Insights Into Fire-based Soil Temperature and Moisture Changes From a
Long-term Data Set in Alaska
Abstract
Wildfires are one of the main sources of disturbance in boreal forests.
Post-fire changes to soil temperature and moisture regimes can have
wide-ranging impacts on boreal forests including the depth at which
permafrost is found, vegetation recovery, and carbon and nitrogen
cycling. Surface soil temperatures increase following fire, due to loss
of shading from tree canopies and a thinner surface organic layer.
Post-fire soil temperature and moisture regimes also change due to
reduced transpiration and changes in surface albedo. The duration of
these changes depends on factors such as region, fire intensity, and
soil texture. Here we present results from a long-term (1999 to present)
dataset of soil conditions for four black spruce boreal forest sites
located in Interior Alaska across burn and permafrost gradients: 1)
burned, no permafrost, 2) unburned, no permafrost, 3) burned, with
permafrost, and 4) unburned, with permafrost. The data from these sites
demonstrate how both burning and the presence of permafrost influence
soil temperature and moisture, as well as the timing of seasonal
changes, for over twenty years. In addition, we discuss the challenges
of maintaining and collecting data from field instruments deployed for
decades in harsh conditions. All data discussed in this presentation
will be available on the Bonanza Creek Long-term Ecological Research
(LTER) website and is available for future studies.