THE GYMNOSPERM TREES 261 



single species is the longleaf pine (fig. 182), which, in addition 

 to producing lumber, is the source of naval stores (see p. 385). 

 As its name implies longleaf pine has leaves twelve inches or 

 more in length, borne in clusters of three. It is a fairly large tree, 

 averaging about one hundred feet in height; its wood is hard, 

 strong and uneven grained due to the abrupt transition between 

 spring and summer wood. For the first five years or so of its life, 

 the young longleaf pine makes practically no growth above 

 ground, but sends a long taproot deep into the sandy soils upon 

 which it characteristically grows. Following this, it enters upon a 

 period of rapid growth, and trees twenty five years old average 

 forty five feet in height and six inches in diameter. 



In western United States we again find large areas of 

 forest growth that are made up chiefly of members of the pine 

 genus. The entire Rocky Mountain region, and the southern 

 Pacific coast region, are covered with coniferous forests whose 

 outstanding individual species are pines. In the Southern Rocky 

 Mountain forest region are extensive forests of ponderosa pine, 

 a magnificant tree growing commonly to heights of over one 

 hundred and fifty feet. The leaves are characteristically borne in 

 clusters of three, although clusters of two are often found on the 

 same tree. It is the most widely distributed pine in North 

 America, and its lumber ranks third in importance on our 

 American markets. It is exceedingly resistant to drought, hence 

 comprises almost 90% of the merchantable timber stands in 

 Arizona and New Mexico, although reaching its best develop- 

 ment in the Pacific coast states where growth conditions are more 

 favorable. In the Northern Rocky Mountain region it is found, 

 in lesser abundance, in company with lodgepole pine and 

 Douglas fir. 



Sugar pine, a five needle pine native to California and 

 southern Oregon, is the largest American pine and one of our 

 finest timber trees. It is closely related to our eastern white pine, 

 and its wood has all of the desirable qualities of the latter. Heights 

 of two hundred feet are not uncommon for this tree and diameters 

 up to ten feet have been recorded. Its long pendant cones, up to 

 twenty six inches in length, are recognizable at a considerable 

 distance. The national importance of sugar pine is limited only 



