Measurement of leaf area index of three plantations and their seasonal changes in Heshan hilly land
Leaf area index ( LAI) is an important parameter in forest canopy structure. Measurement values of optical instrument often underestimate LAI and need to be corrected. Effective leaf area index ( LAIe ) measured by a CI-110 digital plant canopy imager (DPCI) was calibrated by LAI in three plantations of Acacia mangium plantation, Schima plantation ( S. superba + S. wallwhi ) and coniferous plantation ( Pinus massoniana + Cunninghamia lanceolata) in Heshan hilly land, Guangdong Province, South China. Direct determination was used to estimate LAI of three plantations, and the seasonal changes of LAI were analyzed as well. Direct estimations were higher than optical estimations, and significant correlations (P < 0.01) were found between LAI and LAIe for each plantation with different equations. There weren t obvious seasonal changes of LAI in three plantations as a whole. Schima plantation had the highest mean annual LAI (6.56) among the plantations,followed by A. mangium plantation (3.94) and coniferous plantation (3.76),and LAI of Schima plantation was obviously higher than those of A . mangium and coniferous plantations ( P < 0.05) . Compared with historical data, the results suggest that LAIs of Schima ,coniferous and A . mangium plantations present the definite trend of increase, relative stabilization and decrease, respectively.
leaf area index ( LAI)specific leaf area ( SLA )CI-110 digital plant canopy imagerplantation