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From: warilaj
To: vzelazny
Subject: soil organic matter
Date: Monday, September 19, 1994 3:48PM
Dear Vince,
Within the last year I have been delving into the topics of
the cumulative effects of forestry practices on soils,
organic matter, soil biota, and potential effects on
fertility.
There seems to be some evidence that soil organic matter
should change and/or be reduced under continuous
silviculture. For example, litter and humus layers may
change in form and composition, or be incorporated into
mineral horizons at an accelerated rate, i.e, mor
humus-forms may be grade into mull forms.
Likewise, it seems logical that changes in soil organic
matter should lead to changes in soil biota, although I
don't know that anyone has a handle on it over the long
term. Possible trends might include bacteria assuming more
significant roles in surface horizons relative to fungi than
they have historically in forest soils.
The jury is still out on the effects changes such as these
might hold for soil productivity. From my reading, evidence
available to date does not indicate that sustained forestry
practice per se is leading to imminent productivity declines
on sites of moderate to good fertility, although effects
may show themselves sooner on poor or harsh sites. This
does not imply that it has been demonstrated that eventual
productivity decline is not possible, but that neither
silvicultural practice nor research have been carried out
long enough to form firm conclusions.
Anyway, I have included below several citations for sources
I found informative.
Best wishes
Jim Warila
Faculty Research Assistant
College of Forestry
Oregon State University
warilaj@ccmail.orst.edu
Sachs D. & P. Sollins. 1986. Potential effects of management
practices on nitrogen nutrition and long-term productivity
of western hemlock stands. Forest Ecology and Management.
17:25-36
Shaw, C.H., H. Lundkvist, A. Moldenke, & J.R. Boyle. 1991.
The relationships of soil fauna to long-term productivity in
temperate and boreal ecosystems: processes and prospects. pp
39-77 IN: Dyck, W.J. and C.A. Mees, (eds) Long-term Field
Trials to Assess Environmental Impacts of Harvesting:
Proceedings IEA/BE T6/A6 Worlshop. FRI Bulletin No. 161.
Forest Research Institute, Rotorua, New Zealand.
Powers, R.F. (et al.) 1990. Sustaining site productivity in
North American Forests: Problems and Prospects. IN: Gessel,
S.P. (et al.) (eds), Sustained Productivity of Forest Soils:
Proceedings of the 7th N. Am. For. Soils Conf. Univ. British
Columbia, Faculty of Forestry, Vancouver, B.C.
(the whole symposium is relevant)
Perry, D.A. and S.L. Rose. 1983. Soil biology and forest
productivity: opportunities and constraints. pp 157-166. IN:
Proc., IUFRO Productivity Symposium. Gen. Tech. Rep.
PNW-163. Pac. Northw. For. Range Exp. St. Portland, OR.
PNW-163
Hendrickson, O., J.B. Robinson & L. Chatatpaul. 1982. The
Microbiology of Forest Soils: A Literature Review.
Information Report PI-X-19. technical Information and
Distribution Centre, Petawawa National Forestry Institute,
Chalk River, Ontario, Canada
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