10 



YOSEMITE NATURE NOTES 



intolerant of shade and under crowd- 

 ed conditions it produces a very long, 

 slender trunk with a small rounded 

 crown occupying but the upper third 

 of the tree's height. 



It prefers moist, sandy, mineral 

 soils and thus is most commonly 

 found along streams and canyon bot- 

 toms where it often forms attractive 

 groves. Under such conditions it rar- 

 ely fails to gain the admiration of the 

 passerby for what it lacks in size it 

 overcomes in grace and beauty. 



The aspen is not a large tree, the 

 maximum height being about 50 to 

 60 feet and the diameter 12 to 30 in- 

 ches. It is also short-lived, rarely 

 being more than 50 to 60 years old. 

 Trees 10 to 14 inches in diameter 



average about 30 to 40 years of age. 

 The leaves, almost round in outline 

 and ending in a definite point at the 

 apex, are one and one-half to three 

 inches in diameter, and edged with 

 small, regular serrations or teeth. 

 They are shiny and smooth, deep yel- 

 low-green above and lighter on the 

 underside. The most distinctive char- 

 acter of the leaves, however, is their 

 habit of fluttering in the slightest 

 breeze. The reason for this is readily 

 accounted for by the long leaf stem 

 or petiole (one and one-half to three 

 inches in length) which is flattened 

 from the sides. The specific name, 

 tremuloides, was applied because of 

 the quivering habit of the leaves. It 

 also accounts for the common name 

 of quaking aspen. 



holiagc and floucn of quaking asprn (Inch iquarcs on background) 



