Final Report: Informing and Evaluating Forest Management Strategies to Promote Drought Resistance
Dates
Publication Date
2018-02-23
Citation
John Bradford, 2018, Forest Management Strategies to Promote Drought Resistance and Resilience.
Summary
Severe droughts cause widespread tree mortality and decreased growth in forests across the globe. Forest managers are seeking strategies to increase forest resistance (minimizing negative impacts during the drought) and resilience (maximizing recovery rates following drought). Limited experimental evidence suggests that forests with particular structural characteristics have greater capacity to resist change and or recover ecosystem function in the face of drought. However, the applicability of these results to practical forest conservation and management remains unclear. This project utilized an existing network of eight long-term, operational-scale, forest management experiments from Arizona to Maine to examine how established forest [...]
Summary
Severe droughts cause widespread tree mortality and decreased growth in forests across the globe. Forest managers are seeking strategies to increase forest resistance (minimizing negative impacts during the drought) and resilience (maximizing recovery rates following drought). Limited experimental evidence suggests that forests with particular structural characteristics have greater capacity to resist change and or recover ecosystem function in the face of drought. However, the applicability of these results to practical forest conservation and management remains unclear. This project utilized an existing network of eight long-term, operational-scale, forest management experiments from Arizona to Maine to examine how established forest management prescriptions that include thinning can increase resistance and resilience of forest habitats to drought. We found that drought inhibits forest growth in all climates we examined, including the relatively cool and dry forests of the U.S. northeast. We also found that growth declines during drought are more severe when the density of trees is greater, and the negative impact of density was, surprisingly, greatest in wetter climates. Our analysis indicates that snowpack is especially important for supporting tree growth in warmer, drier areas, and can inhibit tree growth in cold climates. Examination of drought conditions under future climate conditions indicates soils are likely to be drier during the spring and summer months, which are especially important for supporting tree growth. Our results suggest that removing some trees from forests can reduce the competition for water and help trees decrease stress imposed by increasingly dry conditions.
