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Woody debris and tree regeneration dynamics following severe wildfires in Arizona ponderosa pine forests

John Paul Roccaforte, Peter Z. Fulé, W. Walker Chancellor, Daniel C. Laughlin
Summary - what did the authors do and why?

The authors sampled post-fire surface fuels, woody debris and regeneration along a chronosequence of eighteen years within ponderosa pine stands that burned at high severity to understand how surface fuels change with time since fire.

Publication findings:

The authors found that snag density rapidly declined as time since fire increased as snags fell rapidly in the first few years post-fire and transitioned to other snag condition classes soon after. Course woody debris loading increased with time since fire and peaked between 6-12 years post-fire, but was still within recommended management values, until it turned into rotten wood at approximately 16 years post-fire. The authors also found that after severe fires, over half of the sites lacked any ponderosa pine regeneration and was more likely to be dominated by sprouting species, although one site did have hyperdense pine regeneration. The authors suggest that these sites may go decades as shrublands or grasslands, and it remains to be seen if they return to a forested state.

Fire and Ecosystem Effects Linkages

How does fire severity relate to tree dispersal, regeneration, and establishment?

The authors also found that after severe fires, over half of the sites lacked any ponderosa pine regeneration and was more likely to be dominated by sprouting species, although one site did have hyperdense pine regeneration. The authors suggest that these sites may go decades as shrublands or grasslands, and it remains to be seen if they return to a forested state.

How does fire severity relate to fuels?

The authors found that snag density rapidly declined as time since fire increased as snags fell rapidly in the first few years post-fire and transitioned to other snag condition classes soon after. Course woody debris loading increased with time since fire and peaked between 6-12 years post-fire, but was still within recommended management values, until it turned into rotten wood at approximately 16 years post-fire.

How does fire severity relate to species composition, non-natives, and structure?

The authors also found that after severe fires, over half of the sites lacked any ponderosa pine regeneration and was more likely to be dominated by sprouting species, although one site did have hyperdense pine regeneration. The authors suggest that these sites may go decades as shrublands or grasslands, and it remains to be seen if they return to a forested state.