_ plainly showed recent suppression. 
Bees pe ee eet ee ee Nene i ae ET OE Rae eee a 
1913] COOPER—ISLE ROYALE 31 
is represented by one individual in the lower right-hand corner, well 
isolated from other trees, 115 years old. The younger generation 
illustrates competition between individuals of a single species which 
began life at about the same time. Fig. 9 shows the age of each 
tree, and fig. ro its diameter, which, it may be noted, maintains a 
pretty constant proportion to height. It will be seen from the 
latter that 4 trees (marked by double symbols) have attained a 
much greater size than the others; and if comparison be made with 
fig. g it will be evident that these 4 are not noticeably older than 
A Bs 
A Ls. 
A 
A a = - 
A a cS A a. aN 
AAA A Sn bd as 
dA As 
re - 
Ay 
AA 2 By AN pp. 
Pn ~ wr; 
A as 
A A A A 
Abies balsamea A 28 
10 
Fics. 9, 10.—Fig. 9, ee 4, Smithwick Island: age of trees; for explanation 
of aba see fig. 6; fig. 10, quadrat 4, size of trees; the numbers indicate the 
diameters of the trees in Acchaotae 
their neighbors. The annual rings of these 4 trees were found in 
every case to be wide and evenly spaced, while those of their less 
favored companions were either very narrow from the beginning or 
This illustrates an important 
principle in forest study, namely, that no reliance can be placed 
upon the size of a tree in fixing its age or in determining its place 
where two or more generations are concerned. These 4 individuals 
in some way gained the advantage early in life and caused the 
suppression of their neighbors. Evidence of the severity of the 
shading was shown by the presence among the living balsams of 
20 dead specimens, averaging a meter in height, and in length of 
