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Sustaining Forests

Linking Wood Stake Decomposition in the Forest Floor and Mineral Soil with Soil Productivity in the Northern Research Station

[photo:] Collecting dta on wood stake decay rates over time from a site in Baltimore.  Photo by Ian Yesilonis, US Forest Service.Research Issue

Soil organic matter is key to maintaining site productivity because of its roles in soil water availability, nutrient supply, soil aggregation, and disease incidence or prevention. Organic matter decomposition is controlled by the same soil factors that affect plant growth - water, nutrients, temperature, and pH. Forest management practices and other land management activities can greatly affects organic matter decomposition, which could affect tree growth and site productivity. Consequently, organic matter decomposition is being used as an index of forest management effects (both positive and negative) in long-term soil productivity studies being conducted in various parts of North America and Canada. Projected climate change scenarios and changes in land use would also have a pronounced effect on soil organic matter decomposition rates.

A number of study sites investigating wood decomposition have been established across the United States, Canada, and internationally. The first such field sites were part of the Long Term Soil Productivity (LTSP) network established by the U.S. Forest Service to investigate possible forest management effects on long-term soil productivity in different forest regions of the United States. Additional study areas throughout the U.S., Canada, and Europe represent a wide variety of soil types and climatic conditions, and most are being monitored for soil moisture and temperature. Soil chemical and physical properties have also been characterized on each of these sites. Various management treatments have been applied, which reflect the impact of timber harvesting, site preparation, or wildfire. However, few of these wood decomposition study sites currently exist within the Northern Research Station. Also, there are questions specific to the region within NRS boundaries regarding carbon cycling that can be addressed through a NRS-centric study. 

Our Research

This research has the following objectives: 1) Evaluate the effects of soil chemical, physical, and biological properties on wood decomposition rates and microbial decay patterns across a range of soil types and climatic regimes within the Northern Research Station. 2) Estimate the impacts of a variety of land management practices (e.g. timber harvesting, site preparation, urbanization, and wetland restoration) on wood decomposition in the forest floor and mineral soil within the Northern Research Station. 3) Assess the relationship of microbial diversity to the rate and degree of wood decomposition under varying soil moisture, temperature, and nutrient conditions within the Northern Research Station.

Expected Outcomes

We will collect data that reflect the different decomposition rates from a variety of diverse ecosystems.  Wood decomposition study plots have been established at eight locations across the Northern Research Station. Four are the NRS Long Term Soil Productivity sites in Michigan, Minnesota, Missouri, and West Virginia.  We will also establish sites on the Baltimore Ecosystem Study (both urban and non-urban forests); on a hydrologically restored forested wetland near Somerset, MD; and in Kissena Corridor Park in Queens, NY. These sites were selected because they cumulatively represent a broad gradient of soil type, temperature, and moisture; they also represent a variety of forest types, including sites undergoing restoration activities found across the Northern Research Station. 

Research Results

Wood stakes were installed in all of the sites in 2012-2013, and each year wood stakes have been retrieved and analyzed for changes, creating information on decay rates over time at each site.  With existing site information, we will be able to model decay over time as a function of climate, soils, vegetation type, and the treatments at each site. 

Research Participants

Last Modified: February 6, 2017