of the northwestern 

 mountains from the west slopes of the Continental Divide in southern 

 British Columbia and northern Montana to Vancouver Island and 

 through the mountain ranges of Washington, Oregon and California. 

 It is most abundant and attains the best development in northern Idaho. 

 Altitude, sea-level in southern B.C. to 11,000 feet in southern 

 California. 



Climate. Wide range. Temperature extremes -30 and 100 

 Fahr. Annual precipitation varying from 60 inches to a minimum of 

 15 inches. In the northern Rockies and mountains of California the 

 snowfall is heavy and remains on the ground well into the summer. In 

 the southern part .of its range it is subject to long periods of summer 

 drought. 



Soil. Adapted to a variety of soils. Best growth on deep porous 

 soils but most common on poor sandy soils. 



Association. It rarely forms pure stands but occurs as single 

 individuals or in small groups. In northern Idaho it often forms half of the 

 stand, with larch, giant cedar, Douglas, lowland and alpine firs, cotton- 

 wood and white birch as secondary. In general its chief associations 

 are western hemlock, Douglas and white firs, and larch. 



General. Although not forming pure stands, nor reaching as large 

 sizes as many other western conifers, it is an important tree nevertheless 

 because it produces wood of excellent quality, and also grows with other 



