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- Info
Fuels management reduces tree mortality following wildfire
| Author: |
Outcalt, Kenneth W.; Wade, Dale D. |
| Date: |
[2000] |
| Periodical: |
[publication informantion unknown]. 15 p |
| Link: |
http://flame.fl-dof.com/joint_fire_sciences/dem007.html
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| Abstract: |
The objective of this study was to test the effectiveness of a regular prescribed burning program for reducing mortality of southern pines when forests are burned by wildfire. This study was conducted on the USDA Forest Service Osceola National Forest, the Florida Division of Forestry Tiger Bay State Forest, and Georgia Pacific Lake Butler Forest. The major portion of the study was installed on the Osceola National Forest where about 10,000 ha of flatwoods forest type was burned by arson-set wildfires under extreme conditions in June 1998. Tree mortality data, summarized by plot, were compared using analyses of variance in an unbalanced design to test for differences in pre-fire fuel treatments, site type, location and fire type. Mean mortality was 41 percent in natural stands and 34 percent in plantations two growing seasons after the wildfire. Burn history significantly affected mortality with those stands prescribed burned 1.5 years before the wildfire having the lowest mortality, while stands prescribed burned 2 years or more before the wildfire had much higher mortality. Site type significantly influenced tree mortality in natural stands. On dry and moist sites, 30% of the pines died whereas the wildfire killed 65% of the trees on normally wet plots. Crown loss, but not bole char was very good at predicting delayed tree mortality. Pines with greater than 70% crown loss were nearly certain to die. There was also a selective removal of the smaller trees from stands. Although significant tree mortality did occur on the Osceola National Forest with all trees killed in some stands, many trees in other burned stands did survive. The overall mortality was much lower in both plantations and natural stands on the Osceola than was found at Tiger Bay where prescribed burning had been much less frequent. The highest mortality rates occurred on the Lake Butler Forest where prescribed burning had not been used since plantation establishment. Thus, we conclude that a regular prescribed burning program will reduce mortality following wildfires in both natural and planted stands of southern pines on flatwoods sites, even under severe drought conditions. |
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