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Study: Replanting Trees After Wildfires May Not Be Necessary

November 9, 2018

New research is offering a way to potentially save money and resources on forest recovery after wildfire.

After wildfire season ends each year, land managers start planning what comes next for the areas that burned.  Often, the strategy used to ensure the forests return is to salvage log and then replant. But a recent study suggests that in some areas, it might be just as effective to leave the forest alone.

“If the burned patches aren’t too big, that is to say the seed sources aren’t too far away, then the forests do a good job of regenerating themselves,” said study contributor David Hibbs of Oregon State University.

The research provides a relatively clear picture of where forest managers could most benefit from spending the time and money needed to replant — at least in corner of the Pacific Northwest. 

Hibbs says the results should be interpreted relatively narrowly, based on the forest type, elevation, tree species and the direction of the slope where the trees grow.

Researchers looked at tree growth in the Klamath-Siskiyou forests of southern Oregon and northern California.  They examined more than 60 sites that had burned 20 years previously. Some of the sites were replanted after wildfire and others weren’t touched. 

“Basically, if you do nothing – no human intervention at all – you get really high conifer regeneration by those Douglas Fir.  So the unmanaged and managed sites were indistinguishable for conifer regeneration,” said Portland State University’s Melissa Lucash, a co-author of the paper.

The results were more mixed for ponderosa pine.  In certain hotter and drier areas, replanting produced higher numbers of these drought-tolerant trees than natural regrowth.

Researchers say carefully targeting tree replanting projects to where they’re needed most could free up resources for projects to reduce high-severity wildfire in the first place.

The research was published in the journal Forest Ecology and Management.  


The Miller Complex Fire burned in Southern Oregon and Northern California in 2017. The fire killed some trees, but also left many trees alive.

Cassandra Profita/OPB