滨海沙地不同树种人工林生物量及凋落物碳氮养分归还

基于福州市滨海后沿沙地上营造的人工林的调查,以9年生尾巨桉(Eucalyptus urophylla×E.grandis)、木麻黄(Casuarina equisetifolia)、纹荚相思(Acacia aulacocarpa)3种主要人工林为对象,采用Monsi分层切割法(乔木层)和样方收获法(草本层、凋落物层)获取这3种人工林的生物量,研究其生物量分配格局及凋落物碳氮养分归还。结果表明,尾巨桉乔木层地上部分生物量为49.950t·hm^-2,地下部分生物量为15.270t·hm^-2,分别占生态系统总生物量的62.08%和18.98%;草本层生物量为0.698t·hm^-2(0.87%);凋落物层生物量为14.539t·hm^-2(18.07%)。木麻黄乔木层地上部分生物量为51.630t·hm^-2,地下部分为20.270t·hm^-2,分别占生态系统总生物量的62.65%和24.60%;草本层生物量为0.017t·hm^-2(0.02%);凋落物层生物量为10.488t·hm^-2(12.73%)。纹荚相思乔木层地上部分生物量为51.130t·hm^-2,地下部分为13.760t·hm^-2,分别占生态系统总生物量的64.43%和17.34%;草本层生物量为0.093t·hm^-2(0.12%);凋落物层生物量为14.369t·hm^-2(18.11%)。3种人工林地上各器官生物量均表现为:树干>树枝>树皮>树叶。这3种人工林生态系统总生物量与乔木层生物量排序相同,表现为木麻黄(82.40t·hm^-2)>尾巨桉(80.46t·hm^-2)>纹荚相思(79.35t·hm^-2),且生物量分配格局均为乔木层>凋落物层>草本层。3种人工林的净生产力表现为木麻黄(16.21t·hm^-2·a^-1)>尾巨桉(14.00t·hm^-2·a^-1)>纹荚相思(12.51t·hm^-2·a^-1)。凋落物碳氮养分年总归还量表现为木麻黄(3.953t·hm^-2·a^-1)>尾巨桉(3.329t·hm^-2·a^-1)>纹荚相思(2.751t·hm^-2·a^-1)。

Biomass and Litter Carbon and Nitrogen Return of Different Plantations in the Sandy Coastal Plain Area

Based on the survey of primary plantations in southeast coastal area of Fuzhou,the biomass allocation pattern and litter carbon and nitrogen return of Eucalyptus urophylla×E.grandis,Casuarina equisetifolia and Acacia aulacocarpa were investigated by obtaining their biomass with Monsi stratified cutting (the tree layer) and sample harvest method (the herb layer and the litter layer).The results showed that the aboveground biomass of the tree layer of E.urophylla×E.grandis was 49.950 t·hm^-2 and the underground biomass was 15.270 t·hm^-2 .They accounted for 62.08% and 18.98% of the total biomass of the ecosystem respectively.The biomass of the herb layer was 0.698 t·hm^-2 (0.87%),and the biomass of the litter layer was 14.539 t·hm^-2 (18.07%).The aboveground biomass of the tree layer of C.equisetifolia was 51.630 t·hm^-2 and the underground biomass was 20.270 t·hm^-2 .They accounted for 62.65% and 24.60% of the total,respectively.The biomass of the therb layer was 0.017 t·hm^-2 (0.02%),and the biomass of the litter layer was 10.488 t·hm^-2 (12.73%).The aboveground biomass of the tree layer of A.aulacocarpa was 51.130 t·hm^-2 and the underground biomass was 13.760 t·hm^-2 .They accounted for 64.43% and 17.34% of the total biomass,respectively.The biomass of the herb layer was 0.093 t·hm^-2 (0.12%),and the biomass of the litter layer was 14.369 t·hm^-2 (18.11%).The biomass of different organs on the ground of the 3 plantations were all shown as trunk >root >branch >bark >leaf.The order of the ecosystem biomass of these 3 plantations was the same as that of the tree layer, C.equisetifolia (82.40 t·hm^-2 ) > E.urophylla×E.grandis (80.46 t·hm^-2 ) > A.aulacocarpa (79.35 t·hm^-2 ),and the biomass distribution pattern was tree layer >litter layer >herb layer.The net productivity of the 3 plantations was shown as C.equisetifolia (16.21 t·hm^-2 ·a^-1) > E.urophylla×E.grandis (14.00 t·hm^-2 ·a^-1) > A.aulacocarpa (12.51 t·hm^-2 ·a^-1).The total annual return of carbon and nitrogen nutrients in litter was shown as C.equisetifolia (3.953 t·hm^-2 ·a^-1) > E.urophylla×E.grandis (3.329 t·hm^-2 ·a^-1) > A.aulacocarpa (2.751 t·hm^-2 ·a^-1).