Spatial patterns of burn severity under changing fire regimes

Even large forest fires are extraordinarily heterogeneous in how they burn; that is, they produce a complex mosaic of severely burned patches intermixed with unburned islands and lightly burned areas. This heterogeneity is critical to post-fire forest response (e.g., ability to disperse seed from unburned patches), yet the mechanisms that produce these patterns are not fully understood. Further, patterns may be changing as fire regimes are changing (e.g., increased frequency, severity, or size of fires). We are using hundreds of field plots across the Rocky Mountains and the Pacific Northwest where we have intensive measures of burn severity (e.g., tree mortality, soil charring) to calibrate satellite indices of burn severity. We are then using these calibrated satellite maps of burn severity to ask the following questions:

1) How well do satellite indices of burn severity perform across gradients of latitude, topography, stand structure, and pre-fire insect outbreaks? Further, can satellite indices accurately measure burn severity in short interval “reburns” that are becoming common throughout the western US?

2) What are the drivers of landscape patterns of burn severity (e.g., patch size and shape of different forests burned at different severity)? Do those drivers vary within and among regions?

3) Are the landscape patterns of burn severity different in short-interval reburns than in long-interval fires?

 

Funding: National Science Foundation (RAPID); USFS Geospatial Technology and Applications Center (GTAC)

Collaborators: Monica G. Turner (University of Wisconsin); Craig Baker (USFS-GTAC)