OS eS ON en ee Se Sa ae age ace Re re lee TY ore feet SR 
1913] COOPER—ISLE ROYALE 37 
discover, the impression has been gained that the same association of 
balsam, paper birch, and white spruce, which is the dominant 
forest type of Isle Royale, is found in the most mesophytic habitats 
throughout northeastern Canada. The probability is that it is 
the climax type over much of the region, though there is not suffi- 
cient evidence to justify a confident statement to that effect. It 
is not necessary that the component species bear the same relations 
to each other in all parts of the region, or even that the species 
themselves be everywhere the same. One or even two of the climax 
trees may be lacking in certain places, species that are ecologically 
equivalent may be substituted, or others added. Analogous differ- 
ences occur in the deciduous forest. The two climax trees that are 
almost omnipresent are the maple and the beech, and yet there is a 
belt along the northern edge of the region where the maple alone 
forms the climax forest, unless the yellow birch (Betula lutea) may 
possibly take the place of the beech. Again, in the Great Lakes 
region a third climax tree, the hemlock (Thuja canadensis) is 
present; and in the southern Appalachians the number of species 
composing the climax forest reaches a dozen or more. Similarly, 
in northeastern Canada the climax forest may vary from place to 
place. 
Of northern Quebec Macoun (39) says: ‘In the country 
around Lake Mistassini it [balsam] grows mixed with aspen, birch, 
and white spruce, and on the lower part of the Rupert River it is 
found growing with the same trees all the way to James Bay.” 
The correspondence of this to the Isle Royale forest is striking. In 
reports of the Department of Lands and Forests of Quebec (45, 46) 
expressions such as the following are frequent, the region described 
being the country north of Lake St. John, west to Lake Abitibi: 
“well timbered, mostly with spruce, fir, and white birch, with some 
scattered white and Banksian pine on the high ridges.” In the 
“Report of the survey and exploration of northern Ontario” (43) 
there is much detailed information concerning the distribution of 
the trees in that region, though the data presented have little 
ecological value. However, in reading the reports of the various 
parties one frequently comes upon such statements as the following: 
“chiefly small poplar [Populus tremuloides|, spruce, white birch, 
