ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

RESIDUE DECAY PROCESSES AND ASSOCIATED ENVIRONMENTAL
FUNCTIONS IN NORTHERN ROCKY MOUNTAIN FORESTS
M. J. Larsen, Research Mycologist1
Center for Forest Mycology Research
USDA Forest Service, Forest Products Laboratory
A. E. Harvey, Research Plant Pathologist
USDA Forest Service, Intermountain Forest
and Range Experiment Station
M. F. Jurgensen, Professor of Forest Soils
Department of Forestry
Michigan Technological University
ABSTRACT
Decaying and decayed wood has received little attention in its
relationships to the properties and functions of forest soil s,
although it is recognized that decay of woody substrates in
forested ecosystems constitutes a major pathway for carbon and
nutrient recycling.
Results from our investigations indicate that brown-cubical decayed
wood in soil is more functionally unique than previously thought.
Wood in soil exhibits functions and characteristics that qre
similar to those of other soil components, but in some instances
performs more efficiently. Wood in soil is an efficient medium for
storing nutrients and water. It also provides a place for growth
of tree roots and certain fungi that together form "mycorrhizae",..
structures essential to tree establ ishment, survival, and growth in
western forests. Decayed wood is an important site for the bio-
logical fixation of nitrogen gas from the atmosphere. Since soil
wood is an important part of soil structure and function, it is
necessary to determine how much residue (wood) can be removed for
further utilization and product development without precipitating
site deterioration, By assessing the impact of increasing levels
of utilization before forest harvesting and utilization, long term
site deterioration or damage may be avoided.
KEYWORDS: decay, lignin, fungi, bacteria, N2-fixation, soil wood,
mycorrhizae, psychrophiles, nutrient cycling
'~aintained at Madison, Wisconsin in cooperation with the Uni yersi ty of
Wi sconsin.