海岸带风口沙地木麻黄无性系造林与根系生长特性

Afforestation and Root System Growth Characteristics of Casuarina equisetifolia Clones Grown on the Sandy Land in the Draught in the Coastal Zone

从 2 0 0 0年 5月起在福建省东山县赤山林场临海风口干旱沙地进行 3年试验研究 ,从 7个参试无性系中选择惠 1#、粤 70 1#、东 980 1#等 3个造林保存率达 6 1 9%～ 6 9 5 %的无性系 ,在此类特殊困难立地防护林植物材料选择方面取得突破。通过对风口沙地前沿高地和后沿低洼地 2种微地形条件木麻黄无性系造林效果的比较分析 ,后者造林保存率提高约 5 % ,且林木生长较快。 2种微地形条件林木根系生长状况 ,风口前沿高地林木根系分布深、数量多、结构密集、吸收根系网络发达 ,有助于逃避大气干旱和土壤干旱。并揭示根系分布深度、数量、密集程度、网络结构与土壤含水率大体呈负相关的趋势。研究揭示 ,风口干旱沙地造林成活的机制 ,是由于林木形成发达、庞大的根系网络的生理和形态特性 ,以适应干旱生境和保证造林成活。不同造林方式的试验结果表明 ,丛状、团状等植生组造林方式可提高保存率约 10 % ,在生产实践上有推广应用价值。

This study was carried out on the dry sandy land in the draught facing the sea in Chishan Forest Farm of Dongshan County,Fujian Province since May,2000.Through the experimental study for 3 years,3 clones of Hui 1+#,Yue 701+# and Dong 9801+#, whose preserving rate for the afforestation reached 61.9%～69.5%,were selected from 7 tested clones.Thus,the significant breakthrough has been achieved in the respect of selecting plant materials for the afforestation on sites with such special difficulty.By means of the comparative analysis of the planting effects of Casuarina equisetifolia clones on 2 types of micro_topography sites of the forward position of highland and the back_edge of low_lying land of the sandy land in the draught of bordering on the sea, the preserving rate of trees planted on the latter site for afforestation raised by 5%,and forest trees grew faster.The growth status of the root system of forest trees grown on both micro_topographies sites indicated that on the smooth highland in the draught,the distribution of the root system was deep,the numbers were large,the structure was concentrated,and the absorptive network was developed,which was conducive to evade the atmospheric aridity and soil aridity.It also revealed the tendency of a negative correlation between the distribution depth,quantity, concentrated degree and network structure of the root system and the moisture content of the soil.The study showed that the mechanism of the planting survival on the dry sandy land in the draught was the physiology and morphological characteristics of forest trees forming the enormous and developed root system network so as to be suitable for the dry habitat and to guarantee the planting survival.The experimental results of different planting modes showed that the planting modes of clump,mass,etc.may raise the preserving rate by about 10%,thus possess the extensive popularization and application value in the productive practice.