Ancestral practices reduce forest fire risk

A study in the US unveils the potential of traditional methods of indigenous peoples: selective harvesting and thinning can prevent fires while reducing emissions

by Matteo Cavallito

 

Physical harvesting of dead wood, combined with sustainable forestry practices such as thinning, would limit fire risk while proving, moreover, to be an effective alternative to residual combustion. Such a strategy, which is based on traditional methods in use in America for many centuries, also helps to lower CO2 emissions. This is supported by a new study conducted by Florida Atlantic University (FAU) in western U.S. forests and published in the Journal of Environmental Management.

The authors, in particular, noted how this approach promotes forest health, improves air quality and contributes to the fight against climate change by improving the ability of forests to store carbon.

Current practices pose significant risks

Over time, the authors recall, systematic suppression of natural fires, combined with drought and global warming, has resulted in an abnormal accumulation of dry branches, needles and leaves, fueling increasingly destructive fires. Methods currently used to reduce this combustible material include controlled burning, thinning, and pile burning.

Today, however, their effectiveness not only in preventing fires but also in restoring ecosystem functions – including carbon sequestration – “is increasingly questioned in the context of global warming and wildland-urban interface enhancements of extreme fire risk.”

Indeed, controlled fires pose significant risks. First, they can get out of control, plus they can worsen air quality and cause respiratory problems and economic losses. At the same time, then, the degradation of forests by burning and logging reduces their ability to absorb carbon. So what to do? One answer, researchers argue, would be provided today by restoring traditional practices.

 

Fewer fires and lower emissions

In fact, the study examined some ancestral methods of indigenous peoples who, for centuries, have managed forests with low-impact interventions and selective harvesting of materials. With this in mind, the authors simulated eight forest management scenarios in Sierra Nevada forests in the U.S., evaluating the impact of these strategies that include thinning, controlled burning and physical removal of plant residues. The results show that the combination of deadwood harvesting and thinning significantly reduces the risks of severe fires, such as those that reach tree crowns.

It also lowers carbon emissions and allows the material to be recovered in the form of biochar. That is a plant-based charcoal useful for storing the element and improving soil quality.

“Forest management alternatives involving a combination of fuel reduction treatments such as thinning, physical harvesting, and Rx burning (ThPyRx) and thinning and physical harvesting (ThPy),” the study states, “were effective in terms of; a) lowered probability of torching; b) reduced wildfire risk levels; c) lowered tree crowning percentage and crown fire potential; and d) minimum tree basal area killed.” The harvest-thinning combination, in particular, “resulted in the greatest carbon sequestration prospects via biochar conversion and innovative wood use.”

Carbon sequestration capacity also grows

According to the authors, this strategy has the potential to generate carbon credits, thereby offering additional economic benefits. Although in the long run traditional burning practices may emit more CO2 than a single unmanaged fire, in fact, converting dead material into biochar allows for increased carbon sequestration capacity. Thus helping to mitigate health and environmental impacts.

In any case, the authors conclude, “longer-term research, both simulation modeling and field experiments, will be helpful for testing its efficacy temporally with repeated treatments and in multiple forest types, especially its potential in restoring historic wildfire regimes for healthy and resilient forests.”