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Title: A NATIONAL APPROACH FOR MONITORING PHYSICAL AND CHEMICAL INDICATORS OF SOIL QUALITY OF U.S. FORESTLANDS AS PART OF THE FOREST INVENTORY AND ANALYSIS PROGRAM

Author
item O Neill, Katherine
item AMACHER, MICHAEL - USDA FOREST SERVICE
item PALMER, CRAIG - UNIV OF NEVADA LAS VEGAS

Submitted to: Environmental Monitoring and Assessment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/2004
Publication Date: 8/22/2005
Citation: O Neill, K.P., Amacher, M., Palmer, C. 2005. A national approach for monitoring physical and chemical indicators of soil quality of U.S. Forestlands as part of the Forest Inventory and Analysis program. Environmental Monitoring and Assessment 107 (1-3): 59-80.

Interpretive Summary: The Montreal Process was formed in 1994 to develop an internationally agreed upon set of criteria and indicators for the conservation and sustainable management of temperate and boreal forests. In response to this initiative, the Forest Inventory and Analysis (FIA) and Forest Health Monitoring (FHM) programs of the United States Department of Agriculture Forest Service have recently implemented soil measurements as part of a national monitoring program to address specific questions related to the conservation of soil and water resources. As the only repeated, systematic sampling of soil properties on all forestlands of the U.S. regardless of ownership, the FIA/FHM soil program provides critical baseline information on the status of forest soils that can be used to meet regional, national, and international reporting requirements on sustainable forest management. This paper presents an overview of the FIA/FHM soil monitoring program and outlines the field and laboratory protocols as currently implemented. To demonstrate the relevance and utility of the soil monitoring program in assessing forest sustainability, available data from the FIA/FHM soil indicator (1998-2001) were analyzed with regards to three of the indicators in the Montreal Process: (1) accelerated erosion, (2) surface compaction, and (3) changes in soil chemical properties. Modeled erosion rates on undisturbed forestland were generally small, with 85% of the 667 plots modeled having potential erosion rates of less than 0.05 t ha-1 under average precipitation events (2-yr return interval). Following a more severe precipitation event (100-yr storm), modeled erosion rates increased, with 30.6 percent of plots having a modeled erosion rate greater than 0.5 t ha-1 (median 0.07 t ha 1). Although the potential for erosion was greater under more extreme climate events, these mean erosion losses were still an order of magnitude smaller than the 6.9 t ha-1 y-1 estimated for agricultural lands (1997 National Resources Inventory). Evidence of surface compaction was primarily a localized phenomena with more than 86% of the 2006 plots measured during this time period reporting only trace levels of soil compaction (< 5% of the plot area). Initial data collected from 2000 to 2002 indicate that pH values were significantly lower in the eastern United States (North and South RPA regions) than in the western U.S.. Similarly, median values for the ratio of calcium to aluminum were an order of magnitude higher in the Rocky Mountain (999.5) and Pacific Coast (311.6) regions than in either the North (4.4) or South (3.1) regions. These patterns generally reflect the higher levels of precipitation in the east which tend to result in increased leaching of base cations (a reduction of Ca2+ relative to Al3+), increased soil weathering, and a reduced buffering capacity for acidic inputs. Integration of soil assessments into the framework of the national FIA/FHM program provides a mechanism for systematic monitoring of soil properties across all forested regions of the U.S. using nationally-standardized collection, preparation, and data distribution formats that are fully compatible with existing forest inventory and forest health data. However, additional research is still needed to determine appropriate baselines and thresholds for assessing forest health and linking plot measurements to the underlying processes regulating forest productivity and ecological function.

Technical Abstract: The Montreal Process was formed in 1994 to develop an internationally agreed upon set of criteria and indicators for the conservation and sustainable management of temperate and boreal forests. In response to this initiative, the Forest Inventory and Analysis (FIA) and Forest Health Monitoring (FHM) programs of the United States Department of Agriculture Forest Service have recently implemented soil measurements as part of a national monitoring program to address specific questions related to the conservation of soil and water resources. As the only repeated, systematic sampling of soil properties on all forestlands of the U.S. regardless of ownership, the FIA/FHM soil program provides critical baseline information on the status of forest soils that can be used to meet regional, national, and international reporting requirements and will prove a valuable resource for scientists and managers concerned with conservation and sustainable management. This paper presents an overview of the FIA/FHM soil monitoring program, outlines the field and laboratory protocols as currently implemented, and provides examples of how these data may be used to assess indicators of sustainable management as defined by the Montreal Process. Challenges of interpreting plot information at regional and national scales are identified.