A study reports a decrease in the time taken by forest vegetation to absorb and re-emit carbon, impeding forests' ability to store carbon. Forests serve as an important carbon sink, storing a quarter of anthropogenic carbon emissions annually. As a key player in the carbon cycle, forests have the potential to affect atmospheric carbon dioxide concentrations. Kailiang Yu and colleagues investigated carbon turnover rate, or the time it takes for carbon to be absorbed by forests before it is released back to the atmosphere. The authors analyzed long-term data, collected from 1955 to 2018, from 695 forest plots. The data represented mature, undisturbed forests in cold, temperate, and tropical climates of Europe and North and South America. Analysis revealed increased carbon loss and decreased carbon turnover time due to increased tree mortality. The turnover time was not correlated with the forests' successional stage or age. The authors note that ongoing climate changes are likely to affect plant growth and mortality rates of forests. To more accurately predict the ability of forests to act as carbon sinks, Earth systems models, which couple the carbon cycle with climate variation, should better account for tree mortality, according to the authors.
Article #18-21387: "Pervasive decreases in living vegetation carbon turnover time across forest climate zones," by Kailiang Yu et al.