[Characteristics of dominant tree species stem sap flow and their relationships with environmental factors in a mixed conifer-broadleaf forest in Dinghushan, Guangdong Province of South China].
By the method of Granier' s thermal dissipation probe, the stem sap flow density of four dominant tree species (Pinus massoniana, Castanopsis chinensis, Schima superba, and Machilus kwangtungensis) in a mixed conifer-broadleaf forest in Dinghushan Reserve of South China was continuously measured in the dry season (November) and wet season (July) in 2010, and the environmental factors including air temperature, relative humidity, and photosynthetically active radiation (PAR) were measured synchronically, aimed to study the characteristics of the stem sap flow of the tree species in response to environmental factors. During the dry and wet seasons, the diurnal changes of the stem sap flow velocity of the tree species all presented a typical single-peak curve, with high values in the daytime and low values in the nighttime. The average and maximum sap flow velocities and the daily sap flow flux of broad-leaved trees (C. chinensis, S. superba, and M. kwangtungensis) were significantly higher than those of coniferous tree (P. massoniana), and the maximum sap flow velocity of P. massoniana, C. valueschinensis, S. superba, and M. kwangtungensis was 29.48, 38.54, 51.67 and 58.32 g H2O x m(-2) x s(-1), respectively. A time lag was observed between the sap flow velocity and the diurnal variations of PAR, vapor pressure deficiency, and air temperature, and there existed significant positive correlations between the sap flow velocity and the three environmental factors. The PAR in wet season and the air temperature in dry season were the leading factors affecting the stem sap flow velocity of the dominant tree species.
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China. huangdw@scbg.ac.cn
De-Wei
DW
Huang
De-Qiang
DQ
Zhang
Guo-Yi
GY
Zhou
Shi-Zhong
SZ
Liu
Dennis
D
Otieno
Yue-Lin
YL
Li
D002623:Chemistry Techniques, Analytical / Q000295:instrumentation; D002681:China; D017753:Ecosystem; D004777:Environment; D010788:Photosynthesis / Q000502:physiology; D028223:Pinus / Q000378:metabolism / Q000502:physiology; D018547:Plant Stems / Q000378:metabolism / Q000502:physiology*; D018526:Plant Transpiration / Q000502:physiology; D064028:Tracheophyta / Q000378:metabolism / Q000502:physiology; D014197:Trees / Q000378:metabolism / Q000502:physiology*; D014867:Water / Q000378:metabolism*
D014867:Water