Statistically-estimated tree biomass, stem density, and basal area for the upper Midwestern United States at the time of Euro-American settlement

Abstract

We present gridded 8 km-resolution data products of the estimated biomass, basal area, and stem density of tree taxa at the time of Euro-American settlement of the midwestern United States for the states of Minnesota, Wisconsin, Michigan, Illinois, and Indiana. The data come from settlement-era Public Land Survey (PLS) data (ca. 0.8-km resolution) of trees recorded by land surveyors. The surveyor notes have been transcribed, cleaned, and processed to estimate biomass, basal area, and stem density at individual points on the landscape. The point-level data are then aggregated within grid cells and statistically smoothed using a statistical model that accounts for zero-inflated continuous data with smoothing based on generalized additive modeling techniques and approximate Bayesian uncertainty estimates. We expect this data product to be useful for understanding the state of vegetation in the midwestern United States prior to large-scale Euro-American settlement. In addition to specific regional questions, the data product can serve as a baseline against which to investigate how forests and ecosystems change after intensive settlement. The data products (including both raw and statistically smoothed estimates at the 8-km scale) are being made available at the LTER network data portal as version 1.0.

Forest responses to last‐millennium hydroclimate variability are governed by spatial variations in ecosystem sensitivity

“…3, sensitivity slope = 0.065 SE 0.027). Reconstructed biomass variability (Fig 2., biomass reconstructions not available for the NEUS, (Paciorek et al ., 2019)) also was uncorrelated to drought variability (Table 1) and instead showed the highest variability at the historic prairie‐forest ecotone (Fig. 2) (Goring & Williams 2017).…”

“…ReFAB also employs a similar approach to STEPPS but focuses specifically on estimating total aboveground woody biomass (Raiho et al, 2020). ReFAB is calibrated using the relationship between settlement‐era multivariate pollen counts and biomass from PLS surveys (Paciorek et al ., 2019). Parameter estimates from calibration are then used to reconstruct centennially resolved biomass for 77 sites in the UMW for the last 10,000 years.…”