TBANS ACTIONS OF SECTION F. 873 



and go as high as latitude 50° and 55°, in longitude 80° and 90° west, and to north 

 of 60°, in longitude 120°, in the valley of the Mackenzie River. These forests 

 probably cover two millions of square miles ; and the conifers to the north an 

 additional million. The cone-bearing trees are found in a broad belt west of the 

 Rocky Mountains, sweeping around the shores of the North Pacific and Arctic 

 seas, down the coasts of Hudson Bay and Labrador, and across the lower St. 

 Lawrence, keeping in the cooler and more humid climates of the Pacific, Arctic, 

 and Atlantic oceans. Among these forests are also found white birch and poplar. 



The deciduous trees cover the parts of the continent having high temperatures 

 and more or less copious rains in the summer months. The maple, beech, bass- 

 wood (linden), elm, oak (Quercus alba), ash, and some others, require a summer 

 of from 63° to 65°: and the white wood (Liriodendron tidipifera), buttonwood 

 (Platanus occidsntalis) , pepperidge (JS'yssa midtifora), sassafras (Sassafras officinale), 

 and others, are found only in the south of Canada, where the summers are higher 

 than 65°. 



The conifers are also found among the deciduous forests, and in some places 

 predominate ; but where they are burned down or die, their place is almost exclu- 

 sively taken by deciduous trees. About 1850 a very extensive forest of pines 

 (Pinus Strobus), covering many million acres in the south-west of Ontario, died. 

 When the writer passed through that region in 18G2, not one live pine could be 

 found, but poplars, oaks, and other deciduous trees had sprung up in the dead 

 forest. 



The uniform rainfall during the summer months in Canada and the eastern half 

 of the United States, with summer temperatures varying from 50° to 80°, are 

 conditions favourable to the growth of forest trees. The absence of rain in the 

 western half of the Republic is a sufficient cause for the absence over extensive 

 regions of all vegetation except the cactus and artemesia, or sage of the desert — 

 emblems of an arid region; Much of this part of the continent is, like the 

 desert of Sahara, rainless, treeless, and desolate. 



Between this arid region and that of the regular summer rains to the north and 

 east — the areas of the woodlands — lie the prairies. In these grass zones there is 

 not rain enough for forest trees, but enough to keep alive the wild grasses. The 

 tops of these die during the droughts of summer, but the roots have vitality 

 enough to germinate under the rains of autumn and spring. Trees, however, 

 which may have been killed by droughts have no such vitality. North of the 

 parallel of 49°, east of the Rocky Mountains, there are about 120,000 square miles 

 of prairie land. Between this and the north Saskatchewan, to latitude 53° and 54°, 

 prairies predominate; north of that river two-thirds of the land is covered with 

 forests. Along the eastern base of the Rocky Mountains, and extending up into 

 their recesses, is a belt of conifers, the principal tree being the Douglas pine 

 (this tree is, however, an Abies), and the white and black spruce. East of the 

 mountains the watersheds are mostly covered with heavy forests of spruce, but 

 the dry ground, where there are trees, with poplars (Popidus tremuloides). The 

 balsam poplar (P. balsamifera) grows to an enormous size on the Athabaska 

 (latitude 55° to 58°) and Mackenzie rivers (north of 60°), often from seven to ten 

 feet in diameter, and one hundred feet in height. 



The forests of British Columbia west of the Cascade Mountains are very fine, 

 and here the Douglas pine or spruce (Abies Dout/lasii) and giant cedar attain 

 their greatest dimensions. On the western slopes of the Rocky Mountains are 

 many species of pine and fir, which in the near future can supply the eastern 

 plains with enormous quantities of timber. 



The comparative value of prairie and woodland for agricultural purposes is a 

 question often discussed. The absence of trees is undoubtedly caused by a 

 climatic defect, and that defect is manifestly the deficiency of moisture. The 

 areas of summer droughts in the Old and New Worlds, in Australia and South 

 America, are identical with the treeless regions. This climatic defect must operate 

 permanently and with increasing intensity upon plants where such lands are 

 Drought under culture. A climate destructive to trees could not be propitious to 

 fruit-trees, and certainly not to any of the grains, grasses, asd root- crops. Tern- 



