GEOGRAPHICAL DISTRIBUTION OF FOREST TREES IN CANADA. 285 



wherever it has been planted, throughout the lake peninsula of Ontario, 

 and down the St. Lawrence nearly to Montreal, and small trees of it 

 are also doing well at Ottawa. The Kentucky coffee-tree has also been 

 found to grow to maturity at Ottawa. The negundo, or Manitoba 

 maple, has not extended its range east of the western part of Lake 

 Superior, and yet it is found to grow as well all the way to Montreal, 

 900 miles to the east of this, as it does in Manitoba. It is also success- 

 fully cultivated at Lac la Biche, far to the north-west of its natural 

 habitat. The black ash proves quite hardy when transported to Moose 

 Factory on James Bay, more than 100 miles northward of its present 

 range, and where it is exposed to the chilling influence of the sea air. 

 There is little doubt that other kinds of trees, if tried, would be found 

 to flourish beyond their present range. This ability of various native 

 trees to grow far from their existing limits is probably not attributable 

 to an improvement in the climate since they attained their present range, 

 for there is no meteorological proof of such improvement, and, on the 

 contrary, there is evidence that the verge of the forest is retreating 

 southward both in North America and Asia. It is more likely due to 

 the cause above suggested, namely, that sufficient time has not yet 

 elapsed to have permitted the fullest possible territorial expansion of all 

 the species. 



When frost alone operates to check the northward extension of a 

 tree, there would appear to be no reason why such a species should not 

 grow as far in that direction as it can ripen its seeds, even once in a 

 number of years. When early frost happened to coincide with good 

 seed years, many seasons might intervene between crops of ripe seeds, 

 and the natural progress of northward extension would be very slow. 

 The red oak, which requires two seasons to ripen its fruit, would suffer 

 a double disadvantage. The writer has noticed that beech, elm, and 

 black ash-trees, when growing in the most northern situations, seldom 

 bear any fruit. 



As a rule, each species is at its best in the central part of the area 

 it occupies, both as to breadth and longitudinal extension. Following 

 .this rule in cases where the northern limits of certain species only come 

 a short distance into Canada, the finest specimens of these will be found 

 to the southward, in the United States. 



SOME FEATURES OF THE TREE-LINES. 



One of the most striking characteristics of the tree-limits, as shown 

 on the accompanying map, is the approximate parallelism of many of 

 them to the general trend of the various sea-coasts, including those of 

 Hudson Bay: There is, therefore, obviously some connection of the one 

 circumstance with the other, and this connection becomes still more 

 apparent when we also take into consideration the lines of former sea- 

 coasts which must have existed when the land was at lower levels. A 

 study of certain tree-lines shows that their present contours are in some 

 way connected with conditions which existed in late geological times, 

 and that any explanation of them must be involved with questions of 



