ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

.4s shown in fig. 5, vegetation was sparse in the study area's uncut mature
forests. W i th the exception of the chips-spread treatment, a1 1 treatments produced
more vegetation than the uncut forest.
In addi tion, ratios between vegetative components varied subs tanti a1 l y . Whereas
forbs accounted for about a third of the biomass in the uncut forest, they predom-
inated on the treated areas. For example, in the burned-treatment area, forbs
accounted for over three-fourths of the biomass. On the other hand, shrubs accounted
for a third of the biomass in the uncut forest but were practically nonexistent on
treated areas. Grasses were practically nonexistent in the uncut forest and the
chips-spread treatment areas, but accounted for over a third of the lesser vegeta-
tion's biomass in areas receiving the scarified and residues-removed treatments.
None of the biomass values on any of the treatment areas were high. Even the
residues-removed treatment, which had the most, had only 580 kg per ha (518 pounds
per acre).
DISCUSSION
When and how we dispose of wood residues following clearcutting in lodgepole
pine forests has a pronounced effect on subsequent regeneration. This holds true
for both survival and initial development of both artificial and natural lodgepole
pine regenera tion. The dj fferent effects of residues treatments are s ti 11 pronounced
even after 5 years, and the general trend during the first 5 years hints that these
differences will continue. How long differences persist can only be speculated at
this time. However, studies wi th western larch (Larix occidental is) under somewhat
similar circumstances showed seedbed treatments a m i ng seed1 i ng and sapling
development for 10 to 15 years (Schmidt 1969; Schmidt and others 1976).
In this study, conventional methods of seedbed preparation in lodgepole pine
forests resul ted in the highest rates of survival and seed1 i ng development. Resul ts
from this study provide additional support for the use of scarification (dozer
piling and burning of slash) and broadcast burning as far as seedling establishment
and development are concerned. This appears to hold true for all three types of
regeneration--planting , spot-seedi ng, and natural .
Neither the residues-removed nor the chips-spread treatment has much to offer
as far as regeneration during the first 5 years is concerned. Planted tree survival
and growth on areas receiving these treatments has been substantially less than on
the two conventional treatments, and trends indicate these differences are becomi ng
greater rather than amel iora ti ng . The same rela tionship holds true for spot-seedi ng
and to a lesser extent for natural regeneration. The natural regeneration picture
for broadcast burning is clouded in our study because of the problems caused by
delayed burning and subsequent loss of first-year seed1 ings. However, other studies
have indicated that natural regenera tion rates are essentially the same on scarified
and broadcas t-burned areas, wi th somewhat fewer seed1 i ngs surviving on burned seed-
beds (A1 exander 1966).