Progress Report March 4, 1998

Hart, Stephen

NCEAS Sabbatical Fellow 8/1/97 – 7/31/98

Title of Activity:

Analysis and Synthesis of the Historical Range of Variability in Ecosystem Structure and Function of Inland West Forests - Implications for Ecological Restoration

Original proposal abstract

Management activities such as fire suppression, overgrazing, and selective logging since Euro-American settlement of the Inland West have resulted in forest ecosystems that are in a poor ecological condition. Current proposals to restore these forest ecosystems to their presettlement conditions suffer from the lack of a comprehensive assessment of the historical range of variability in ecosystem structures and functions of these forests. As a Resident Fellow at NCEAS on sabbatical leave from Northern Arizona University, I propose to conduct a comprehensive analysis and synthesis of the current state of knowledge regarding the historical range of variability of forest ecosystems of the Inland West. This analysis will include published manuscripts in professional journals, public documents from land management agencies, and unpublished data contained in graduate student theses or archived in researchers' databases. Other quantitative data such as those from early land survey records or qualitative data such as repeat photography will also be collected and analyzed. Process-based ecological simulation models will be used to assess changes in ecological attributes since Euro-American settlement, and to predict alterations in these attributes following restoration treatments (such as thinning and prescribed burning). Existing experimental data will be used to help verify simulation predictions. This comprehensive synthesis will aid land managers in predicting the potential impact of restoration efforts on ecosystem health in different forest-types, and evaluate the transportability of restoration practices across forests of the Inland West.


Soon after I arrived at NCEAS, I realized that I would be unable to complete all the tasks that I had proposed for my sabbatical activity while in residence at NCEAS. Hence, I decided to focus my work on the application of process-based ecological simulation models for the estimation of the historical range in variability of ecosystem function in the ponderosa pine forest type. I chose the ponderosa pine type mainly because I am familiar with this ecosystem, and I am currently involved in experimental efforts at restoring these forests in the Southwest.

Since arriving at NCEAS, I also have become aware that the computer simulation models available to reconstruct ecosystem function may be inadequate for fire-evolved forests that have important understory (bunchgrasses, forbs, shrubs) and overstory (pine trees) components. I have been working closely with Dr. Robert Keane at the USFS Fire Laboratory, Missoula, Montana, in developing a new version of FIRE-BGC that can be run at the stand level, and that has all the necessary components. I visited with Dr. Keane in Missoula once last fall to initiate this collaboration. Unfortunately, the current BGC code of the model (from Dr. Steven Running’s research group at University of Montana, Missoula) is new and apparently unstable. Hence, it is unlikely that I will be able to apply this model to my data sets until the summer at the earliest. As a result, I have begun parameterizing Forest-BGC and the soil organic model "Century" (in the Savannah mode) for the existing stand data I have assembled for ponderosa pine (about 6 locations). I hope to secure a version of BIOME-BGC in the near future to aid in the simulation of the understory (primarily bunchgrasses) component of these forests as part of my Forest-BGC effort.

After I finish my simulations for the ponderosa pine sites with these existing models, I plan to attempt to validate these model runs with the available field data. I then will move on to similar simulations for at least one other Inland West forest type (lodgepole pine, mixed-conifer, or spruce-fir).

Being at NCEAS has facilitated my activity in many ways. I have been able to interact with some of the developers of the models I am using (i.e., Drs. Steven Running. Lars Pierce, and Bill Parton) because they have "passed through" NCEAS as part of other activities held here. The computer support also has been excellent and timely. Finally, the fact that I am not working in a colleague’s laboratory for my sabbatical that would entice me to collect MORE data has been extremely helpful in my synthetic efforts. By being here at NCEAS away from all data production tools, I am forced to analyze and synthesize existing information.

Accepted abstracts:

Hart, S.C., W.W. Covington, and M.M. Moore. 1998. Analysis and synthesis of the historical range of variability in ecosystem structure and function of Inland West forests: implications for ecological restoration. To be presented at the Ninth North American Forest Soils Conference, Aug. 9-14, Tahoe City, CA.

Manuscripts accepted or submitted to peer-reviewed journals acknowledging NCEAS support:

Hart, S.C., and D.A. Perry. In press. Transferring soils from high- to low-elevation forests increases nitrogen cycling rates: climate change implications. Global Change Biology.

Hart, S.C. In review. Leaching of inorganic nitrogen and phosphorus from the forest floor of old-growth conifer forests. Canadian Journal of Forest Research.

Hart, S.C. In review. Net nitrogen transformations in decayed logs and mineral soil of an old-growth forest. Ecology.

Hart, S.C., and P. Sollins. In review. Soil carbon and nitrogen pools and processes in an old-growth conifer forest 13 years after trenching. Canadian Journal of Forest Research.