62 FOREST TREES OF THE PACIFIC SLOPE. 



Knobcone Pine. 



Pinus attenuata Lemmon. 



DISTINGUISHING CHARACTERISTICS. 



The form and size of knobcone pine varies considerably, according as it grows 

 in exposed or in sheltered situations. It is commonly from 15 to 30 feet high 

 and from 6 to 12 inches in diameter. Exceptionally large trees are from 60 to 

 80 feet high and from 18 to 20 inches in diameter. Except in very dense stands, 

 trees of these sizes have broad, pyramidal crowns, the slender branches curving 

 outward and upward toward the stem ; the branches grow from the trunk in 

 distant circles, giving an open aspect to the crown. Old trees are peculiar in 

 having the trunk forked near its middle, thus forming a thin-foliaged, open, 

 narrow crown. The bark of old trunks is thin, dull brown, and shallowly fur- 

 rowed and ridged, mainly near the ground ; the ridges have large, loose scales. 

 The bark of young trunks and of branches and upper stems of old trees is 

 smooth and light brown. The foliage is nearly always light yellow-green. The 

 leaves (fig. 22), 3 in a bundle, are slender, often with a twist, and from 3 to 

 sometimes 7 inches long, but mainly from 3? to 5 inches. Leaves persist for 

 about four or five years. The cones (figs. 22, 23) mature by September of the sec- 

 ond season. Clusters of them, rigidly attached and bent down, encircle the main 

 stems of even small trees (from 5 to 8 feet high) and are the most striking 

 character of this pine. They adhere to the branches and trunk indefinitely ; 

 many trees showing that they have retained their cones for nearly fifty years 

 (embedded in the trunk). Moreover, the cones very rarely open until the tree 

 is killed or they are cut from it; then they open only slowly. In collecting the 

 seed it is necessary to force the cones open by moderate artificial heat. When 

 ripe they are a light yellow or clay brown. The seed (fig. 23, b) is blackish. 

 Seed leaves, 5 to 7, sometimes 8. 



Wood rather light and soft, coarse-grained, brittle, pale yellowish brown, and 

 usually with a thick layer of sapwood. 



Longevity. — But little is known of the age limits of this tree. It is com- 

 monly killed by the recurring fires which run over the dl-y slopes it inhabits. 

 Considering the unfavorable conditions (barren and dry soils) under which it 

 grows, its diameter growth, as well as its height growth, is rather rapid during 

 early life (from 15 to 25 years old). Trees from 10 to 12 inches in diameter 

 are from 40 to 60 years old. Probably it does not attain an age of over 100 or 

 150 years. Further study of its longevity is needed. 



BANGE. 



Throughout Coast Mountains of southern Oregon, of California, and also in southern 

 Cascades of Oregon and northern California Sierras. 



Oregon. — Southwestern part south of McKenzie River, and eastward to western slopes 

 of Cascades, where it occurs at 1,000 to 2,000 feet elevation. 



California. — Klamath National Forest, at about 5,000 feet; Trinity National Forest, 

 above 5,000 feet, extending eastward to Shasta and Whiskeytown (near Redding) and 

 southward throughout the coast ranges. Siskiyou County: East slope of Scott Mountain, 

 between Gazelle and Scott Valley, at about 4,000 feet, and thence to near summit ; 

 west slope of Marble Mountain Divide (west of Scott Valley), and thence into Russian 

 Creek basin, scarce on North Fork of Salmon River, especially west of Sawyers Bar ; 

 extreme western Siskiyou County (between Salmon and Trinity summits, on trail from 

 forks of Salmon River to Hoopa) up to about 5,400 feet. Humboldt County: West slope 

 c.f Trinity Mountain (east of Hoopa Valley) between 3,700 and 4,100 feet. In Trinity 

 County on Canyon Creek near Dedrick. Shasta County: Common on Sacramento River 

 about Redding (westward also 10 or 12 miles, reaching Clear Creek), and sparingly 

 up river to Gregory (Baird Switch) ; also along lower McCloud River near Baird, north- 



