Objective measures of forest ecosystem condition are needed to gauge the ef
fects of management activities and natural phenomena on sustainability. The
Bioindicators of Forest Condition Project seeks to develop a Forest Condit
ion Rating (FCR) system using a physiological, remote sensing approach. In
particular, the goal of the project is to test whether hyperspectral remote
sensing may be used to infer stand-level information about pigment concent
ration, chlorophyll fluorescence, and other physiological features of condi
tion. The project spans a four-year period of intensive sampling in toleran
t hardwood forests in Ontario using the Compact Airborne Spectrographic Ima
ger (CASI). For each airborne campaign, concurrent ground-based sampling fo
r leaf physiological features was performed. Controlled laboratory and gree
nhouse studies were also conducted to derive relationships between leaf-bas
ed spectral measurements and physiology in the presence of environmental st
resses. The project has identified several promising bioindicators of strai
n that are discernible from hyperspectral images and related to ground-base
d physiology. The most promising remote indicator for semi-operational test
ing is estimation of chlorophyll content, which can be used to classify map
le stands on a five-stage scale of health. Chlorophyll fluorescence has als
o been discerned from spectral signatures, but our studies indicate it may
be confounded by chlorophyll content. The intent here is to update the fore
stry community on progress made, insights gained, and the practical implica
tions of the research.