Thursday, August 9, 2007
Exhibit Halls 1 and 2, San Jose McEnery Convention Center
Abstract
The net primary productivity (NPP) and Construction Cost in three pioneer communities (Acacia mangium, Schima and coniferous forests) in low subtropical hilly-land region (Heshan, Guangdong, China) were studied. The results showed that A. mangium forest had the highest biomass (176.03 t hm-2) among the three communities, followed by Schima (122.91) and coniferous (104.93) forests. Tree layers of the three communities accounted for the greatest proportion of the total biomass (95.1~98.7%), while shrub and herb layers formed only a small part of the total biomass (0.9~4.5% and ~0.4%, respectively). The NPP (t hm-2 yr-1) of A. mangium forest was 25.31, which was 29.2% and 37.6% higher than Schima and coniferous forests, respectively. The canopy leaf area index (LAI) of Schima forest was obviously higher than those of A. mangium and coniferous forests, and higher LAI suggests that Schima forest has a more complex canopy structure. The highest mass-based construction costs (CC, in kg glucose kg-1)were observed in leaves while the lowest CC in roots for all the 20 species plants studied. CC of tree species was higher than that of shrub and herb plants in the three forest communities. CC of the coniferous tree species was evidently higher than that of broadleaf tree species for either mass-based or area-based calculation. Based on area-based calculation, the total CC (t glucose hm-2) of canopy leaves was 17.1 for coniferous forest, 7.8 for Schima forest and 5.8 for A. mangium plantation, i.e., the CC of coniferous plantation was significantly greater than that of the other two broadleaf forest. Coniferous plantation had lower resource use efficiency, i.e., it needs expend more energy to construct the carbon skeleton of plants.
The net primary productivity (NPP) and Construction Cost in three pioneer communities (Acacia mangium, Schima and coniferous forests) in low subtropical hilly-land region (Heshan, Guangdong, China) were studied. The results showed that A. mangium forest had the highest biomass (176.03 t hm-2) among the three communities, followed by Schima (122.91) and coniferous (104.93) forests. Tree layers of the three communities accounted for the greatest proportion of the total biomass (95.1~98.7%), while shrub and herb layers formed only a small part of the total biomass (0.9~4.5% and ~0.4%, respectively). The NPP (t hm-2 yr-1) of A. mangium forest was 25.31, which was 29.2% and 37.6% higher than Schima and coniferous forests, respectively. The canopy leaf area index (LAI) of Schima forest was obviously higher than those of A. mangium and coniferous forests, and higher LAI suggests that Schima forest has a more complex canopy structure. The highest mass-based construction costs (CC, in kg glucose kg-1)were observed in leaves while the lowest CC in roots for all the 20 species plants studied. CC of tree species was higher than that of shrub and herb plants in the three forest communities. CC of the coniferous tree species was evidently higher than that of broadleaf tree species for either mass-based or area-based calculation. Based on area-based calculation, the total CC (t glucose hm-2) of canopy leaves was 17.1 for coniferous forest, 7.8 for Schima forest and 5.8 for A. mangium plantation, i.e., the CC of coniferous plantation was significantly greater than that of the other two broadleaf forest. Coniferous plantation had lower resource use efficiency, i.e., it needs expend more energy to construct the carbon skeleton of plants.
