Jeffrey A. Wolf,^1,4 Stephen P. Hubbell,^1,2 Geoffrey A. Fricker,³ Benjamin L. Turner²

¹ Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA ([email protected], [email protected])

² Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Republic of Panama ([email protected])

³ Department of Geography, Bunche Hall, University of California, Los Angeles, CA 90095, USA ([email protected])

⁴ Corresponding author. E-mail: [email protected].

corners.csv (MD5: 00b9af230a2cd73315d473083f6e7647)

soils.csv (MD5: d4deb84fa3a2300097efc07a7a42700c)

standards.csv (MD5: bdeb50c58864228f02b06be2971d11dc)

afproj-master.zip (MD5: 30f8248abbe2851dd2b5763933ca6165)

At plot scales (<1 km²) used to study tropical forest plant communities the causes of spatial heterogeneity of soils are disputed. We collected, georeferenced, and chemically analyzed a large spatial sample of soil cores (n = 625 sites, 6.25 cm diameter × 10 cm depth cores) on an approximately 28 m regular grid from the Barro Colorado Island (BCI) 50-ha (0.5 km²) forest dynamics plot (FDP), Republic of Panama (9.15° N, 79.8° W). Here we present these data for general use. We also present differential GPS measurements of the plot corners for the BCI 50-ha FDP, which aid in geospatial research in one of the most studied tropical forests. Further, we present a free open source command line software program written in Python that allows point data referenced to the plot coordinate system to be converted to a projected coordinate reference system for geospatial research. Together, the data sets allow for testing the drivers of soil heterogeneity in a tropical tree community using a wide variety of geospatial data sources.

Key words: Barro Colorado Island; biodiversity; biogeochemistry; Geographic Information Systems; nutrients; remote sensing; spatial projection; soil.