Drought-induced forest mortality is associated with climatic factors (e.g., high-temperature, precipitation deficit) and forest age, but may vary due to difference in tree species. However, the large-scale investigation on forest mortality usually cannot specify the causes of death of different tree species.

Forests in Northeast China is of great importance for China's ecologically sustainable development. It is necessary to quantify the impacts of forest age and climate change on drought-induced forest mortality in Northeast China.

MA Tianxiao, Associate Researcher of the Landscape Process Research Team of the Institute of Applied Ecology, Chinese Academy of Sciences, recently completed a research quantifying drought-induced mortality rates of Northeast China's forests at tree species and regional scales through statistical fitting the relationship between Rainfall Use Efficiency (RUE) and precipitation, the relationship between drought-induced forest mortality and forest age, and the relationship between RUE and drought index (more specifically, the Standardized Precipitation Evapotranspiration Index, SPEI) in Northeast China.

Dr. MA and his colleagues used data from 2000 to 2020 and found that the annual drought-induced forest mortality rate in Northeast China was 0.49% in the 20 years, with relative high mortality rate occurred in young and old-growth forests, and the mortality rate was relatively high in areas dominated by shade-tolerant tree species. The researchers also revealed that abnormal high-temperature was the main driver of tree deaths that caused by climate extremes.

This study clarifies the impacts of high-temperature and precipitation deficit on forest mortality, which are of great significance for the quantitative analysis and prediction of tree death dynamics in climate change scenarios.

This study, funded by the National Key Research and Development Program of China and the National Natural Science Foundation of China, has been published in Agricultural and Forest Meteorology entitled "Age-related patterns and climatic driving factors of drought-induced forest mortality in Northeast China".