Development of Critical Loads and Critical Load Exceedance Maps for Protecting California Ecosystems from Atmospheric Nitrogen Deposition
More than 50,000 km2 of the land area in California receive atmospheric deposition inputs of at least 10 kg N/ha/yr. Many ecosystems are negatively affected by these elevated N inputs. The purpose of this research was to develop critical loads (CLs) as a management tool for reducing the impacts of chronic N deposition. Critical loads are defined as the air pollution deposition threshold below which harmful ecological effects do not occur according to present knowledge. In this work, CLs for nitrogen (N) deposition were developed for seven major vegetation types in California. An N deposition map for the entire state of California was developed and N CL exceedance maps for California were produced by overlaying vegetation maps, CL values and N deposition data.
Involved in this R & D were personnel from Region 6, PSW and PNW of the Forest Service; University of California, Arizona and Alaska; and a private consultant. Forest Inventory and Analysis (FIA) Program lichen biomonitoring data were widely used in developing this product.
Forest Service Partners