24 EDWARD W. BERRY 



black poplar and of our American balsam poplar has often been 

 employed by herbalists for various medicinal purposes although 

 it has little virtue. 



There are in all about twenty-five existing species of poplar, 

 of which half are found in North America. Among these the 

 ones known as aspens have an especially wide range, particularly 

 the quaking aspen, Popuhis tremuloides, which covers 112 de- 

 grees of longitude and 41 degrees of latitude, while the European 

 aspen (Populus iremula) covers 140 degrees of longitude and 

 35 degrees of latitude — the two together nearly encircling the 

 globe. They form dense growths in the north woods and furnish 

 most o'f the drift wood of the Arctic Ocean. Although cut in 

 vast quantities for pulpwood the aspens will probably always 

 form an important element in the more northern forests as they 

 and their ancestors have done during the past three or four 

 million years. They repeat the usual poplar characters of 

 smooth bark, soft weak wood, very rapid growth and sparse 

 broad leafed foliage. They are more gregarious and somewhat 

 smaller at maturity than the other poplars and their long slender 

 leaf stalks cause the lightest summer breeze to set the leaves 

 to quaking or trembling with the characteristic motion and 

 sound that gives them their vernacular names. Other interest- 

 ing poplars are the so-called cottonwoods of the West, where 

 they are almost the only native trees in the river valleys of the 

 prairie country, ranging from Assiniboia to New Mexico. The 

 Cottonwood has narrower leaves than the rest of the poplars 

 v»^hich in the commonest species approaches a willow leaf in 

 appearance. 



Neither willow nor poplar timber can compete with larger and 

 stronger woods such as pine or spruce or with more durable 

 woods such as oak, cedar, and chestnut. Pulpwood, excelsior, 

 and fuel are their largest uses although for barn floors, boxboard 

 veneer, spools, matches, etc., their qualities of softness, light- 

 ness, ease of working and lack of splintering, render them 

 valuable. 



The geological history of the poplars is most interesting, there 

 being about 125 fossil species, in. addition to the still existing 



