Wetter summers mitigated temperature stress on western US forests during the last interglacial warm period.
Abstract
Rising summer temperatures are expected to increase mortality rates in forests across the western United States. Here, we use a unique collection of subfossil wood samples from the last interglacial warm period (80,000-130,000 years ago) to assess the ecological response of a western US forest to protracted warming. According to our downscaled model simulations, the region experienced a 2-4oC increase in canopy temperatures, ~30% increase in leaf-level evaporative demand and diminished spring snowpack during the interglacial yet, counterintuitively, the trees experienced enhanced growth rates and comparable water use efficiency relative to today. Isotopic analysis of the subfossil wood shows that increased utilization of summer rain compensated for the growth limitations imposed by warming. The results highlight how changes in summer rain in response to warming can not only modulate the magnitude of forest stress from warming but also change the direction of the response.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGC51L1077B
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSES;
- 1621 Cryospheric change;
- GLOBAL CHANGE;
- 1630 Impacts of global change;
- GLOBAL CHANGE;
- 1637 Regional climate change;
- GLOBAL CHANGE