Shifts in tree functional composition amplify the response of forest biomass to climate

Shifts in tree functional composition amplify the response of forest biomass to climate

Nature 556, 7699 (2018). doi:10.1038/nature26152

Authors: Tao Zhang, Ülo Niinemets, Justin Sheffield & Jeremy W. Lichstein
Forests have a key role in global ecosystems, hosting much of the world’s terrestrial biodiversity and acting as a net sink for atmospheric carbon. These and other ecosystem services that are provided by forests may be sensitive to climate change as well as climate variability on shorter time scales (for example, annual to decadal). Previous studies have documented responses of forest ecosystems to climate change and climate variability, including drought-induced increases in tree mortality rates. However, relationships between forest biomass, tree species composition and climate variability have not been quantified across a large region using systematically sampled data. Here we use systematic forest inventories from the 1980s and 2000s across the eastern USA to show that forest biomass responds to decadal-scale changes in water deficit, and that this biomass response is amplified by concurrent changes in community-mean drought tolerance, a functionally important aspect of tree species composition. The amplification of the direct effects of water stress on biomass occurs because water stress tends to induce a shift in tree species composition towards species that are more tolerant to drought but are slower growing. These results demon...

Source: Nature - March 21, 2018 Category: Research Authors: Tao Zhang Ülo Niinemets Justin Sheffield Jeremy W. Lichstein Tags: Letter Source Type: research