Mapping the historical extent of forest cover in 1910 on the Longleaf Pine Ridge, Jasper and Newton Counties, Texas

Historical mapping using a geographical information system (GIS) is a relatively new application. Thus, the methodology behind this application should be fine tuned into acceptable standards for historic mapping products. The objective of this study was to reconstruct historical forest cover, in a GIS, for the Longleaf Pine Ridge in eastern Texas. The Longleaf Pine Ridge Conservation area covers 194,677 ha (481,047 ac) in the West Gulf Coastal Plain or "Pineywoods" ecoregion of Texas (Halstead 2002). The study area was determined by Temple-Inland Forest Products Corporation and located in northern Jasper and Newton Counties. Data were provided by Tobin International and the 1910 Houston Oil and Gas survey.; For the purposes of this study, maps from the 1910 inventory were georeferenced to a current land abstract shapefile of the area. Then these 1910 maps were digitized into cover type categories and converted into raster form. Inverse distance weighting (IDW) interpolation method was used on the study area to compose an interpolated surface of cover types. The IDW was run on pine volume per acre and hardwood volume per acre from the 1910 map tables. These continuous surfaces were then combined to form a ratio of hardwood to pine volume across the study area. The resulting ratio raster was classified into categorical cover types and then subtracted from the 1910 raster for validation. The result was a 67% match of cover type classification. This result was good considering the age of the forest inventory maps that were provided. The end result is a product that can be used in future land management decisions for this area.