90 SILVA OF NORTH AMERICA. conifek^. 



r 



northern part of the state, and southward along the western slopes of the Sierra Nevada to the main 

 fork of the San Joaquin Eiver in latitude 37° 30' north, where it ascends to elevations of seven thousand 



i 



feet above the sea ^ but it is absent from all the arid mountains which rise in the great basin between 

 the Sierra Nevada and the Wahsatch Ranges. In the dry interior region of the continent, where the 

 Douglas Spruce grows only on rocky mountain slopes and benches, usually singly among other trees, and 

 rarely forms an important part of continuous forests except in northern New Mexico and Arizona, it 

 seldom attains a greater height than eighty feet ; northward it is generally found at elevations of from 

 four to six thousand feet above the sea-level ; in Colorado it is scattered from the upper slopes of the 

 foothills at elevations of about six thousand feet up to eleven thousand feet j ^ it is common on the high 

 mountains of northern and central New Mexico,^ and on the San Fra;ncisco Peaks of northern Arizona 

 it forms a large part of the forest between elevations of eight thousand two hundred and nine thousand 

 feet;^ it is abundant on the Guadaloupe Mountains of western Texas, where in size and numbers it is 

 surpassed only by Piniis ponder osa ;'^ and on the mountain ranges of southern New Mexico and Arizona, 

 where it is comparatively rare and usually of small size, it seldom ascends higher than six or seven 

 thousand feet. It is most abundant and of its largest size not far above the level of the sea in southern 

 British Columbia and in the region between the coast of Washington and Oregon and the western 

 foothills of the Cascade Mountains, where enormous trunks crowded close together rise to a great 

 height, forming, either alone or mixed with the Hemlock, vast almost impenetrable forests 5 these are 

 surpassed in productiveness only by the Sequoia forests of California, and appear to reach their maxi- 

 mum development south of the Straits of Puca on the lower northern slopes of the Olympic Mountains, 

 where rains falls more constantly and copiously than on any other part of the United States with the 

 exception of the Alaska coast. On the Cascade Mountains and the California coast ranges the Douglas 

 Spruce is less abundant and rarely more than one hundred and fifty feet in height, but it frequently 

 grows to a large size on the California Sierras, where it seldom ascends higher than five thousand five 



^^ r 



hundred feet above the sea and is most often scattered among other trees, but sometimes forms small 

 groves, especially on the rough boulder-covered slopes of earthquake taluses which occasionally it almost 

 exclusively covers.^ 



The wood of Pseudotsuga mucronata varies greatly in density and quality and in the thickness of 

 the sapwood. It is light red or yellow, with nearly white sapwood, and is marked by conspicuous dark- 

 colored very resinous bands of small summer cells which generally occupy at least half the layers of 



J 



annual growth, and after the tree has been cut become hard and flinty, making the wood difficult to 

 work. Two varieties of wood, red and yellow, the former coarser grained, darker colored, and less 

 valuable than the latter, are distinguished by lumbermen, and appear to be largely due to the age of 

 the tree, the wood of young trees being coarser grained and darker colored than that of old trees. The 



J. 



average specific gravity of the absolutely dry wood of twenty-one specimens cut in different parts of 

 the country was 0.5157, a cubic foot weighing 32.14 pounds. The wood of Pseudotsuga mucronata^ 



■ r 



which furnishes most of the coarse lumber manufactured in southern British Columbia and in western 



r 



Washington and Oregon,® is largely used for all kinds of construction, for fuel, and for railway-ties; 

 it supplies most of the piles used on the Pacific coast of North America, and spars and masts of 

 unequaled strength.*^ The bark is sometimes used in tanning leather.® 



1 Brandegee, BoL Gazette^ iii. 33. - 8 The following unpublished analysis of a specimen of the bark 



■ 2 Rusby, Bull. Torrey Bot. Club, ix. 79. of Pseudotsuga mucronata from Forest Grove, Oregon, has been . 



^ Merriam, North American Fauna^ No. 3, 121. made by Professor Henry Trimble of the Philadelphia College of 



* Havard, Proc. £/. S. Nat. Mus. viii. 503. ~ Coulter, Contrih. Pharmacy: — 

 U. S. Nat. Herb. ii. 555 (Man. PL W. Texas). 



^ Muir, The Mountains of California, 168. Moisture 6.05 per cent. 



^ In commerce the wood of Pseudotsuga mucronata is often called Ash in absolutely dry material . . 1.22 « 



Oregon puie. Tannin in air dry material . . . 15.25 « 



' Laslett, Timber and Timber Trees, ed. 2, 374. Tannin in absolutely dry material . 16.23 « 



