How Hot is Too Hot?

Scientists are studying the upper thermal limit of trees in response to tree die-offs caused by extreme heatwaves. The 2021 "heat dome" in the Pacific Northwest, attributed to human-caused climate change, resulted in tree deaths. Climate change is increasing the duration, frequency, and intensity of heatwaves, posing a threat to trees and their ability to provide ecosystem services and sequester carbon. Scientists are trying to understand the damage caused by direct heat and sun exposure versus prolonged hot drought. A review of scientific literature found that the thermal tolerances of only 0.31% of land-based plants have been determined, which is concerning given the high confidence predictions for extremely hot temperatures due to climate change. Forests are already experiencing stress from hot drought conditions, and tree die-offs linked to climate change have been observed across various biomes. Limiting global warming is crucial, but extreme heat events can still have profound effects on forests. The loss of culturally important trees like the European beech is already being felt, leading to psychological and ecological instability. Large-scale forest mortality could significantly change the look and structure of forests for generations. The effects of climate change are already impacting individuals like Phil Hunter, a Christmas tree farmer who has seen tree deaths on his farm due to hot-drought conditions. Adapting to the changing climate is necessary to mitigate the effects of extreme heat on plants and ecosystems. [Extracted from the article]