Category: General Publications
Title: Ponderosa Pine Forest Reconstruction: Comparisons With Historical Data
Author: * Huffman, D.W. , Moore, M.M. , * Covington, W.W. , * Crouse, J.E. , * Fule, P.Z.
Subject: Dendroecology, Pre-settlement, Ponderosa pine (Pinus ponderosa)
Abstract: Dendroecological forest reconstuction techniques are used to estimate presettlement structure of northern Arizona ponderosa pine forests. To test the accuracy of these techniques, we remeasured 10 of the oldest forest plots in Arizona, a subset of 51 historical plots established throughout the region from 1909 to 1913, and compared reconstruction outputs to historical data collected. Results of this analysis revealed several distinct sources of error: (1) After about 90 years, 94 percent of the recorded trees were relocated and remeasured, but approximately three trees/ha were missing in the field due to obliteration by fire or decay; (2) sizes of trees living in 1909 were overestimated by an average of 11.9 percent; (3) snag and log decomposition models tended to underestimate time since tree death by an undetermined amount; and (4) historical sizes of cut trees were difficult to estimate due to uncertainties concerning harvest dates. The aggregate effect of these errors was to overestimate the number of trees occurring in 1909-1913. Sensitivity analysis applied to decomposition equations showed variations in reconstructed sizes of snags and logs by +/- 7 percent and stand density estimates by 7 percent. Results suggest that these reconstruction techniques are robust but tend to overestimate tree size and forest density.
Source: USDA Forest Service Proceedings RMRS-P-22
Publisher: USDA Forest Service, Rocky Mountain Research Station, http://www.fs.fed.us/rmrs/