USDA Forest Service

Forest Inventory and Analysis National Program


Forest Inventory & Analysis
National Office
U.S. Forest Service
1400 Independence Ave., SW
Washington, D.C. 20250-0003

(703) 605-4177

United States Department of Agriculture Forest Service.

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Program Features


Forest Health Indicators


Ozone Crown Condition Soil Quality Lichen
Down Woody Materials Vegetation Tree Mortality Tree Growth


Soil Quality Indicator


Soils represent the basic support system for terrestrial ecosystems because of their role in providing nutrients, water, oxygen, heat, and mechanical support to vegetation. Any environmental stressor that alters the natural function of the soil has the potential to influence the productivity, species composition, and hydrology of forest systems. In the Forest Inventory and Analysis (FIA) Program, we collect data to evaluate soil physical and chemical properties and the extent of erosion and compaction.

Why Is the Soil Quality Indicator Important?

Soil quality refers to the capacity of a soil to function within ecosystem and land use boundaries, to sustain biological productivity, maintain environmental quality, and promote plant and animal health (Doran and Parkin, 1994).

Information about soil chemical and physical properties can be used to answer the following types of questions about soil quality and forest health:


  • Can declines in forest productivity be correlated with changes in the availability of soil nutrients and water to plants?
  • What impacts are pollution (e.g., acid deposition) having on soil chemical properties?
    How much carbon is currently stored in forest soils and is this quantity changing over time?
  • What percent of U.S. forestland is impacted by soil compaction and soil erosion?

  • How much topsoil and forest floor material may be lost each year due to accelerated erosion?

Data from the soil quality indicator are not intended to be used alone when making statements about forest health. However, once the presence of a potential soil quality issue has been identified, these indicator data can be considered in association with other FIA measurements to assess the impact of soil quality on forest health.

Soil quality information contributes to the investigation of several key forest ecosystem concerns: (1) the productivity and sustainability of forest systems, (2) the conservation of soil and water resources, (3) the accumulation of persistent toxic substances, and (4) the contribution of forested systems to the global carbon cycle.

For more information about the Soil Quality Indicator visit our Soil Quality Indicator website or view the FIA Soil Quality Indicator Fact Sheet.

USDA Forest Service
Last Modified: January 26, 2005

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