Verbyla, D. and R. Lord. 2008.
Estimating post-fire organic soil depth in the Alaskan boreal forest
using the Normalized Burn Ratio
International Journal of Remote Sensing. (in press)
Abstract. As part of a long-term moose browse/fire severity study, we used the Normalized
Burn Ratio (NBR) with historic Landsat Thematic Mapper (TM) imagery to
estimate fire severity from a 1983 wildfire in interior Alaska. Fire severity was
estimated in the field by measuring the depth of the organic soil at 57 sites during
the summer of 2006. Sites were selected for field sampling from five fire severity
classes based on threshold NBR values. The linear relationship between post-fire
NBR and organic soil depth among sites within the burn was weak (r250.26),
and improved substantially (r250.66) when restricted to non-wetland black
spruce sites. The relationship between NBR and aspen/willow counts was nonlinear.
Sites with high densities of aspen stems consistently occurred in the high
fire severity classes, and sites with high willow stem densities consistently
occurred in the moderate fire severity class. However, NBR varied substantially
from sites with low aspen or willow reproduction and therefore predicting aspen
or willow regeneration based on post-fire NBR values would be difficult.
Email: D.Verbyla@uaf.edu
Last updated:
January 2008