Settlement-era public land survey data: Six Rivers National Forest

Historical baselines of forest conditions provide reference states to assess how forests have changed through time. In California, the Public Land Survey System (PLSS) provides tree inventory data between 1872-1884 at 93.2 km2 (36mi2) resolution. Although these data provide a spatially extensive record of settlement-era forest conditions, reconstructions using PLSS data have been limited and controversial in western landscapes. Recent improvements in the application of plotless density estimators (PDE) have made reconstructions more accurate and robust. The purpose of this study was to use PDE to reconstruct the settlement-era forest conditions in Six Rivers National Forest – a floristically diverse temperate forest in the Klamath Mountains of northwestern California – to quantify differences with modern conditions. Records of fires and harvests were used in conjunction with the PLSS data to understand the influence of forest management during the previous century. The contemporary fore...