桂西北不同年龄阶段秃杉人工林的生物量积累及生产力变化

【目的】研究秃杉人工林生长过程中生物量和生产力的积累过程及其变化规律,为秃杉人工林尤其是大径级用材林经营管理提供科学依据。【方法】以广西南丹县秃杉人工林为研究对象,采用样地调查与生物量实测方法,研究了不同年龄阶段(9、17、25、37年生)秃杉人工林生物量、生产力及其分配特征。【结果】(1)乔木层生物量随林龄增加而增大,9、17、25、37年生的秃杉人工林生物量分别为76.77、157.06、200.82、304.88 t/hm²,其中经济生物量(干材)分别为35.84、90.10、126.16、212.71 t/hm²,树枝生物量分别为16.35、28.68、30.60、30.01 t/hm²,树根生物量分别为11.26、21.22、24.16、39.92t/hm²,树叶生物量分别为9.95、10.32、11.72、9.88 t/hm²,干皮生物量分别为3.38、6.74、8.17、12.36 t/hm²。(2)林下植被生物量依次为1.54、3.38、5...

Biomass accumulation and productivity changes of Taiwania flousiana plantation at different age stages in northwestern Guangxi,southern China

  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.