Use of Ancillary Data to Improve the Analysis of Forest Health Indicators

In addition to its standard suite of mensuration variables, the Forest Inventory and Analysis (FIA) program of the U.S. Forest Service also collects data on forest health variables formerly measured by the Forest Health Monitoring program. FIA obtains forest health information on a subset of the base sample plots. Due to the sample size differences, the two sets of variables have traditionally been analyzed separately. However, the analysis of forest health indicator data can occur in conjunction with not only other stand characteristics (mensuration variables such as live-tree volume), but also with a plethora of ancillary information such as climate data and satellite imagery. This document is designed to help people interested in using auxiliary information in the analysis of the forest health indicators. Readers are initially treated to topics related to exploratory data analysis. This introductory content is followed by presentation of various statistical methodologies that may be employed; each section provides empirical analyses and discussion of the technique being presented. To cultivate a common theme throughout the document, carbon attributes of coarse woody debris (i.e., downed deadwood of a minimum size) is used as the forest health variable of interest; however, the underlying concepts can be applied to analyses of other variables as well.