Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
HE Bin, HUANG Heng-chuan, HUANG Cheng-biao, HUANG Hai-zhong, Wu Qing-biao
Taiwania flousiana,a rare species endemic to China, is naturally distributed to the southwestern part of Hubei province, the southeastern part of Guizhou province and the west of Yunnan province. Due to the virtue of high adaptability, fast growth, high timber ratio and timber quality, T. flousiana has been successfully introduced to the southern part of China since the 1970s. In order to understand the nutrients characteristics in T. flousiana plantation, the concentrations, accumulation and distribution of five nutrient elements (N, P, K, Ca and Mg) as well as their changes with growth of stands in T. flousiana plantations of three different stand ages (8-year old,14-year old and 28-year old) were studied in Nandan Shankou Forestry Farm of Guangxi,China. The results showed that concentrations of these five nutrient elements in different components of T. flousiana plantation were in the order of leaves > bark > branch > root > stem. And in different diameters of the root (expect Stump), nutrient concentrations reduced with the increase of root diameter. In plant, concentrations of N, Ca or K were the highest among the five elements, followed by P, while Mg was the lowest in various organs of T. flousiana plantation and in the litter. The total nutrient accumulations at three different stand ages plantations were 576.26 kg/ha, 833.20 kg/ha and 1214.11 kg/ha, respectively. Of the total storage of nutrients, 85.88%-92.89% was distributed in arbor layer, 2.01%-4.62% in forest floor layer and 5.10%-10.27% in standing litter layer. Among five elements, N or Ca accumulation in arbor layer was the highest and Mg accumulation in arbor layer was the lowest. The accumulations of nutrients in T. flousiana varied with different stands growth stages. Most nutrient elements accumulated in leaves and branches at 8-year-old and 14-year-old trees, while they transmitted gradually to the stem and bark at 28-year-old trees. The net production of organic matter per ton needed five elements in plantations from 4.21kg to 8.97 kg and decreased with the biomass accumulation in the process of the stands growth. And the N or Ca element amount was the biggest, then the K and Ca, and the Mg was the smallest among the five nutrient elements.