Quantifying old-growth forest of United States Forest Service public lands: Supporting code

These files provide code used to attribute old growth status to forest inventory and analysis (FIA) samples ('conditions') in National Forest System regions. To generate estimates of acres of old growth and standard errors, the designation of old growth was appended to the public FIA database and we ran a standard area estimate. See "FIA area estimate example" in this data archive.The manuscript provides supplemental information used by the code, such as criteria and crosswalks from FIA data to regional old growth forest types/vegetation groups, to calculate old growth status in each region. These files provide code used to attribute old growth status to forest inventory and analysis (FIA) samples ('conditions') in National Forest System regions. The code uses public FIA data, available at https://apps.fs.usda.gov/fia/datamart/datamart.html, and supplementary confidential information in some regions (such as geographic information extracted using real coordinates, and modeled tree ages). See "FIA evaluations list" for the complete list the state and years of data used for this work. See "FIA evaluations list" for the complete list the state and years of data used for this work.