62 Native Trees oj Canada 



as the familiar silver poplar {Popiilus alba), distinguished by a dense, white, 

 persistent down on the under surface of the leaf, and the tall, erect Lombardy 

 poplar {Poptdus nigra var. Italica), have been introduced and are growing all 

 through the older settled portion of Eastern Canada. 



The poplars are related to the willows and resemble them in their habit and 

 in their method of reproduction. Even the leaves of some species resemble those 

 of the willow. They are readily distinguished from these trees, however, by their 

 winter buds. The buds of the poplars have many scales and those of the willows 

 have but one. 



The seed is very minute, light, and tufted and is easily carried long distances 

 by the winds. This, together with its abundance, probably accounts for the wide- 

 spread distribution of the poplars. 



Many of the species propagate by means of suckers that spring from the roots^ 

 and most of them sprout readily from the stump when cut. The artificial repro- 

 duction of these trees is done chiefly by planting cuttings. 



POPULUS TREIVIULOIDES, Michx. ASPEN 



Common names: Aspen, asp, trembling aspen, quaking asp, 



aspen poplar, white poplar, popple, smooth-barked poplar, 



poplar. 

 French names: Tremble, peuplier faux -tremble, peuplier tremble, 



peuplier d'Athenes, bois blanc*, peuplier. 



The aspen is a tree of very wide distribution, extending completely across 

 Canada from Labrador and Hudson bay to the mouth of the Mackenzie river and 

 Alaska. 



It is not a very large tree, averaging about 40 ft. in height and 8 to 10 in. in 

 diameter, but sometimes reaching a height of 90 ft. and a diameter of 24 in. The 

 trunk is slender and the crown round-topped and open. 



The bark is rough w4th flat ridges and deep furrows, becoming paler on limbs. 



The twigs are slender, reddish, and smooth and the winter buds small, shiny, 

 and slightly sticky. 



The leaves are IJ^ to 2}/^ in. long and in outline are almost circular. The apex 

 is pointed and the base often slightly heart-shaped. The margin is finely toothed. 

 The upper surface is dark green and the lower surface slightly paler. The leaf- 

 stem is much flattened sideways making the leaves very unstable and causing 

 them to tremble in the smallest breeze. 



It is a very prolific seeder, shedding seed early in the summer. The seed is 

 very minute and light, and attached to a downy tuft which causes it to be carried 

 long distances by the wind. For this reason it is often the first tree to come in on a 

 burned area. 



It grows best on well-drained loam, but is found on a large variety of soils. 

 It occurs most frequently in pure stands or mixed with other light-seeded species, 

 such as the balsam poplar, large-toothed aspen, or the birches. The growth is 

 rapid but not persistent. It is much subject to certain forms of fungus disease 

 and is not a long-lived tree. 



