Using a mensuration approach with FIA vegetation plot data to assess the accuracy of tree size and crown closure classes in a vegetation map of northeastern California

The accuracy of the Lassen-Modoc vegetation map was assessed using data fro m a grid of permanent Forest Inventory and Analysis (FIA) plots in conjunct ion with a fuzzy logic approach. This paper presents the results for the Mo doc National Forest. The main foci of this paper are the methods and result s for assessing the accuracy of tree size and crown closure classes using a mensurational approach based on calculations made from the plot data. Tl,i s approach proved very useful in conjunction with fuzzy accuracy methods. H igher error rates reported for crown closure classes may be due to a variet y of factors including error associated with crown closure modeling methods , error associated with crown closure calculations for a plot, and the vari ability of crown closure within a plot. Using the FIA data has proven to re present a cost-effective,means of generating accuracy assessment informatio n based oil a probability sample. (C) Elsevier Science Inc., 2000.