Landscape-scale forest restoration decreases vulnerability to drought mortality under climate change in southwest USA ponderosa forest

Lisa A. McCauley, John. B. Bradford, Marcos D. Robles, Robert K. Shriver, Travis J. Woolley, Caitlin A. Andrews

Arizona

Climate Change, Fire, Forest Restoration Benefits

Forest

USGS

Abstract

Drought is projected to increase tree mortality in many western US forests due to climate change and could result in large-scale tree die-offs, altering forest composition and ecosystem services. Tree mortality has also been found to be higher in forests with greater tree density. Southwestern US forests are particularly susceptible to increased tree mortality due to the predicted temperature increases, drier soils, and forests with high tree density. The goal of this study was to examine how the Four Forests Restoration Initiative (4FRI), a large-scale forest restoration currently being implemented to reduce the risk of severe wildfire, will affect ponderosa pine mortality under climate change. We found that without thinning, mid-century changes in climate could increase annual ponderosa pine mortality rates by 45–57% over contemporary rates. However, with 4FRI thinning, mid-century mortality was predicted to remain near or below contemporary rates and these rates are 31–35% less than the mid-century scenarios without thinning. Our study shows that while climate change is likely to increase tree mortality rates, large-scale forest restoration projects, such as 4FRI, have the potential to ameliorate the effects of climate change and keep mortality rates near contemporary levels for decades.

Links

Explore Our Science

For publications and reports from our science team, please search here. However, to see the rest of our content, including many new science stories, please go to our new page here.

Explore Our Science

Jun 2025

Papers

Arizona

Forest

Forest Restoration Benefits

USFS

Evan Hjerpe and Anne Mottek Lucas, Conservation Economics Institute

Regional Economic Contributions of the Four Forests Restoration Initiative (4FRI) in Northern Arizona in 2023

A regional economic contribution analysis of the Four Forest Restoration Initiative (4FRI) was conducted for Calendar Year 2023, illustrating regional employment and output from 4FRI in five northern Arizona counties. Forest restoration in communities with high wildfire risk is done primarily throug[…]

Dec 2024

Maps

BLM, NGO

Freshwater Assessment

Riparian-aquatic

San Pedro River

Dale Turner, Brooke Bushman, Lisa McCauley, Patrick Hellmann

San Pedro River Wet/Dry Map Animation

Every June groups of volunteers walk the entire 170 mile length of the San Pedro River and record where it is wet and where it is dry during the hottest, driest time of the year. Twenty years’ worth of data on summertime surface flows in the San Pedro River within the San Pedro Riparian National C[…]

Dec 2024

Maps

BLM, NGO

Freshwater Assessment

Riparian-aquatic

San Pedro River

Turner, D., L. McCauley, P. Hellmann

San Pedro River Wet-Dry Maps

The San Pedro River wet/dry mapping dataset is a community effort to track the river’s health by monitoring the persistence of surface water during the driest time of each year. It is created by recording the end points of every wet section of the San Pedro River during June each year. Maps depict[…]