30 BOTANICAL GAZETTE [JANUARY 
three species started growth at practically the same time, and the 
immediate cause was a windfall. The birches are tall and spindling, 
but now slightly overtop the balsams in spite of a somewhat later 
start. Having gained the advantage as to light supply, their 
tops will spread fast, and these trees, or more likely one or two of 
them, will doubtless finally develop the thick-stemmed, spreading, 
round-topped form characteristic of mature specimens in the virgin 
forest. The balsams which are within the sphere of influence of 
the birches will be suppressed. This process in fact has already 
begun. The last 5-10 rings of 
those balsams which were close 
to the birches were found to 
be noticeably narrower than 
the earlier ones, while the 
rings of those growing isolated 
from other trees were uni- 
formly spaced. Undergrowth 
was practically lacking, the 
shade being everywhere very 
dense. Even the ground hem- 
lock was entirely absent. 
S$ balsam z ‘ 
sul alba Ppapyrifere g In this quadrat the moun- 
as ne . ae tain ash showed an interesting 
a2 eke, pa ce habit of growth. Several sap- 
lings were seen among the clos- 
est groups of balsams which were so slender and weak as to closely 
resemble lianes. One specimen was 4.3 m. high and 2.25 cm. 
thick at the base, unbranched, with a single tuft of leaves at the 
top. It was supported entirely by the balsams against which it 
leaned, and its upper portion had penetrated among the interlacing 
balsam branches close to the trunk of a near-by tree. It was 16 
years old, and had evidently started before the balsams had begun 
to shade the ground thoroughly, but was left behind in the severe 
competition for the available light supply. 
QuapRAT 4 (figs. 9, 10).—This quadrat, also of one unit area, 
includes two generations of balsam and no other species. Several 
large birches were near by and a large spruce. The older generation 
