Study: Forest Thinning Boosts Ponderosa Pine Seedlings

May 20, 2016

Ponderosa pine seedlings are more likely to sprout and thrive in mechanically thinned forests, a new study out of Flagstaff finds.

Ponderosa pine seedlings that sprouted in 2013.
Credit Melissa Sevigny


The study began in 2013 when researchers counted ponderosa seedlings in 18 experimental forest plots. They monitored seedling survival for two years in both densely treed and mechanically thinned areas.

Tom Kolb of Northern Arizona University coauthored the study. He says, “What we found was that in the medium density plots—the plots that had had moderate to heavy thinning over the last 50 years—that survival was surprisingly high.”

That’s partly because trees in thinned plots produced more pinecones and thus more seedlings. Also, young trees in those areas received more light and nutrients.

Kolb says the results suggest mechanical thinning could help counter the effects of climate change on ponderosa pine forests.