Objective In order to study the accumulation process and its variation of biomass and productivity during the growth of Taiwania flousiana plantation, this paper provides a scientific basis for the management of T. flousiana plantation, especially the large-diameter timber plantations.
Method Taking T. flousiana plantation in Nandan County, Guangxi of southern China as the research object, the biomass, productivity and distribution characteristics of T. flousiana plantation at different age stages (9, 17, 25 and 37-year-old) were studied through sample plot investigation and biomass measurement.
Result (1) The tree layer biomass of 9, 17, 25, and 37-year-old T. flousiana plantation was 76.77, 157.06, 200.82 and 304.88 t/ha, respectively, 35.84, 90.10, 126.16 and 212.71 t/ha for the economic biomass (dry wood), 16.35, 28.68, 30.60 and 30.01 t/ha for the branch biomass, 11.26, 21.22, 24.16 and 39.92 t/ha for the root biomass, 9.95, 10.32, 11.72 and 9.88 t/ha for the leaf biomass, 3.38, 6.74, 8.17 and 12.36 t/ha for the dry skin biomass, respectively. (2) The biomass of undergrowth vegetation was 1.54, 3.38, 5.15 and 5.80 t/ha, respectively, of which the shrub layer accounted for 59.09%, 69.53%, 73.26% and 73.45%, the herb layer accounted for 40.91%, 30.47%, 26.74%, 26.55%, respectively. The litter layer biomass was 2.23, 4.73, 7.04 and 10.67 t/ha, respectively, which increased significantly with the increase of stand age. (3) The net productivity of the tree layer of investigated plantations was 8.53, 9.24, 8.03 and 8.24 t/(ha·year), respectively. The proportion of net productivity of dry wood (46.66%−69.78%) increased with the stand age, while the proportion of leaf and branch (3.28%−4.46% and 9.83%−21.34%) showed the opposite trend.
Conclusion (1) The biomass of tree layer increased with stand age in T. flousiana plantation. The proportion of economic biomass (dry wood) increased with the stand age, but it decreased in leaves, branches and bark. The roots showed a small fluctuation with the stand age. (2) Compared with Cunninghamia lanceolata and Pinus massoniana plantations, the T. flousiana plantation has the advantages of long fast-growing period and late recession, and high biological productivity. The results provide a basis for the sustainable management and development of plantation forests in northwestern Guangxi of southern China.
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