but these
approaches lack an underlying basis for predicting future
changes. When one considers that atmospheric chemistry (e.g.,
ozone, CO2, NOx) and climate change may already affect forest
growth, the challenge of mapping potential forest productivity increases. Foresters, scientists, and policy makers would
therefore benefit if region-wide maps of potential forest
productivity were available at decadal intervals to record
changes, seek causes, and plan for the future.