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尽管森林地被物在保水与养分循环中扮演重要角色,但我们仍然对由植被转换引起的森林地被物的变化缺乏了解。为评价不同人工林替代乡土灌丛对森林地被物水文特性的影响,我们选择了4种人工林(连香树Cercidiphyllum japonicum[Cj],油松Pinus tabulaeformis[Pt],华山松Pinus armandi[Pa],落叶松Larix kaempferi[Lk]),以次生乡土灌丛(QC)(Quercus liaotungensis和Corylus heterophylla var.sutchuenensis为优势种)为对照。人工林种植于1987年,初始密度为2500株ha-1。我们发现针叶人工林地被物厚度和贮量明显大于次生灌丛地和阔叶人工林地。地被物最大持水量在各林地之间差异与厚度和贮量显示相同的趋势,我们认为其主要贡献因子为林地凋落物数量及单位重量凋落物的最大持水量差异。地被物吸水过程和吸水速率与浸泡时间分别呈对数与指数回归关系。吸水过程在各植被之间与地被物各层次之间明显不同,主要受各植被的凋落物叶结构与分解程度影响。我们的结果显示针叶林地被物储量明显高于阔叶林,这说明以针叶树种为优势的林地大量养分滞留在凋落物中,难于返还土壤被植物利用,同时,半分解层(F)和分解层(H)最大持水能力高于未分解层(L),因此,改善林地微环境,促进L层地被物向F和H层转化,是改善人工林地被物水文功能的主要方法之一。
Although forest land cover plays an important role in water retention and nutrient cycling, we still do not understand the changes in forest cover caused by vegetation conversion. In order to evaluate the effect of different plantations on the hydrological characteristics of native forest shrubs, we selected four kinds of plantations (Cercidiphyllum japonicum [Cj], Pinus tabulaeformis [Pt], Pinus armandi [Pa ], Larix kaempferi [Lk]), and secondary native shrub (Quercus liaotungensis and Corylus heterophylla var.sutchuenensis) as control. Plantations were planted in 1987 with an initial density of 2500 ha-1. We found that the thickness and storage of coniferous plantations were significantly larger than that of secondary shrublands and broad-leaved plantations. The maximum water holding capacity of the ground cover tended to be the same as the thickness and stock in the woodlands. The main contributors were the number of litterfalls and the maximum water holding capacity of litter per unit weight. Groundwater absorption process and water absorption rate and immersion time were logarithmic and exponential regression. The process of water absorption is obviously different between the vegetation and the ground cover, which is mainly affected by the leaf structure and decomposition degree of the litter in each vegetation. Our results show that the amount of coniferous forest land cover is significantly higher than that of the broadleaf forest, which indicates that a large amount of nutrients in the coniferous forest land remain in the litter, making it difficult to return the soil for plant utilization. Meanwhile, the semi-decomposed layer (F) and The maximum water holding capacity of decomposition layer (H) is higher than that of undecomposed layer (L). Therefore, improving the microenvironment of forest land and promoting the conversion of L layer to the F and H layers is the main method to improve the hydrological function of plantations one.