Event Title

Contributions of Fire-Killed Trees to Future Wildlife Habitat and Surface Fuels in Dry Coniferous Forests

Event Website

http://www.nafew2009.org/

Start Date

22-6-2009 10:50 AM

End Date

22-6-2009 11:10 AM

Description

Fire-killed trees provide critical habitat for many species, but also add to surface fuels as they decay and fall. Recent debates over post-fire logging practices and their impacts have highlighted the need for a greater understanding of trade-offs between use of fire-killed trees by cavity-nesting birds and fuel succession patterns after high severity wildfires. For this study, we surveyed fire-killed trees and measured surface fuels on 126 plots within a chronosequence of 49 wildfires that burned dry coniferous forests of eastern Washington and Oregon during 1970-2007. We recorded diameter, species, and the presence or absence of cavities for each tree sampled. Fuels were measured with three fuel transects per plot. Analysis with mixed regression models showed small fuels (1-hour to 100-hour) were highly variable and not strongly related to time since fire or most measured stand-level variables. In contrast, 1000-hour fuels accumulated over time, especially in stands where tree density and basal area were high at the time of the fire. Snags with broken tops were more likely to have cavities than whole snags, and ponderosa pine snags were somewhat more likely to have cavities than Douglas-fir snags. The probability of snag usage by cavity nesters increased over time, but varied among snag diameter size classes. Small snags (15 to 30 cm diameter at breast height) were very unlikely to have a cavity at any time. Moderate size snags (30 to 60 cm diameter) had the greatest increase in odds of a cavity with time since fire up to 30 years. These results suggest that removing smaller trees after fire, especially in dense stands, may help reduce fuels with few impacts on cavity nesters, but retention of some moderate size trees may be necessary to maintain habitat continuity in the first few decades following wildfire.

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Jun 22nd, 10:50 AM Jun 22nd, 11:10 AM

Contributions of Fire-Killed Trees to Future Wildlife Habitat and Surface Fuels in Dry Coniferous Forests

Fire-killed trees provide critical habitat for many species, but also add to surface fuels as they decay and fall. Recent debates over post-fire logging practices and their impacts have highlighted the need for a greater understanding of trade-offs between use of fire-killed trees by cavity-nesting birds and fuel succession patterns after high severity wildfires. For this study, we surveyed fire-killed trees and measured surface fuels on 126 plots within a chronosequence of 49 wildfires that burned dry coniferous forests of eastern Washington and Oregon during 1970-2007. We recorded diameter, species, and the presence or absence of cavities for each tree sampled. Fuels were measured with three fuel transects per plot. Analysis with mixed regression models showed small fuels (1-hour to 100-hour) were highly variable and not strongly related to time since fire or most measured stand-level variables. In contrast, 1000-hour fuels accumulated over time, especially in stands where tree density and basal area were high at the time of the fire. Snags with broken tops were more likely to have cavities than whole snags, and ponderosa pine snags were somewhat more likely to have cavities than Douglas-fir snags. The probability of snag usage by cavity nesters increased over time, but varied among snag diameter size classes. Small snags (15 to 30 cm diameter at breast height) were very unlikely to have a cavity at any time. Moderate size snags (30 to 60 cm diameter) had the greatest increase in odds of a cavity with time since fire up to 30 years. These results suggest that removing smaller trees after fire, especially in dense stands, may help reduce fuels with few impacts on cavity nesters, but retention of some moderate size trees may be necessary to maintain habitat continuity in the first few decades following wildfire.

http://digitalcommons.usu.edu/nafecology/sessions/fire_effects/5