Development of universal response functions for transfer of Cunninghamia lanceolata (Lamb.) Hook. in subtropical China

Reanalysis of historical provenance trial data yields critical knowledge that can enhance climate change adaptation. The universal response functions (URFs) were developed for 205 populations of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) growing at 32 planting sites in subtropical China. Tree growths were modeled for contemporary climate and then projected using data from three climate models for the periods 2011–2040, 2041–2070, and 2071–2100, under three scenarios of trajectories of greenhouse gas concentrations (SSP119, SSP245, SSP585). Mean coldest month temperature (MCMT) of provenance and test site explained 33.8–41.8 % of population variation in regressions that were statistically significant. However, growth performance was mainly related to MCMT at test site and, to a lesser degree, to MCMT at seed origin, indicating a pronounced environmental response of Chinese fir populations. There was a clear indication of a climatic optimum in central regions, and the growth of Chinese fir is expected to be limited at sites with the MCMT of more than approximately 8 °C under climate warming. The URFs’ explicit predictions indicated that populations from northern regions exhibited a moderate increase in growth, while for southern populations, a marked reduction in growth will be observed. Under severe global warming (SSP585), local populations at the southern margins might face extirpation. Assisted migration could help most populations take advantage of potential growth opportunities in warmer climates. As an important tree species in subtropical plantations, the lessons learnt from Chinese fir will help to avoid potential maladaptation of forests to future climates.