SPRUCE AND BALSAM FIR TREES. 39 



This author later believed it to be a distinct species, and in 1897 pub- 

 lished the name " Abies shastensis." A long and careful field study 

 of this tree has convinced the writer, however, that it is only a 

 varietal form of Abies magnifica. 



DISTINGUISHING CHARACTERISTICS. 



Abies magnifica is a tree of stately dimensions, ranging from 125 

 to 175 feet in height, or very exceptionally 200 feet or more, and from 

 30 to 50 inches in diameter; trees from 60 to 80 inches in diameter 

 are rather rare. Much larger trees are said to have been found, but 

 the writer has never seen them. Abies magnifica shastensis occurs 

 only at high elevations where conditions for growth are much less 

 favorable than within the main vertical range of the species, so that 

 it rarely exceeds 125 feet in height and 3 feet in diameter. In close 

 stands at lower elevations the trunks of large trees are straight and 

 slightly tapering. Smaller trees on high exposed slopes are often 

 conspicuously and permanently bent down the slope at their base, 

 as a result of heavy snows which yearly force the seedlings to the 

 ground. Their later struggle to regain an upright position never 

 wholly rids the trees of this basal bend in the trunk, which remains 

 a mark of early vicissitudes. 



The bark of young Shasta red fir trees is smooth and conspicuously 

 chalky white, as it is also on the upper stem and branches of old 

 trees, while on the lower trunks of older trees it is rough with deep 

 furrows and narrow, rounded ridges. It varies in thickness from 

 2 to 3 inches according to the size of the tree. The main vertical 

 ridges of the bark are irregularly divided by diagonal furrows, 

 which give a peculiar zigzag appearance to the bark. Externally 

 the rough bark of old trunks is a deep purplish-brown and a bright 

 purple-brown within. No other fir tree in this region has bark 

 similar in any particular to this. 



The crown of old forest grown trees is a short, very narrow, round- 

 topped cone, sometimes almost cylindrical. The short branches 

 droop except at the top of the crown, where they trend upward. 

 The crown is noticeably open, due to the fact that the circles or 

 whorls of branches grow from the trunk at rather wide and regular 

 intervals. Only in the densest stands are medium-size trees clear of 

 branches for half or more of their length. In the high, fairly dense 

 Pacific Slope forests many trees bear straggling branches nearly to 

 the ground. At high elevations, too, the brittle tops are often 

 broken off by wind, when the lost member is replaced by the upward 

 growth of one or two side branches, which soon assume the form and 

 place of leaders. Broken and repaired crowns of this type are 

 familiar sights on wind-swept slopes inhabited by this fir. Young 



