Mt. Termikaelian et Rg. Wagner, DISTANCE-INDEPENDENT MODELS FOR PREDICTING PHOTOSYNTHETICALLY ACTIVE RADIATION TRANSMISSION THROUGH YOUNG FOREST PLANT CANOPIES, Canadian journal of forest research, 27(1), 1997, pp. 127-130
We developed two distance-independent models for predicting photosynth
etically active radiation (PAR) transmission through young forest plan
t canopies. The two models (model 2, using individual-plant crown area
, and model 3, using species cover) were derived from a more complex i
ndividual-plant, distance-dependent model (model 1) described in an ea
rlier study. Models 2 and 3 require fewer data inputs and can be used
when detailed data on individual plants are not available and (or) spa
tially explicit predictions of PAR transmission are not of interest. W
e found close agreement between PAR transmission values between model
1 and models 2 and 3 using data from a plant density study. Mean predi
ction errors between models 1 and 2 were 0.34% and 1.09% for two plant
species studied. Mean prediction errors between models 1 and 3 were 0
.77% and 2.58% for the two plant species studied. The extinction coeff
icients estimated from model 1 were used successfully in models 2 and
3 without additional calibration.