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:

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