喜玛拉雅嘎瓦耳地区的坡向对温带自然森林的森林成分,群落结构和土壤特性的影响

在喜玛拉雅嘎瓦耳（Garhwal Himalaya）地区,选择7种温带（1500 to 3100 m,a.s.l.）森林类型,研究不同坡面（东北,西北,东南,西南）对自然森林的森林成分、群落结构和土壤特性的影响。在每种森林中自由采样。为了阐明研究不同坡面（东北、西北、东南、西南）对天然森林的森林成分、群落结构和土壤特性的影响,利用标准统计软件计算多种指标,如,重要价值指标、Shannon-Wiener多样性指数、优势辛普森浓度、辛普森多样性指数、种均匀度和物种丰富度指数。在每种森林中采集复合土壤样品,分析土壤的物理化学特性、水分含量、持水量、pH、有机碳、磷、钾和有效氮含量。结果表明,北坡森林的总基盖度（高山栎林Quercus semecarpifolia为74.4 m2·ha-1）、优势度（长叶松林Pinus roxburghii为0.85）和树种多样（石斛蟹Quercus floribunda为1.81）均高于其他坡位森林,北坡森林土壤中的水分含量（白橡树Quercusleucotrichophora为40.8%）、持水量（藏柏Cupressus torulos为48.9%）、有机碳（雪松Cedrus deodara为3.8%）、磷（白橡树Quercus leucotrichophora为31.9 kg·ha-1）和氮（西藏长叶松林Pinus roxburghii为1.0%）均比其他坡位土壤值高。因此,北坡森林的生产力较高。

Effects of slope aspects on forest compositions,community structures and soil properties in natural temperate forests of Garhwal Himalaya

The present study was undertaken in seven natural forest types of temperate zone (1500 to 3100 m, a.s.l.) of Garhwal Himalaya to understand the effects of slope aspects viz., north-east (NE), north-west(NW), south-east (SE) and south-west (SW), on the forest structure,composition and soil characteristics of each selected forest type. The sample plots in each forest type were laid out by using stratified random approach. The indices i.e., the Importance Value Index, Shannon-Wiener diversity index, Simpson's concentration of Dominance, Simpson diversity index, Pielou equitability and Margalef species richness index were calculated statistically using standard softwares to elucidate the differences in forest structure and composition of forest types on different slope aspects of the sites. The composite soil samples were taken from each forest stand and the physico-chemical properties of the soil i.e.,moisture content (MC), water holding capacity (WHC), pH, organic carbon (OC), phosphorus (P), potassium (K) and available nitrogen (N)were analyzed. The results show that the higher values of total basal dominance (0.85 in Pinus roxburghii forest) and Tree diversity (1.81 in Quercus floribunda forest) in the forests were recorded in the northern aspects. MC (40.8% in Quercus leucotnchophora forest), WHC (48.9%in Cupressus torulosa forest), OC (3.8% in Cedrus deodara forest), P (31.9 kg.ha-1 in Quercus leucotrichophora forest) and N (1.0% in Pinus roxburghii forest) had also higher values in the soils of northern aspects.Consequently the higher productivity of the forests was also noticed on the northern aspects.