Kyle S Hemes

Mapping where California’s forests are out-of-sync with climate

Warming climatic conditions over the last century have led to observable shifts in the spatial organization of dominant tree species in California’s Sierra Nevada. Little is known, however, about the extent to which these shifts have tracked the magnitude of climate change. Hill et al., 2023 maps Vegetation Climate Mismatch in the Sierra Nevada—areas where climate change has left trees in climatic conditions where they have not historically occurred. Different vegetation types support different wildfire regimes, ecosystems, and ecosystem services. Our maps will be useful for anticipating vegetation transitions and informing long-term wildfire and ecosystem management across the Sierra Nevada mountains of California.

Ecosystem impacts of wildfire smoke

Exacerbated by climate change, wildfire smoke is becoming a more common occurrence, especially across western North America. While we know that wildfire smoke has negative health impacts for humans, there is evidence that it could increase plant productivity. This occurs due to the way that smoke scatters incoming sunlight, allowing the sun's energy to reach further into dense plant canopies. We measured the impacts of wildfire smoke on vegetation productivity across a range of vegetation types, all with different canopy structures and physiological function, during the summer of 2018, an especially smoky year in the agriculturally productive Central Valley. We found that smoky conditions increased the efficiency by which the plant canopies photosynthesized, leading to productivity increases, depending on tradeoffs with total light and other pollutants. (See publications for link and news coverage.)