40 BULLETIN 460, U. S. DEPARTMENT OP AGRICULTURE: 



DISTINGUISHING CHAKACTEKISTICS. 



In the Pacific slope region this pine grows in rather open stands 

 and forms a dense rounded or pyramidal crown of large, much- 

 forked branches which often extend down to the ground. In its 

 high mountain range within the Rocky Mountain region it grows in 

 very close stands and develops a tall, clean, slender shaft with a 

 short, rounded, small-branched crown. This characteristic form in 

 its more eastern range has given the tree the name of " lodgepole 

 pine." The thin scaly trunk bark is pale brown with a grayish tinge. 

 In close stands the height is from 50 to 100 feet, the usual diameter 

 being from 12 to 24 inches. Taller and larger trees sometimes occur. 

 The smooth looking trunks are clear of branches for from 30 to 60 

 feet. 



The foliage is a bright yellow-green. The leaves (Pis. XXVI, 

 XXVII) are borne in bundles of 2 and are nearly one-eighth of an 

 inch wide and from about 1 inch to nearly 3 inches long, but usually 

 they are about 2 inches long. Each season's growth of leaves remains 

 on the trees for from 6 to 8 years. Young trees, however, sometimes 

 retain their leaves for 9 years. The edges of the leaves bear minute 

 sharp teeth (serratures). A cross section of the leaves shows one 

 or two resin ducts. 



The cones (Pis. XXVI, XXVII) ripen late in August and Sep- 

 tember of the second season. On many trees, the cones open in late 

 autumn arid shed nearly all of their seeds, while the cones of other 

 trees in th t e same locality may remain closed for a number of years. 

 The cones adhere to the branches for a great many years, some of 

 the closed ones finally opening and liberating their seed. 1 When the 

 cones are fully ripe the tips of their scales are shiny and of a clay- 

 brown color, the inner or unexposed portion being a bright purple- 

 brown. The seeds (PL XXVII, b) are a deep reddish-brown, with 

 black-brown spots. The seed-leaves vary in number from 3 to 6, but 

 usually there are 5 (PL XXVII, a). 



The wood of trees grown in dense stands, as in the Rockies, is ex- 

 tremely narrow-ringed; while that of trees in open forests, as in the 

 Pacific region, is moderately wide-ringed. The thick layer of sap- 

 wood is almost white and the heartwood is of a clear yellow or 

 yellowish-brown color; the heartwood of the Pacific coast form is 

 usually pale brown tinged with red. The wood is rather hard, stiff, 

 and straight-grained. A cubic foot of the dry wood of the Pacific 



1 The wonderful reproductive power of this species on areas over which it has been 

 killed by fire is dependent upon the ability of the closed cones to endure a fire which 

 kills the trees without injuring their seeds. After fire, the cones open, shed their seeds 

 on the bared ground, and a new growth springs up. Another remarkable adaptation in- 

 suring this tree against extinction by fire is its habit of producing fertile cones at the 

 early age of from 7 to 10 years. 



