短周期尾巨桉连栽林分生产力的研究

A Study on the Biomass Productivity of 3.6 Year-old Eucalyptus urophylla × E.grandis Plantation in Successive Rotation

采用空间代替时间和定位观测相结合的方法对广西东门林场3．6年生尾巨桉林分生物量和生产力的连栽效应进行了研究。结果表明：林分平均单株生物量及林分生物量3代〉1代〉2代，不同代数尾巨桉器官生物量的大小顺序为干材〉干皮〉根蔸〉粗根〉光枝〉叶〉枯枝〉叶枝〉吸收根〉细根，地上与地下部分的比例分别为84．48％-84．75％和15．25％～15．52％；不同代数林分乔木层生产力为3代〉1代〉2代，连栽对尾巨桉林分生产力的影响有待进一步的研究。

This study adopted the ＂time specific＂ and ＂fixed position＂ method to investigate synthetically the stand biomass productivity of 3.6 years old Eucalyptus urophylla x E. grandis plantation. The research results showed ： The biomass of individual tree and stands exhibited the pattern ： the third generation plantation 〉 the first generation plantation 〉 the second generation. The biomass distribution of tissues of E. urophylla x E. grandis in the different plantations generation was in the sequence of stem 〉 bark 〉 stump 〉 stout root 〉 branch 〉 leaf 〉 dead branch 〉 twig 〉 absorptive root 〉 fine root. The proportions of above and underground biomass ranged from 84.48% to 84.75% and from 15.25% to 15.52%. The productivity of the tree layer of different generations in Dongmen was in the order：the third generation 〉 the first generation 〉 the second generation, and yet the productivity of E. urophylla x E. granis stands didn＇t change regularly with the increase of plantation generations.