海南岛桉树林林下植被物种组成及生物量

对海南桉树林林下植被物种组成(153样地)及生物量(6样地)的调查结果表明:林下植被共有维管束植物224种,隶属于65科153属。其中:木本植物88种,占39.3%;草本类136种,占60.7%。人工桉树林林下植被结构简单、物种数相对较少。在未郁闭前的幼年桉树林地,林下植被地上部分生物量草本大于木本的现象更为突出。林下生物量局部有随年降水量增加而递增的趋势。不同土壤类型生物量大小的排序为:花岗岩砖红壤>花岗岩山地砖红壤>海相沉积物砖红壤>玄武岩砖红壤>冲积潮砂土。桉树幼年林分林下植被生物量最大,但生物量总体是随林龄增大而增加:1.5年生>9年生>8年生>7年生>6年生。

Species Component and Biomass of Understory Vegetation in Eucalyptus Plantation in Hainan Island

An experiment was conducted to study the species component and biomass of understory vegetations in Hainan Island by the survey method of field sample plot in eucalyptus plantations. Result shows that a total of 224 vascular bundle plants belonging to 65 families and 153 genera were recorded in the understory vegetation of the eucalyptus plantation. Eight-eight species of vascular bundle plants accounting for 39.3% of the total species are woody plants, while 136 species (60.7%) are herbs. In generally, the structure is simple and the species is relative scarce in the understory vegetation of the eucalyptus plantation. The above-ground biomass of herbs in the understory vegetations is higher than that of woody plants, especially in the unclosed young stands. The understory biomass increases with annual rainfall in some areas. Biomass of understory vegetations in different categories of soil shows that granitic laterite>granitic hill laterite>marine sediment laterite>basaltic laterite>fluviatile arenosol. The biomass of the understory vegetations in young eucalyptus stands is the highest, but it increases with forest age in some areas. Biomass of the understory vegetations varies with stand age in the following order 1.5 years, 9 years, 8 years, 7 years, 6 years from high to low.