Landscape restoration minimizes tree growth vulnerability to 21st century drought in a dry forest

Abstract 

With hotter temperatures and less precipitation projected in the future, reducing tree density is a possible strategy to minimize the impacts of drought on forest growth. Many forest restoration programs are focused reducing tree density to minimize wildfire risks, but it is unknown how these efforts will impact drought vulnerability. In this study, we looked at how the Four Forest Restoration Initiative (4FRI) would alter landscape-scale patterns of forest growth and drought vulnerability throughout the 21st century. We found that hotter and drier conditions in the future could reduce tree growth, but the severity of drought and the magnitude of future growth declines was lessened by the thinning treatments. Compared to historical conditions, proportional tree growth by 2050 declines by ~40% if thinning continues at the status quo pace.  By comparison, proportional growth declines by only 20% if the 4FRI thinning treatments are fully implemented, and < 10% if stands are thinned even more intensively. These results indicate that forest restoration projects designed for other objectives can also have substantial benefits for minimizing future drought vulnerability in dry forests and provide additional incentive to accelerate the pace of restoration.

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Citation

Bradford, J.B., Andrews, C.M., Robles, M.D., McCauley, L.A., Woolley, T.J. and Marshall, R.M., 2021. Landscape‐scale restoration minimizes tree growth vulnerability to 21st century drought in a dry forest. Ecological Applications, 31(2), p.e2238. https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/eap.2238