The research will be published Friday in Sciencexpress and later presented in the journal Science, by scientists from Oregon State University and the Institute of Pacific Islands Forestry in Hawaii. It provides some of the first actual data about forest regeneration in this vast, burned area.
Even following a high severity fire such as this, which covered more than 450,000 acres and was the largest in Oregon history, the natural conifer regeneration on study sites was about 300 seedlings per acre, and 80 percent Douglas fir. However, logging reduced the regeneration by 71 percent, and would necessitate manual planting to restore seedling levels that otherwise would have occurred naturally.
In addition, the study suggested that logging, by itself, would actually increase the levels of material that could fuel another fire in the near future, because of the "pulse" of easily-burned fine fuels and waste wood left behind on the forest floor after trees are felled and processed. Other fuel reduction approaches besides logging would still be needed, the researchers said, with additional expense.
"Surprisingly, it appears that after even the most severe fires, the forest is naturally very resilient, more than it's often given credit for," said Dan Donato, a graduate student in the Department of Forest Science at OSU and lead author on the study.
"And if another of our goals is to reduce the risk of early re-burn, the best strategy may be to leave dead trees standing," he said.
"In the absence of post-fire logging, we would expect the fuels to fall to the ground over some protracted period, as opposed to the single pulse of high fire risk we saw after logging
Contact: Dan Donato
Oregon State University