新栽培区尾叶桉人工林的生物量和生产力

Biomass and Productivity of Eucalyptus urophylla Plantation in New Cultivated Areas

采用收获法和相对生长法对田林县不同年龄尾叶桉人工林的生物量和生产力进行了研究.结果表明:尾叶桉林分生物量随着年龄的增长而增加,0.4年生林分生物量为6.18 t/hm2,2.4年生林分为32.09 t/hm2,4.4年生林分为80.59 t/hm2;不同年龄林分的净生产量分别是14.82 t/(hm2.a)(0.4年)、13.02 t/(hm2.a)(2.4年)和19.90 t/(hm2.a)(4.4年);不同林分尾叶桉各器官生物量分配存在较大差异,在林分生长初期,以枝条和叶所占比例较高,干材比例较小,随着林分年龄的增长,干材和根的比例明显增大,叶的比例有所下降;不同年龄林分各器官生物量分配的大小顺序为:0.4年生林分为枝(37.54%)>叶(31.38%)>干材(14.77%)>根系(11.69%)>皮(4.62%),2.4年生林分为干材(50.83%)>根(18.43%)>枝(12.32%)>皮(10.22%)>叶(8.20%),4.4年生林分为干材(47.29%)>枝(18.42%)>根(14.73%)>叶(10.80%)>皮(8.75%);造林后第2年林分的平均枯梢率为84.62%,第3年为63.46%,枯长率分别为21.64%和27.15%.田林县尾叶桉具有较高的生物生产力,但林木干材比例偏低、枝和叶比例偏高以及枯梢严重等影响着林分的生长量和经济产量.

An investigation was conducted into the biomass and productivity of Eucalyptus utophylla at different age stands in Tianlin County where there is a new cultivated area for E. utophylla with the ＂harvest＂ and ＂relative growth＂ method. The results show that the biomass of E. urophylla stands increases with the increasing of stand age ; it is 6.18 t/hm^2 in the 0.4-year-old stand, 32.09 t/hm^2 in the 2. 4-year-old stand and 80. 59 t/hm^2 in the 4. 4-year-old stand; that the productivity of the different age stands is 14. 83 t/（hm^2 . a） （0. 4 year）, 13. 02 t/（hm^2 . a） （2.4 years） and 19. 90 t/（hm^2 . a） （4.4 years） respectively; that in the different age stands, there is difference in the biomass distribution of tissues： in the early stage, the rate of branch and leaf is higher and that of stem lower but with the increase of stand age, the rate of stem wood and root becomes significantly greater but the rate of leaf is down; that the biomass distribution of different stands ranges in the following order： branch （37. 54% ）〉leaf （31. 38%）〉stem （14.77%）〉root（11.69%）〉bark（4.66%） in the 0. 4-year-old stand, stem（50. 83%）〉root（18.43%）〉branch（12.32%）〉bark （10. 23%）〉leaf（8. 20%） in the 2.4-year-old stand, and stern（47.29%）〉branch（18.42%）〉root（14.73%）〉leaf（10. 80%）〉bark （8. 75%） in the 4.4-year-old stand respectively; and that the average dieback rate is 84.62% after planting 2 years and 63.46% after planting 3 years, and the rate of dieback length is 21. 64% and 27. 15% respectively. Although the productivity of Eucalyptus urophylla stands in Tianlin is high, the growth and economic yield are obviously affected because the rate of stem of Eucalyptus urophylla is low, the rate of branch and leaf high and the dieback severe.