陕北半干旱风沙区人工林下植物群落数量特征研究

Quantity characteristics of plant community under tree-layers of planted forests in semi-arid windy area of north Shaanxi Province

【目的】研究林下植物群落数量特征，为指导森林经营管理实践提供理论依据。【方法】采用标准地＋样方法对陕北半干旱风沙区（陕西靖边）人工林下的植物群落进行了调查，统计并计算了林下植物群落的生活型谱、盖度、优势度及物种多样性。【结果】（1）林下植物一般以隐芽植物和一年生植物种占绝对优势，所占比例为34％～88％。（2）林下植物的总盖度大小顺序为：旱柳林（26．18％）〉小叶杨×油松林、刺槐林（8．76％～11．77％）〉小叶杨林、小叶杨×柠条林（2．77％～3．16％）〉油松林、沙棘林、油松×柠条林、柠条林、天然草地（对照）（1．06％～1．57％）〉小叶杨×沙棘林、紫穗槐林（0．72％～0．77％）。除小叶杨×油凇林和小叶杨×柠条林地外，其他林地的草本层总盖度都大于灌木层。（3）林下优势植物种类差异不大，且以沙蒿（Artemisiadesertorum）、沙棘（Hippophae rhamnoides．）、狗尾草（Pennisetum alopecuroides）、羊胡子草（Carex rigescens）、沙蓬（Agriophyllum squarrosum）和冰草（Agropyron cristatum）为主。（4）林下植物的物种多样性指数和大小顺序为：旱柳林、刺槐林和小叶杨林（6．00～7．18）〉小叶杨×柠条林、小叶杨×油松林、油松林（4．87～5．38）〉沙棘林、油松×柠条林、柠条林、小叶杨×沙棘林（4．06～4．49）〉紫穗槐林、天然草地（2．15～2．76），且草本层物种多样性指数和均大于灌木层。【结论】陕北半干旱风沙区人工林下植物群落盖度及其物种多样性普遍较低，且阔叶树种林下植物群落一般比针叶树种和灌木林丰富，在针叶林中积极引进阔叶树种形成混交林，是增加林下植物多样性、维持人工林生态系统稳定性及可持续发展的有效途径。

[Objective] As plant community under tree-layer of forest is visual display of soil dynamics and affects the stability, sustainable development and functions of the ecosystem, study on the quantity characteristics of plant community under tree-layer of forest has great significance for the management practice of forests. [Methods] Method of Standard plot× Sample plot is taken to investigate the plants community and its diversity under tree-layers of planted forests in semi-arid windy area of north Shaanxi province （Jingbian county） . [Result] （1） Geophytes and therophytes are the major types （34%-88% of total species） in the life form spectrum of plants under tree-layers in planted forests. （2） The order of total plants coverage under tree-layers in planted forests is Saliz matsudana （26.18 %）〉Populus simonii× Pinus tabulae f ormis ,Robinia pseudoacia （8.76% -- 11.77%）〉Populus simonii and Populus simonii X Cara gana micro ph ylla （2.77 % -- 3.16 % ） 〉 P inus tabulae f ormis , H i p po phae rhamnoides , P inus tabulae fo-mis× Caragana microphylla, Caragana microphylla and natural grassland （CK） （1. 06% -- 1. 57%） Populus simonii X Hippophae rhamnoides and Amorpha f ruticosa （0.72%-0.77%）. （3） The dominant species under tree-layers are similar to planted forest types,in which, shrubs dominate with Artemisia desertorurn and Hippophae rhamnoides while herbs dominate with Pennisetum alopecuroides, Carez rigescens ,Agriophyllum squarrosum and Agropyron cristatum. （4） The order of indexes sum of plant diversity under tree-layers of forests is Salix matsudana, Robinia pseudoacia, Populus simonii （6. 00 - 7. 18） Populus simonii ×Caragana microph ylla , Populus simonii × P inus tabulae f orrnis and P inus tabulae forrnis （4.87--5.38）〉Hippophae rhamnoides , P inus tabulae f orrnis × Caragana microph ylla , Caragana microphylla and Populus simonii × Hippophae rhamnoides （4.06--4.49）〉Amorpha fruticosa and natural grassland （CK） （2.15--2.76）. The species diversities of herbal layers in all planted forests are more than that of shrubs layers. [Conclusion] Coverage and species diversities of plant communities under tree layer of planted forests in semi-arid windy area of North Shaanxi Province are generally lower and richer in broad-leaved forests than in needle-leaved forests and shrubs. So, introducing broad-leaved trees into nee die-leaved forest and forming mixture is an available way to increase plant diversity under treeqayer and maintain ecosystem stability and sustainable development of planted forest.