Drought Impact on Carbon Assimilation of A Zelkova Serrata Plantation

Abstract

Background: As anthropogenic greenhouse gas emissions intensify global climate change, plantations have become an important tool to mitigate atmospheric CO2. Our aim in this study was to estimate carbon assimilation and clarify the impact of environmental factors on the photosynthesis of Zelkova serrata, an important plantation species, which extensively planted in low altitude of East Asia.Results: We measured monthly gas exchange parameters and leaf area to estimate carbon assimilation. The results showed that gas exchange was significantly affected by vapor pressure deficit and temperature, especially in the dry season, and both photosynthetic rate and carbon assimilation decreased. However, drought led to lower daytime assimilation and higher night-time respiration, which caused a 43% decrease in carbon assimilation. Additionally, the poor site quality and environmental stress may impact the growth and carbon assimilation of this species.Conclusions: Z. serrata may not be suitable for planting in a tropical monsoon climate area. Therefore, the effects of extreme weather on the forest carbon budget may be stronger in the future. Leaf area showed seasonal variation and serious defoliation caused by a typhoon in the summer. The monthly leaf assimilation rate was 0.88–4.17 μmol CO2 m-2 s-1, which was estimated to assimilate 3.50 Mg C ha-1 yr-1 in the study area.