| Mytilaria laosensis is one of the Hamamelidaceae evergreen broad-leaved species, which came from Vietnam, Laos and Guangdong, Guangxi, Yunnan province. As one of the fast growing tree species, Mytilaria laosensis has a lot of nice properties such as fast-growing, environment adaptiveness and trunk is sreaight. In order to objective evaluation to this species, we focused research 34-year-old Mytilaria laosensis plantation on forest biomass, feature of the nutritive elements and carbon accumulation. The research site was chosen in Paiyangshan forest Farm. The aim of this study was to uncover the forest biomass, feature of the nutritive elements and carbon accumulation one Mytilaria laosensis plantation. At the same time, to afford a theoretical foundation for Mytilaria laosensis plantation’s operation and management. The primary findings are as follows:(1) The biomass accumulations of arbor layer of Mytilaria laosensis plantation was 293.38 t/hm. Different organs have different proportion. The trunk has the highest ratio (63.35%). The ratio of root, branch and bark were 21.11%,9.85% and 4.07%. The smallest proportion of arbor layer was leaf (1.62%). The shrub layer biomass was 0.92t/hm2. The herb layer biomass was 0.38 t/hm2.(2) The annual net productivity of 34-year-old M. laosensis plantation was 8.63 t/(hm2·a). There were different accumulation rates in different organs. First of all, stem hold the fastest accumulation rate(5.47 t/(hm2·a)). Secondly, leaf, root and branch were fllowing, which separately 2.39 t/(hm2·a),1.83 t/(hm2·a) and 0.85 t/(hm2·a); the slowest organ was bark 0.35 t/(hm2·a).(3) Changes in nutrient elements (N, P, K, Ca and Mg) of M. laosensis plantation (nutrient contents for different organs in the M. laosensis plantation in the order of leaves> branch> bark>root> stem. In all of the macroelements, except branch, N was the first content, the second macroelements was Ca and K, the last level was P and Mg.(4) The total nutrient accumulation in M. laosensis plantation was 1671.85 kg/hm. Of the total accumulation of nutrients,89.55% was distributed in arbor layer,1.37% at forest floor layer,9.08% at standing litter layer.(5) The annual net nutrient stockpile of arbor layer is 44.03 kg/(hm2.a). The order of annual net stockpile of different organ was:stem> branch> bark> leaf> root. In order to fabricate one ton dry-matter, Mytilaria laosensis will spend 5.10 kilogram macroelements. The annual net nutrient accumulation is higher than the same age of Pinus massoniana plantation.(6) The capacity of carbon storage in ecosystem of M. laosensis plantation was 272.80 t/hm2. The capacity of carbon storage in arbor layer was 143.47 t/hm. The sequence of carbon storage in different organs was:stem>root> branch>bark> leaf. The capacity of carbon storage in shrub grass layer was 0.62kg/hm2 and litter layer’s was 5.07t/hm2, the soil layer’s was 123.64t/hm2.(7) The annual carbon net fixation of arbor layer was 5.37 t/(hm2-a), which converted into carbon dioxide was 19.69 t/(hm2·a).Through this research, we found M. laosensis is an excellent native tree which is suitable for cultivation in the south of China. Its advantages included fast growth, high productivity and strong carbon sequestration capacity. A reasonable plan and scientific management will help people to improve M. laosensis plantation’s carbon sequestration ability. Meanwhile, its may play an important role to enhance plantation’s productive forces and maintain or improve soil fertility. |
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