Articles of Interest
Effects of Organic Matter Retention and Other Soil Management Practices on Long-term Productivity of a Pacific Northwest Coastal Douglas-fir Site
Robert B. Harrison, Associate Professor of Forest Soils
Robert L. Edmonds, Professor of Soil Microbiology
Amy Sidell, Barry Flaming, Gage Wagoner, Michael Lolley,Graduate Students
College of Forest Resources, University of Washington
Thomas A. Terry, William Scott & Ron Heninger, Senior Scientists
Alex Dobkowski & Rod Meade, Senior Research Foresters
Weyerhaeuser Corporation
Richard Miller, Emeritus Soil Scientist
USDA Forest Service, PNW Station
Progress Update
We are now entering an exciting period in the project, as we will soon
be harvesting the study site and installing the experimental treatments.
At the present time, nearly all of the buffer areas surrounding the study
plots have been cut (Figures 1, and 2). 
The first treatments to be installed will be the bole-only harvest with
and without soil disturbance. Logs from all the plots will be removed by
reaching in with a shovel, taking care to avoid any traffic on the plot.
The exact procedure for simulating typical soil disturbance, including the
type of equipment used and the number and arrangement of passes through
the plot, is currently being worked out on nearby test plots. The four treatments
involving increasing levels of organic matter removal (bole-only, bole-only/mini-pile,
total-tree, total-tree plus) will subsequently be installed. All treatments
have been randomly assigned and will be replicated in each of the four blocks.
Following treatment installations
will be another round of summer fieldwork. This will involve assessing the
extent of soil disturbance by mapping the treatment plots and assigning
visual disturbance classes. The amount of organic matter retained on each
plot as slash, forest floor, and coarse woody debris will also be quantified
to estimate the effects that intensity of organic matter removal has on
total ecosystem nutrient pools.
Field sampling to estimate pre-harvest total nutrient pools has been completed and we are now concentrating on laboratory analyses. In addition to soil, forest floor, coarse woody debris, understory vegetation, and Douglas-fir above ground biomass, we have also sampled for Western Hemlock above ground biomass. Not only will this allow us to evaluate the contribution of this species to total ecosystem nutrient pools but will also be of further interest because little work has been done concerning fertilized Hemlock trees.
Questions? Please contact Rob Harrison, robh@u.washington.edu
or Barry Flaming, bflaming@u.washington.edu