ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

CONCLUSIONS
The quantity and distribution of ectomycorrhizal activity in forest soils are
governed by a variety of environmental and stand variables. Most important among
these are stand productivity, stand density, accumulation of various types of soil
organic matter (as determined by fire and harvesting history), season and gross
climatic characteristics of the site as reflected in soil temperature and moisture.
We probably can predict the effects of these variables and their interactions in
control 1 ing ectomycorrhi zae.
The immediate impacts of broadcast burning on ectomycorrhizae proved to be
negative; however, the fertilizing effect of a burn may compensate for this initial
loss. Intensive fiber removal had no immediate detrimental effect on ectomycorrhizae,
but on sites with low organic reserves it probably would have negative effects
over long periods of time.
The direct effect of tree harvesting on ectomycorrhizae is a function of host
density. This symbiotic association is usually obligatory for both conifer and
fungus. Residual root systems from cut trees can support only a much reduced
level of ectomycorrhizae for a short time.
Adequate colonization of root systems by ectomycorrhizal fungi is prerequisite
to the growth of conifers in relatively infertile forest soils. Preventing harvest-
re1 ated excess 1 osses in organic material s which support ectomycorrhizal associations
will prevent man-caused site deterioration. On the other hand, natural catastrophies
can also remove or disturb organic soil components over large areas. We feel
natural catastrophies have reduced capacity to support ectomycorrhizae oh many
sites now managed for timber production. Harvest, residues and fuel management
procedures for these sites can be designed to improve organic matter quantity,
type, and distribution, thus potentially increasing timber growth beyond the
capabil ity of natural systems.
LITERATURE CITED
Benson, R. E.
Woody material in northern Rocky Mountain forests : volume, character, and
changes from harvesting. In Proc. Symposium on the environmental consequences
of timber harvesting in ROXY Mountain coniferous forests.
Brown, J. K.
1974. Handbook for inventorying downed woody material. USDA For. Serv. Gen.
Tech. Rep. INT-16, Intermt. For. Range Exp. Sta., Ogden, Utah. 24p.