Heamit,
Just to follow up on my earlier reply to you, I did a quick exploration of a small part of the northern edge of beaver distribution. The results are attached. This example shows a North- South transect which I quickly scanned in a strip of high resolution digital globe and terra metrics imagery. I started in the south and worked my way up. The most northern point of beaver observed is the last placemark. Most of this area is permafrost, peatplateaus in the south, peat polygones in the North. A sub arctic environment. A very meager food supply for beaver.

The orange colors represent wildland fires most 3-10 years old. The darker spot are fires that were burning during the year the images were taken. Some are burning - smoking in the high resolution strips.

I did my thesis fieldwork here over 30 years ago (Automated Interpreation of Satellite and Multi-spectral Airborne Imagery for Biophysical- Ecological Land Classification) Unfortunately I did not focus on beavers at that time. Too Bad.

More information on fire interpretation:

http://www.geostrategis.com/p_borealfires.htm

http://www.geostrategis.com