DOI: 10.5061/dryad.xpnvx0khn
title: Bioclimatic, soil, terrain, distance to Native American settlement, and historical tree taxon relative abundance data at 8-km resolution for the northeastern United States

description: Researchers have debated impacts of past Native American land use on
 forests including upon tree species composition in northeastern United
 States (US), with estimates of impacts ranging from local to regional
 extent. This study examines tree relative abundances in
 the northeastern US (approx. 420,000 km2) to
 assess whether Native Americans influenced geographic distributions of 18
 tree taxa prior to Euro-American settlement. We used boosted
 regression trees to model abundance patterns and to assess the importance
 of distance-based proxies of Native American land use versus environmental
 variables. We trained models that included and excluded distance-based
 proxies. Abundance estimates from original land survey records (1650-1850
 CE) were acquired for taxa at 8 km spatial resolution, and related to
 Native American settlement locations (1500-1800 CE) and 27 environmental
 variables. When evaluated upon test data, regional-scale models
 of relative abundance that included distance-based proxies performed only
 slightly better than models that excluded them, with mean improvements in
 RMSE of 0.1 percentage points. Models suggest that Native American land
 use modestly altered the relative abundance of taxa locally, extending no
 more than 50 km from settlement. Models also suggest slight increases near
 settlement of a few percentage points in relative abundance for
 fire-tolerant and/or dietary taxa (e.g. oak, hickory, and pine), and for
 early-successional taxa (e.g. ash). Past Native American
 land use had no detectable effect on forest composition across a regional
 extent, but increased the abundance of fire-tolerant, shade-intolerant,
 and nut-producing trees locally. The Excel-format (.xlsx) dataset here
 provides the training and testing data for the BRT models in this
 publication. It contains relative abundances of the 18 tree taxa expressed
 as a fraction of total number of trees. It also provides bioclimatic (e.g.
 annual temperature, annual preciptation), soil (e.g. pH, percent sand),
 terrain (e.g. slope), and Native American (e.g. distance to settlement)
 variables developed from multiple sources. A column also indicates whether
 an observation was part of the training data or the test data. See the
 publication and its Supporting Information for full details on the
 acquisition and processing of these data, as well as the original
 providers of the data. If using these data, please cite both this
 dataset's corresponding article, as well as the original providers of
 the data. Also provided are ascii-format (.asc) gridded data layers that
 were used for making spatial predictions of taxon relative abundances from
 BRT models. The original creators/providers of the relative abundance,
 bioclimatic, soil, terrain, and Native American data or layers used for
 creating the gridded data in this study are: Abel, T. (2016). The
 Iroquoian occupations of Northern New York: A summary of current research.
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 Nations in New Brunswick. Comitas Institute for Anthropological Study.
 http://cifas.us/first-nations-maps/  Grumet, R. S. (1995).
 Historic Contact: Indian People and Colonists in Today’s Northeastern
 United States in the Sixteenth through Eighteenth Centuries. University of
 Oklahoma Press. Jordan, K. A. (2013). Incorporation and colonization:
 Postcolumbian Iroquois satellite communities and processes of indigenous
 autonomy. American Anthropologist, 115(1), 29–43. Milner, G. R., &
 Chaplin, G. (2010). Eastern North American population at ca. A.D. 1500.
 American Antiquity, 75(4), 707–726. NASA. (2000). SRTM 90m Digital
 Elevation Database v4.1.
 https://cgiarcsi.community/data/srtm-90m-digital-elevation-database-v4-1/  O’Donnell, M. S., & Ignizio, D. A. (2012). Bioclimatic Predictors for Supporting Ecological Applications in the Conterminous United States (Data Series 691; p. 10). U.S. Geological Survey. https://www.sciencebase.gov/catalog/item/4fe0f9f4e4b05d4ed81d9392  Paciorek, C. J., Goring, S. J., Thurman, A. L., Cogbill, C. V., Williams, J. W., Mladenoff, D. J., Peters, J. A., Zhu, J., & McLachlan, J. S. (2016). Statistically-estimated tree composition for the northeastern United States at the time of Euro-American settlement. PLoS ONE, 11(2), e0150087. https://doi.org/10.1371/journal.pone.0150087  Peters, M. P., Iverson, L. R., Prasad, A. M., & Matthews, S. N. (2013). Integrating Fine-scale Soil Data into Species Distribution Models: Preparing Soil Survey Geographic (SSURGO) Data from Multiple Counties (General Technical Report NRS-122; p. 70). U.S. Forest Service. https://www.fs.usda.gov/treesearch/pubs/45308