Ohio Public Land Survey (PLS) Witness Tree GIS Shapefile

The United States Public Land Survey (PLS) divided land into one square
mile units, termed sections. Surveyors used trees to locate section corners
and other locations of interest (witness trees). As a result, a systematic
ecological dataset was produced with regular sampling over a large region
of the United States, beginning in Ohio in 1786 and continuing westward.
We digitized and georeferenced archival hand drawn maps of these witness
trees for 27 counties in Ohio. This dataset consists of a GIS point
shapefile with 11,925 points located at section corners, recording 26,028
trees (up to four trees could be recorded at each corner). We retain species
names given on each archival map key, resulting in 70 unique species common
names. PLS records were obtained from hand-drawn archival maps of original
witness trees produced by researchers at The Ohio State University in the
1960’s. Scans of these maps are archived as “The Edgar Nelson Transeau Ohio
Vegetation Survey” at The Ohio State University: http://hdl.handle.net/1811/64106.
The 27 counties are: Adams, Allen, Auglaize, Belmont, Brown, Darke,
Defiance, Gallia, Guernsey, Hancock, Lawrence, Lucas, Mercer, Miami,
Monroe, Montgomery, Morgan, Noble, Ottawa, Paulding, Pike, Putnam, Scioto,
Seneca, Shelby, Williams, Wyandot. Coordinate Reference System:
North American Datum 1983 (NAD83). This material is based upon work supported by the National Science Foundation under grants #DEB-1241874, 1241868, 1241870, 1241851, 1241891, 1241846, 1241856, 1241930.