210 BOTANICAL GAZETTE [MARCH 
One of them was hollow, and all were more or less attacked by rot. 
The black spruces were found to be somewhat younger than the 
tamaracks. All were solid to the heart. The balsams, which were 
most numerous of the tree species, were of various ages from 47 to 
161 years. No young balsams were present and the average age 
was very high (105 years). All 
showed signs of suppression dur- 
ing early life, probably due to 
shading by the faster growing 
bog trees. Within the last half- 
century the tops have reached 
the sunlight, and most of the 
balsams are now growing rapidly, 
though many are rotten hearted, 
as is common with this species. 
Two birches close to the quadrat, 
1.5 dm. and 2.25 dm. in diame- 
ter, were found to be 62 and 69 
years old respectively. No white 
spruce occurred in this locality, 
but the species is present in most 
areas of bog forest. A striking 
fact is the absence of reproduc- 
tion (fig. 46). No tree younger 
than 47 years was seen except 
a few one or two-year-old seed- 
lings of birch and mountain ash, 
Fic. 46.—Bog forest interior; locality : sad 
of quadrat 10: two large tamaracks in the which seem able to germinate 
background; black a balsam, and in deep shade but not to continue 
Alnus incana; ca of Carex trisperma growth. 
with Petasites and pc species; note ‘ pee b- 
absence of tree reproduction. The history of the area 1s pro 
ably as follows. The present 
generation of trees of both bog and climax type started during the 
period of open bog conditions, and growing up together produced 
so dense a shade as to inhibit the starting of new growth beneath 
them. Shelter from wind, due to the depression in which they 
grow, is doubtless the reason for the absence of windfalls and the 
unusually long life of the balsams. No reproduction will take 
