Re: Aerial IR of Plants

["James Bielecki" <bieleckj@xxxxxxxxxxx>]

>Just a clarification. The amount of reflectance of the very near >infrared
>radiation (VNIR) by an individual leaf does not change much for >any
>stresses. From high up, a decrease in VNIR reflectance is due to >a change
>in the amount of leaf material observed per ground area. This >change in
>foliage density can be due to loss of leaves or drooping of >leaves, both of
>which can occur in stress.

Color IR photography is a major part of my summer time job.  We fly over large sections of Michigan's Upper and Lower Peninsulas (USA) photographing parts of Michigan's State Forest system.  We've found that a tree's particular IR signature will vary with time of year, time of day, the amount of defoliation, disease, drought, amount of stress, etc., etc.
 
CIR is indispensable for our type of work (Natural Resource management) but learning all of its subtleties hasn't been easy.  


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