Carbon Flux Variation Characteristics and Carbon Sequestration Analysis of Deciduous Broadleaf Forest in a Coastal City

ZHAO Ruonan; ZHEN Xiaoju; ZHANG Mi; WANG Sha; WU Ming; ZHAO Jiayu; GE Pei; BAO Hengxin

doi:10.19672/j.cnki.1003-6504.0659.23.338

Abstract：Forest ecosystems,as the largest carbon reservoirs in terrestrial ecosystems,play an important role in regulation of atmospheric CO2.Qinhuangdao is an ecologically livable tourist city,and the long-term continuous monitoring of CO2 flux in the forest ecosystem helps the city's carbon accounting.The CO2 flux of forest ecosystem in Qinhuangdao,Hebei Province was continuously observed by eddy covariance method,the characteristics of carbon sources and sinks at the monthly scale were clarified,and the carbon budget including ecosystem respiration,net ecosystem productivity,and gross primary produc-tivity were quantified,as well as water use efficiency.The results shows that during the growing season,it possessed a certain carbon sink function,acting as a weak carbon sink with a carbon sequestration of 88.14 g/m2.Carbon sink in May,June and August,with maximum value of-74.19 g/m2 in May and minimum value of-22.45 g/m2 in August,and weak carbon source in July,and carbon source in September,with the value of 4.29 and 58.83 g/m2,respectively.Net ecosystem productivity was 88.14 g/m2 with a relatively low level of productivity in temperate forest ecosystems;the respiration was 1 400.44 g/m2;the gross primary productivity was 1 488.58 g/m2;and the water use efficiency was 3.41 g/kg H2O with a relatively high level.Net ecosystem productivity was associated with radiation conditions.No considering the data of September,the total primary productivity was related to air temperature and saturated water vapor pressure difference.The water use efficiency was not significantly related to radiation conditions,saturated water vapor pressure difference,air temperature.