260 TREES OF MINNESOTA. 



full development of the leaves in May or June. A genus of about 

 twenty species of soft wooded trees, mostly natives of cold cli- 

 mates, one-half of which are found in North America. 



Populus tretnuloid.es. Aspen. American Aspen. Quak- 

 ing Asp. Poplar. Popple. 



Leaves ovate or obicular, with a sharp, short apex, small, 

 smooth on both sides; petiole long, flattened. Flowers in April 

 before the leaves in hairy catkins. Fruit a small, two-valved 

 capsule; seeds very small. Bark smooth, greenish white except 

 on very old trees; twigs not angular. This is generally a small, 

 short-lived tree, but occasionally it grows sixty or more feet 

 high. The penduloife leaves tremble in the slightest breeze; the 

 silver gray bark is attractive and the autumn color of the leaves 

 is one of the purest golden yellows found among trees. 



Distribution. From Southern Labrador to southern shores of 

 Hudson Bay, to the Mackenzie and Yukon rivers, south to 

 Pennsylvania, Missouri, New Mexico and Lower California and 

 through all mountain ranges of the West. One of the most 

 widely distributed trees of North America. In Minnesota it is 

 found throughout the state, and is very common on cut-over tim- 

 ber lands, where it is generally the first tree to take possession 

 of the land after the pine is cut off. It grows most luxuriantly 

 along the borders of swamps and open forest glades. The seed 

 is carried long distances by the wind. 



Propagation. By seeds, which grow freely; but the seeds, 

 however, are seldom sown in nurseries, as the limited demand 

 for this species is easily supplied by the seedlings which spring 

 up along the lake shores and sand bars. 



Properties of Wood Light, soft, not strong, close grained, of 

 cottony fiber, and soon decays in contact with the soil. It is of 

 a light brown color, with thick, nearly white, sapwood. Specific 

 gravity, 0.4032; weight of a cubic foot, 25.13 pounds. 



Uses. On account of the color of the bark and the autumn 

 color of the leaves an occasional specimen of Aspen can be used 

 to advantage to give variety to our tree plantings. Although it 

 grows rapidly when young, it is of very slow growth when older. 

 The wood is used for paper pulp, and occasionally for interior 

 finishing and for turnery. It makes good light fuel if cured 

 under cover. 



