Note that the data published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution. For the most recent data, purchase the 2008 Report from Island Press.

Please see the technical note for Forest Area and Ownership, which also serves as the technical note for the Forest Types indicator.

2003 Web Site Update: During the process of updating the data in this indicator, it was decided that a more objective method was needed to determine whether a forest type had increased, decreased, or remained the same over a period of time. For the 2002 report, a simple comparison was used between the first and last time points (i.e., 1963 and 1997) to make a decision about trend. A new method has been implemented whereby a trendline was fit to the time series for a given forest type, an r value computed, and then this r value was compared to the appropriate P value to establish whether or not the slope of the trendline was significantly different from zero. Only those data series that had a significantly positive or negative trendline were reported as such for this data update. It is the expectation that this method will be used in future iterations of this report. Data for 2002 were added in this update. Data were acquired from the forest service and available on the Web at http://fia.fs.fed.us.