Abstract: Tree biomass and its allocation characteristics is an important indicator for studying the impact of global warming on forest ecosystems. It not only reflects tree growth under the background of global warming, but also reveals the carbon cycle and carbon allocation dynamics of forest ecosystems. The response of tree biomass and allocation characteristics to global warming is one of the hot and challenging topics in global change research. At present, some studies reported that warming would significantly increase tree biomass, change plant phenology, prolong the growing season, and increase the biomass in high latitude and altitude areas. In contrast, other studies found that warming has no significant effect on tree biomass. In addition, some studies reported that warming will increase belowground biomass by reducing the allocation of aboveground biomass. However, how forest tree biomass and allocation respond to climate warming and the underlying mechanisms have not been fully understood. Here, we systematically expound the research progress of changes in forest tree biomass and allocation characteristics under the background of global warming, aiming to provide reference for indepth research on changes in forest tree biomass and on the response and adaptation mechanism of forests to global change. The following aspects should be strengthened in the future: (1) Examining the effects of climate warming on forest tree biomass and its allocation characteristics with various warming treatments; (2) The effects of changes in tree phenological patterns or growth rates on forest tree biomass; (3) The biomass and allocation characteristics of forest trees under the combined effects of warming and other environmental factors; (4) Improving the accuracy of research by combining model simulation, indoor simulation experiment and field insitu warming experiment.

Key words: global warming, forest ecosystem, biomass allocation, root-shoot ratio, influencing mechanism