68 Canadian Record of Science. 



remarkable of these is the white cedar, which in the central 

 part of its trend reaches James Bay, but drops suddenly to 

 the south at the Grulf of St. Lawrence in the east, and on 

 reaching the longitude of the head of Lake Superior in the 

 west. Yet the climate and other conditions appear to be 

 the same for some distance both east and west of these 

 lateral boundaries. An outlying colony of the white cedar 

 is found at Cedar Lake near the north-western part of Lake 

 Winnipeg. Colonies or outlying patches of other trees have 

 been noted in different localities, such as of the basswood 

 and sugar-maple at Lake St. John, north of Quebec, of the 

 grey elm on Missinaibi Biver, near James Bay, and of the 

 hemlock spruce at Thompson, near the west end of Lake 

 Superior. 



Bivers and lakes, by supplying heat and moisture and 

 warding off summer frosts, often promote the growth 

 of trees on their immediate banks which are not found 

 elsewhere in the surrounding country. Instances of this 

 may be seen along the North Saskatchewan, where the 

 negundo, green ash, grey elm, white birch, alder, etc., thrive 

 only on the river banks. In the cold regions, the white 

 spruce grows to a much larger size on the shores and islands 

 of rivers flowing north than elsewhere. It has been found 

 that exotic fruit trees and other introduced plants can be 

 successfully cultivated around the shores of the larger lakes, 

 especially on their southern sides, which will not grow at a 

 short distance inland. On the other hand, the immediate 

 proximity of the sea, with a lower summer temperature 

 than the land, is unfavourable to the growth of timber in 

 the north. The habits of some trees are much modified in 

 different latitudes. Species which grow in warm dry soil 

 in the north may be found in cold, heavy, or wet land in 

 the soutb. The larch, balsam, white cedar, white pine, 

 white birch, etc., are examples of this tendencj". Some 

 species extend far to the south of their general home along 

 mountain ridges, while others seem to refuse to follow such 

 lines. The existence of extensive swamps, the shelter of 

 hills, or the elevations which they afford, are therefore to 

 be regarded as among the minor conditions governing the 

 distribution of trees. 



