Forest Development in the Adirondacks 25 
Growth and Vegetative Propagation. The shrubs named pos- 
sess in common the quality of vigorous and rapid vegetative 
multiplication which results as previously mentioned in the 
formation of spreading colonies and accounts, apparently, for 
the spotwise occurrence of them. .These phenomena are dis- 
cussed in a separate paragraph. (Page 40.) 
The Black Spruce — Tamarack Association. Bog Forest 
At the present time there is only a small portion of the west 
section of the Grasse River Marsh which may be said to have 
reached the culmination or bog climax stage of closed high 
forest. Most of the west section and the north end of the 
east section are covered by young conifer stands and while 
most of the northern third of the east section may be character- 
ized as an open stand or even quite scattered occurrence of 
black spruce and tamarack in the invaded shrub zone, viewed 
as successive aspects of vegetation development this transition 
from pure sphagnum-shrub association to the black spruce- 
tamarack association presents exactly the situation previously 
described in tracing the succession from pure sedge meadow 
through various stages of invasion and complete dominance by 
the heath-shrub and associated species. 
(a) Stages in the Invasion of the Sphagnum-Shrub Associa- 
tion by Bog Conifers. The northern third of the main marsh 
area presents for the most part a scattering or fairly open 
stand of black spruce and tamarack among a heavy growth of 
bog shrubs in their characteristic mound forming colonies. 
(Figures 15, 16.) Toward the north boundary the conifers 
form a closed stand of young forest. The explanation here set 
forth is that in this part of the marsh we have a concrete exam- 
ple of the continuing, normal course of vegetation development 
in which species of bog conifers invade the sphagnum-heath 
shrub association and establish a bog conifer forest in its stead 
just as in the preceding step the shrub vegetation had over- 
come and replaced the sphagnuim-sedge stage. From this point 
ef view, the vegetation is regarded as inevitably moving for- 
ward toward a stage of stable equilibrium — seeking its high- 
