6 1 2 The yo2Lrnal of Foi^esijy. 



11. Popidus trcmuloidcs (Micliaux), Quaking Asp, is a small tree, 

 seldom more than twenty to thirty feet high, and a few inches diameter ; 

 and in the north it becomes a mere shrub. A form of this species in 

 the valleys of the Eocky Mountains springs up spontaneously in the 

 greatest abundance wherever the woodlands have been burned over. 

 The older trees have stems of fifty to sixty feet in height, and are 

 used in construction. This plant is almost unique as a deciduous 

 tree, among the evergreen conifers of that extensive region. Gene- 

 rally speaking this species has little value, but there are some peculiar 

 forms of this and the next that are cultivated for effect in gardens 

 and parks. 



12. Pofmlus grandidcntata (Michaux), the Michigan Poplar of the 

 nurserymen's catalogues, is a much finer tree than the last, and also 

 northern in its habitat. On account of its rapid growth this tree has re- 

 ceived much attention among western tree-planters, and though only 

 a poplar, considerable merit has been accorded to it as a fencing 

 material ;* the poles cut in early summer and tested, have been 

 found to last ten and twelve years when nailed to posts as a fence ; 

 they are, however, like all their kind, deficient in strength and easily 

 broken. 



13. Populus canescens (Michaux), or more correctly P. alha, L., Abele 

 is the common white or grey poplar of Europe, with its many forms 

 or varieties of Abele, Athenian, maple-leaved, and silver poplars. 



Though widely diffused and planted everywhere, and wonderfully 

 midtiplied by numerous suckers in their new homes, these are all 

 believed to be of European origin. If correctly understood, however, 

 my good friend Professor Karl Koch, of Berlin, who has made a life 

 study of trees, considers this species to be American, or common to 

 both hemispheres. His valuable work is just now, unfortunately, not 

 at hand.i* 



In Southern Europe the white poplar becomes a noble tree, attain- 

 ing the height of 90 to 100 feet, and a diameter of 5 to 6 feet, as seen 

 in the Praterat, Vienna, Austria. The timber is much used in the con- 

 struction of buildings and for other purposes in Europe, and the tree 

 may be found valuable to our own western planters. Michaux claims 

 two distinct trees, the white and the grey, attributing superiority to 

 the latter. 



Popidus tremida (Linn.), Trembling Poplar or Aspen, the congener 

 of our P. trcimdoides, is a European tree of small size and of little value, 

 except to cover denuded tracts as a restorer of the soil, preparatory 

 to the introduction of some other more valuable species. J 



* Forest Trees. Arthur Bryant, sen. New York, 1871, p. 124. 



t K. Koch's Dendrologia, Berlin. 



X 5Ian. Forestale, G. C. Sizmoni, p. 86. 



