Carbon Cycling Research at Silas Little Experimental Forest

Research Issue

An understanding of carbon, water, and energy exchanges between forests and the atmosphere at multiple scales in time and space is necessary to better inform decisions that are made concerning forest management, carbon sequestration, fire management, and the climate system.

Our Research

The major goal of this research is understanding and predicting carbon, water, and energy exchanges in response to climate variability, management, and disturbance.  These efforts are strongly aligned with the Northern Research Station RWU-6, Climate, Fire and Carbon Cycle Sciences problem areas. 

Three fire weather towers in the Pine Barrens of New Jersey are instrumented to measure atmospheric turbulence and eddy fluxes of energy, water vapor and carbon dioxide above the forest canopy using sonic anemometers and fast response gas analyzers.  These measurements are consistent with those made across 90 sites in the Ameriflux network and the North American Carbon Program.  We also make extensive forest biometric and hydrologic measurements at each site.  These measurements quantify key ecosystem services (e.g., carbon sequestration, water quantity, water and air quality).   By integrating carbon cycling research with ongoing projects in the Pine Barrens, we can address how forcing factors, such as climate change, invasive species, and atmospheric chemistry will alter important components of managed and unmanaged forest ecosystems.  Thus, we provide information on key characteristics of managed ecosystems and their vulnerability, resilience, and ability to offset negative impacts.  Our tower network is designed to contrast deciduous (Oak-dominated) vs. evergreen (Pine-dominated) stands, the most abundant upland forest types in the Pine Barrens.  These forest types also are widespread across the N. Atlantic Coastal Plain, thus we can address how impacts and responses develop over time in major forest types in the Eastern US.

Landscape-scale carbon, water, and energy fluxes for the New Jersey Pine Barrens

A tiered network of forest census measurements, termed “Tier 3” sites in the North American Carbon Program science plan, has recently been installed at the Forest.  This sampling network is intended to integrate the spatially intensive and highly resolved measurements made at the three flux tower sites with spatially extensive but coarsely resolved measurements made through remote sensing and forest inventory.  The sampling design involves a dense cluster of Forest Inventory and Analysis (FIA)-type plots located in the extended footprint around each flux tower.  The extended footprint includes the 1 x 1 km immediately surrounding the tower, plus a larger area of approximately 3 x 3 km (plots sampled in center of the 3 x 3 km (Skowronski et al. 2007).  These “benchmark” sites provide parameters and validation for ecosystem models, which in turn provide valuable information that is needed by decision-support tools for policy and management of forests on the Atlantic Coastal Plain.   In addition, we have integrated these data with long-term field plot data from FIA in New Jersey (Skowronski et al. 2007).  The Tier 3 study is capable of closing the regional carbon budget, i.e., accounting for all major exchanges of carbon between the land and atmosphere.

Quantifying the trade-offs between hazardous fuels management and carbon sequestration by forests. 

In conjunction with fuel reduction measurements, this network can be used to interpret hazardous fuel treatments in the context of regional forest carbon dynamics (Clark et al. in press).  Hazardous fuel reduction treatments are now mandated by the Healthy Forest Restoration Act of 2003, and our research helps clarify how management options result in tradeoffs between prescribed fires, wildfire risk, and carbon sequestration by forest ecosystems. 

Integration with simulation modeling groups. 

These include; Eastern Area Modeling Consortium (Fire weather predictions using MM5), USFS G-6 (PnET CN for forest productivity, NCAR Community climate system model for land surface parameters), Rutgers New Brunswick (BiomBGC for forest productivity), Rutgers Newark (Coupled carbon and hydrologic fluxes in forest ecosystems). 

Expected Outcomes

• Better understanding of how disturbances and landuse change impact net CO₂ exchange with the atmosphere and forest carbon dynamics over time.
• Development of a robust framework to scale intensive measurements made at the three flux tower sites to the landscape using remote sensing and forest inventory techniques.

Research Results

Clark, K. L., N. Skowronski, J. Hom, M. Duveneck, Y. Pan, S. Van Tuyl, J. Cole, M. Patterson, and S. Maurer.  2008.  Decision Support Tools to Improve the Effectiveness of Hazardous Fuel Reduction Treatments in the New Jersey Pine Barrens.  International Journal of Wildland Fire, In press.

Scheller, R. M., S. Van Tuyl, K. Clark, N. G. Hayden, J. Hom, and D. J. Mladenoff.  2008.  Simulation of Forest Change in the New Jersey Pine Barrens under Current and Pre-Colonial Conditions.  Forest Ecology and Management, In press. 

Hom, J., K. Clark, Y. Pan, S. Van Tuyl, N. Skowronski and W. Heilman.  Fire Research in the New Jersey Pine Barrens.  In, J. Qu, W. Sommers, A. Riebau, M. Kafatos, and R. Yang, eds. Remote Sensing and Modeling Applications to Wildland Fires, Springer-Verlag, In press. 

Skowronski, N., K. Clark, R. Nelson, J. Hom and M. Patterson. 2007.  Remotely sensed measurements of forest structure and fuel loads in the Pinelands of New Jersey. Remote Sensing of Environment 108: 123-129.  

Pan, Y., R. Birdsey, J. Hom, K. McCullough & K. Clark.  2006.  Improved estimates of net primary productivity from MODIS satellite data at regional and local scales.  Ecological Applications 16: 125-132.

Clark, K. L., J. Hom, and N. Skowronski.  2005.  Not So Barren (Summary of the NFP-funded project in the Pine Barrens).  Wildfire Magazine, May/June 2005, 14-17.

Powell, T. L., G. Starr, K. L. Clark, T. A. Martin, and H. L. Gholz.  2005.  Ecosystem and understory water and energy exchange for a mature, naturally regenerated pine flatwoods forest in north Florida.  Canadian Journal of Forest Research 35: 1568-1580.

Clark, K. L., H. L. Gholz and M. S. Castro.  2004.  Carbon dynamics along a chronosequence of Slash Pine plantations in North Florida.  Ecological Applications 14: 1154-1171.

Research Participants

Principal Investigator

• Kenneth L. Clark, US Forest Service Northern Research Station Research Forester
• John Hom, US Forest Service Northern Research Station Biological Scientist
• Nicholas Skowronski, US Forest Service Northern Research Station Research Forester

Research Partners

• Yude Pan, US Forest Service Northern Research Station Research Forester
• David Hollinger, US Forest Service Northern Research Station Plant Physiologist
• John Dighton, Pinelands Research Station, Rutgers University, NJ
• Ming Xu, Rutgers University, New Brunswick, NJ
• Richard Lathrop, Rutgers University, New Brunswick, NJ
• Karina Schaffer, Rutgers University, Newark, NJ
• Robert Nicholson, USGS
• J. Chen, University of Toledo, OH