Regeneration Abundance Analysis & Content Description

The regen.zip file contains all results pertaining to regeneration abundance estimates along the Appalachian National Scenic Trail and surrounding lands. This document is intended to provide a brief description of our analysis and a description of the contents of regen.zip. Contact Hunter Stanke at stankehu@msu.edu with questions.

Analysis description

We used the rFIA to package to estimate average live sapling abundance in trees per forested acre and basal area per forested acre, with associated sampling errors, within ecoregion subsections defined by the ecoregion/at_ecoSub.shp shapefile (see at_script.R for code). The ecoregion/at_ecoSub.shp shapefile includes polygons for ecological sections and subsections within Subregions within the conterminous United States clipped to the HUC10 shell surrounding the Appalachian National Scenic Trail.

We accessed subsets of the public Forest Inventory and Analysis database on 10 October 2019 for the following states: CT, GA, ME, MD, MA, NH, NJ, NY, NC, PA, TN, VT, and VA. We produced estimates for each FIA reporting year which was common among all states included in the analysis (2005-2016, with the exception of 2008). FIA data was not available for each ecoregion subsection defined by the ecoregion/at_ecoSub.shp shapefile. Attributes of ecoregions where FIA data was unavailable were preserved in results files (see results/) although estimated attributes are listed as NA for these rows.

File structure

• regen.csv: Estimates of live sapling (2.5 cm <= DBH < 12.7 cm) abundance (TPA & BAA) per forested acre
  • YEAR: FIA reporting year for current abundance estimates
  • TPA: estimate of mean saplings per acre
  • BAA: estimate of mean sapling basal area per acre
  • TPA_PERC: estimate of mean proportion of saplings which are live, with respect to TPA
  • BAA_PERC: estimate of mean proportion of saplings which are live, with respect to BAA
  • nPlots_TREE: number of non-zero plots used to compute tree and basal area estimates
  • nPlots_AREA: number of non-zero plots used to compute land area estimates
  • columns ending in SE: estimates of sampling error (%) of the respective variable. All sampling error estimates are computed with 68% confidence
  • other columns from ecoregions/at_ecoSub.shp
• regenS.csv: Estimates of live sapling (2.5 cm <= DBH < 12.7 cm) abundance (TPA & BAA) per forested acre grouped by species
  • Same as regen.csv, with following additional columns relating to species codes and names: SPCD, SCIENTIFIC_NAME, COMMON_NAME