Fires are a major controlling factor in the ecology of most, if not all, boreal forests. It has been shown that fires result in dramatic changes in the ground layer temperature of boreal forests for 15 to 30 years. This temperature increase is due to several factors, including: a reduction of shading which results in an increase in direct solar insolation; a reduction of the depth of the moss/litter/organic soil depths, which serve to insulate the ground; and a decrease in surface albedo. In areas underlain by permafrost, the depth of the summer active layer increases significantly, which in turn alters the moisture regime of the ground layer. The large majority of area burned in boreal forests (which has averaged 3.3 million ha in North America over the past decade) occurs in large fire events. Over 90% of the area burned in North American boreal forests occurs in fires larger than 10,000 ha. There are many fires >100,000 in size and some fires approach 1 million ha in size. Monitoring the effects of these fires present a unique challenge because of not only their size, but the fact that the effects change throughout the growing season due to variations in climate conditions. Over the past several years, research has been conducted on using satellite remote sensing instruments to monitor fire- disturbed boreal forests in Alaska and Canada. In this paper, we will illustrate how spaceborne imaging radar systems can be used to monitor spatial and temporal variations in soil moisture and how thermal infrared systems can be used to monitor variations in surface temperature.

Environmental Research Institute of Michigan
Nancy H.F. French
P.O. Box 134001
Ann Arbor, MI 48113-4001
Fax: 313 994 5824
E-mail: french@erim.org