Event Title

Factors Associated With Crown Damage Following Recurring Mixed-Severity Wildfires and Post-Fire Management

Event Website

http://www.nafew2009.org/

Start Date

24-6-2009 10:30 AM

End Date

24-6-2009 10:50 AM

Description

Wildfires and post-fire management have a lasting influence on live and dead vegetation, which can, in turn, affect the behavior of future fires. Recent large wildfires in 1987 (Silver) and 2002 (Biscuit) provided an opportunity to examine how mixed-severity fires burn under moderate and extreme weather conditions. The fires also provided a chance to examine how forest management and overlapping fires affect severity patterns. We characterize crown damage patterns using multi-date digital aerial photography. The Biscuit Fire re-burned 38,000 hectares of mixed-conifer/evergreen hardwood forest that had burned heterogeneously during the Silver Fire and then was subject, in part, to post-fire logging and planting. Median Biscuit Fire crown damage within the re-burn, including damage to the shrub-stratum, was 63% in unmanaged areas, and was strongly related to damage in the Silver Fire. Areas that burned severely in the Silver Fire succeeded to a mix of shrubs and tree regeneration, which then experienced high levels of Biscuit Fire damage. In contrast, tree-stratum damage in the Biscuit Fire was largely independent of Silver Fire damage. Median tree crown damage was 39% for conifer cover and 85% for hardwood cover, and was most strongly related to average daily temperature and “burn period,” an index of fire weather fire and fire suppression effort. Areas that burned severely in the Silver Fire, and then were salvage logged and planted with conifers had median Biscuit Fire damage of 100%. Areas that burned severely but were not managed had median crown damage of 95%. The managed areas were at higher topographical positions and had greater pre-fire cover. Our findings suggest that in productive, fire-prone landscapes, the post-fire mosaic of vegetation structure can influence the severity pattern of future wildfires and that post-fire salvage logging and planting does not reduce future fire severity, at least in the short term.

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Jun 24th, 10:30 AM Jun 24th, 10:50 AM

Factors Associated With Crown Damage Following Recurring Mixed-Severity Wildfires and Post-Fire Management

Wildfires and post-fire management have a lasting influence on live and dead vegetation, which can, in turn, affect the behavior of future fires. Recent large wildfires in 1987 (Silver) and 2002 (Biscuit) provided an opportunity to examine how mixed-severity fires burn under moderate and extreme weather conditions. The fires also provided a chance to examine how forest management and overlapping fires affect severity patterns. We characterize crown damage patterns using multi-date digital aerial photography. The Biscuit Fire re-burned 38,000 hectares of mixed-conifer/evergreen hardwood forest that had burned heterogeneously during the Silver Fire and then was subject, in part, to post-fire logging and planting. Median Biscuit Fire crown damage within the re-burn, including damage to the shrub-stratum, was 63% in unmanaged areas, and was strongly related to damage in the Silver Fire. Areas that burned severely in the Silver Fire succeeded to a mix of shrubs and tree regeneration, which then experienced high levels of Biscuit Fire damage. In contrast, tree-stratum damage in the Biscuit Fire was largely independent of Silver Fire damage. Median tree crown damage was 39% for conifer cover and 85% for hardwood cover, and was most strongly related to average daily temperature and “burn period,” an index of fire weather fire and fire suppression effort. Areas that burned severely in the Silver Fire, and then were salvage logged and planted with conifers had median Biscuit Fire damage of 100%. Areas that burned severely but were not managed had median crown damage of 95%. The managed areas were at higher topographical positions and had greater pre-fire cover. Our findings suggest that in productive, fire-prone landscapes, the post-fire mosaic of vegetation structure can influence the severity pattern of future wildfires and that post-fire salvage logging and planting does not reduce future fire severity, at least in the short term.

http://digitalcommons.usu.edu/nafecology/sessions/mixed_fire/2