Theme: East-West Interdisciplinary Boreal Forest Fire Experiment, Part 4 Moderator: V.V. Furyaev and Eino Mälkönen 10.8.1995 9:30 Room: U16
Post-Fire Tree Mortality and Insect Infestation in Pinus sylvestris on Bor Forest Island, Krasnoyarsk Region, Siberia
Conard, Susan G., Ivanova, Gallina A., Furyaev, Valentin V., Regelbrugge, Jon C.
We investigated tree mortality and bark beetle infestation following an experimental fire in the Krasnoyarsk Region of Siberia in July 1993. The fire was conducted in a stand of nearly pure Pinus sylvestris forest on a 55 ha island surrounded by Sphagnum bog. Because the major purpose of the fire was to evaluate smoke emissions and other impacts of a stand-replacement fire, the fire was ignited in such a way that approximately 57 % of the island burned in a crown fire. All of the trees in these parts of the stand died. In another 25 % of the area, the surface fire was severe enough to scorch the majority of tree crowns. Most trees in these areas also were dead by a year later.
Immediately after the fire, we measured fire injury and tree characteristics on 100 trees distributed across the range of fire severity. In July of 1994, we assessed mortality of those trees and added another 100 trees to the sample, with the objective of increasing sample size and obtaining more sample trees in less severely burned areas of the island. Our objective was to develop logistic regression models of tree mortality based on observable fire severity parameters, including canopy scorch (1993 only) and maximum and minimum char height on the bole, and on tree characteristics such as diameter, height, and length of crown. This study is part of a larger effort to develop regional models relating P. sylvestris mortality following fires to simple fire severity measures.
Of the 201 trees sampled, 57 percent were dead by a year after the fire. We have developed preliminary models of tree mortality, in which tree diameter and stem char height (relativized to tree height) are the predictor variables. All dead trees sampled, as well as 85 percent of the living trees, were infested with bark beetles. Although most of the living trees had relatively low levels of infestation, another year will be required to evaluate whether these trees will survive the combined effects of the insects and the fire.
Key words: Pinus sylvestris, stand-replacement fire, post-fire mortality, fire effects.
Correspondence: Susan G. Conard, Forest Service, US Department of Agriculture, Pacific Southwest Research Station, Forest Fire Laboratory, 4955 Canyon Crest Drive, USA-Riverside, California 92507