  Forest Inventory and Analysis (FIA) is a US Department of Agriculture Forest
Service program that aims to monitor changes in forests across the US. FIA
hosts one of the largest ecological datasets in the world, though its
complexity limits access for many potential users. rFIA is an R package
designed to simplify the estimation of forest attributes using data collected
by the FIA Program. Specifically, rFIA improves access to the spatio-temporal
estimation capacity of the FIA Database via space-time indexed summaries of
forest variables within user-defined population boundaries (e.g., geographic,
temporal, biophysical). The package implements multiple design-based
estimators, and has been validated against official estimates and sampling
errors produced by the FIA Program. We demonstrate the utility of rFIA by
assessing changes in abundance and mortality rates of ash (Fraxinus spp.)
populations in the Lower Peninsula of Michigan following the establishment of
emerald ash borer (Agrilus planipennis).
