Forest Development in the Adirondacks 29 
medium (occasional small specimens), LHabenaria obtusata, 
Aralia nudicaulis, patches of a tall growing Polytrichum and 
mats of the liverwort Bazzania trilobata, Abundant seedlings 
of balsam, red maple and arbor vitae and even yellow birch 
are becoming established in the moist sphagnum carpet cover- 
ing buried logs and stumps, so that in this type more than in 
any of the preceding associations one is able to find evidences 
of the actual current progress of the new association which 
is replacing the old. Single erect shoots of the bog shrubs 
Ledum groenlandicum, Kalmia angustifolia and Viburnum 
cassinoides serve to emphasize the contrast between conditions 
in this habitat and the bog shrub associations where these 
species play an important role. In their occurrence and 
changed growth form here one is easily led to regard them as 
survivors of a former vegetation which occupied this same 
ground which indeed they are, as representatives if not as 
individual survivors, if we are correct in regarding this old 
forest as the end of a sequence of bog development. 
When it is recalled that this transition stage from black 
spruce-tamarack bog forest to a semi-balsam swamp type occurs 
on the same physiographic unit hitherto considered —the peat 
covered sand plain—the conclusion seems warranted that the 
foresters’ balsam swamp type of forest may in some cases be 
the temporary climax of a bog sequence of associations. It 
will require further investigation of other areas to determine 
how generally this is the case in the Adirondacks. 
REVIEW OF VEGETATION DEVELOPMENT ON THE GRASSE 
RIVER PEAT BEDS 
In review it appears that the present vegetation cover on 
the peat beds falls into a series of well defined types or associa- 
tions, as follows: 1. The sphagnum-sedge meadow. 2. The 
sphagnum-heath shrub association. 3. The black spruce- 
tamarack association. 4. The pioneer stage of balsam swamp 
forest. There are all stages of intergradation between these 
types representing the invasion of the sphagnum-sedge meadow 
by dwarf heath shrubs tending to form colonies and showing 
