The climax forest of Isle Royale . place, and thus makes possible a new crop. In addition to the statistical study of the trees, careful noteswere taken of the lower vegetation and the physical factors of thehabitat. Less detailed studies of many other localities were alsomade for comparison with the quadrats. The results of the quadrat studies so far as they concern theclimax forest will now be given in detail. The first four describedwere located on Smithwick Island; quadrats 5 and 6 were upon themain Isle Royale. Quadrats on Smithwick Island Quadrat i (fig. 6).—This quadrat exhibits most cl
The climax forest of Isle Royale . place, and thus makes possible a new crop. In addition to the statistical study of the trees, careful noteswere taken of the lower vegetation and the physical factors of thehabitat. Less detailed studies of many other localities were alsomade for comparison with the quadrats. The results of the quadrat studies so far as they concern theclimax forest will now be given in detail. The first four describedwere located on Smithwick Island; quadrats 5 and 6 were upon themain Isle Royale. Quadrats on Smithwick Island Quadrat i (fig. 6).—This quadrat exhibits most clearly therelations which the different tree species hold to each other and tothe physical conditions of the habitat. It includes but one spruce,an aged giant 250 years old, long past maturity, with sparse fohage, I9I3] COOPER—ISLE ROYALE 25 giving practically no shade. Two healthy birches (105 and 107years old), close together, produce considerable shade in theirvicinity. There are several rather old balsams (64-90 years) well. k^ ^/::^:^^^^®^>^>^ Abies balsamea ^ Picea canadensis , x Betula alba papyrif-era O Purus americana U 5 7 Dead stumps 32 Taxus canadensis Fig. 6.—Quadrat i, Smithwick Island: the symbols indicate the species; thenumbers within them the ages of the trees by tens; for example, a tree marked 6 isbetween 61 and 70 years of age. scattered over the quadrat, and usually more or less isolated fromthe smaller growth. The young trees are practically all balsams,the only representatives of other species being two mountain ash 26 BOTANICAL GAZETTE [january (one a clump of three stump sprouts) and a 20-year old birch in thelower right-hand corner. The young growth is not evenly dis-tributed, but shows a tendency toward grouping, which tendencywill be seen in each of the succeeding quadrats. The larger numberof trees of each group are approximately even-aged. For example,the rather scattered group a that surrounds the 5 balsam stumpscontains 13 balsams, 1
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