Divergent growth and responses of conifer and broad-leaved trees to warming-drying climate in a semi-arid region, northern China

Forests provide irreplaceable ecosystem services for human society and prevent environmental degradation but climate change has substantially undermined these fundamental functions. It is therefore important to examine the responses and adaptation of different tree species to climate warming. Here, we investigated how climate warming has affected tree growth patterns and growth-climate responses of a conifer (Pinus tabuliformis) and two broad-leaved species (Populus davidiana and Betula platyphylla) in a temperate semi-arid region in the northern China. Our results showed that P. tabuliformis had a similar regional growth pattern and two broad-leaved species shared an interspecific growth similarity at the same site. Broad-leaved trees had a higher recovery and resilience to drought than the conifer while conifers were more resistant to drought compared to broad-leaved trees, indicating a faster drought-response of broad-leaved species than that of conifers. The warming climate has hindered the tree growth by exacerbating water-deficit, and in particular, water availability has become the limiting factor for the growth of pines in the area. Trees coped with the water-deficit by taking advantage of non-growing season water to compensate the water source for tree growth. The study not only revealed the differences of growth-climate responses between species but also highlighted the necessity to consider species-specific adaptation to climate warming and diversify forest management strategies.