Responses of canopy stomatal conductance of Acacia mangium forest to environmental driving factors
Zhao, P.; Rao, X.; Ma, L.; Cai, X'an.; Zeng, X.
Ying Yong Sheng Tai Xue Bao 17(7): 1149-1156
2006
ISSN/ISBN: 1001-9332 PMID: 17044483 Document Number: 603815
Responses of canopy stomatal conductance of Acacia mangium forest to environmental driving factors. ZHAO Ping, RAO Xingquan, MA Ling, CAI Xi' an, ZENG Xiaoping (South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China). -Chin. J. Appl. Ecol. 2006,17 (7) : 1149 similar to 1156. Employing Granier probes, this paper measured the sap flow of 14 sample trees in an Acacia mangium forest on the Heshan hilly lands of Guangdong Province, and recorded the photosynthetic active radiation (PAR), air relative humidity ( RH ), and air temperature ( T ) above the forest canopy. The whole-tree transpiration ( E ), stand transpiration ( E-1 ), and mean canopy stomatal conductance ( g(c) ) were calculated, and the relationships between tree morphological characters and whole-tree water use as well as the responses of g. to PAR and vapor pressure deficit (D) were analyzed. The results showed that the whole-tree transpiration had logarithmical positive cor-relations with tree diameter at breast height ( DBH ) ( P < 0.0001 ), sapwood area ( P < 0.0001 ) and canopy size ( P =0.0007 ), and an exponential positive correlation with tree height ( P = 0.014 ). The maximum g(c) (g(c) (max)) changed with PAR hyperbolically ( P < 0.0001 ), and with D logarithmically ( P < 0.0001 ). The sap flow measurement system used in this study was reliable and accurate in estimating the transpiration of whole-tree and stand and the canopy stomatal conductance, being an effective tool in studying the relationships between forest water use and environmental factors.