ABSTRACT

We investigated the influence of dominant tree species and seasonal variation of the soil respiration rates in the temperate forest of the Indian Himalayan region. Ten dominant tree species based on the ecological parameters were selected for the study; seven were evergreen (Abies pindrow, Cedrus deodara, Cupressus torulosa, Eunonymous pendulous, Pinus wallichiana, Quercus leucotrichophora, and Rhododenderon arboreum) and three were deciduous (Aesculus indica, Pyrus paschia, and Toona ciliata). Soil respiration was highest under the canopy of Eunonymous pendulous i.e. 25.33 μmol CO₂ m⁻² s⁻¹ and lowest under Rhododenderon arboreum i.e. 0.10 μmol CO₂ m⁻² s⁻¹ tree species. The trend of canopy influence of tree species on soil respiration followed the order of Eunonymous pendulous > Aesculus indica >Abies pindrow> Pyrus paschia >Cedrus deodara >Pinus wallichiana >Cupressus torulosa >Toona ciliata > Quercus leucotrichophora > Rhododenderon arboreum. Seasonally, soil respiration was higher during the rainy season when litter decomposition is at its peak and lowers in winter. There is a positive correlation of soil respiration with soil physicochemical properties i.e. soil pH, soil moisture, total carbon, microbial biomass C and N. However, negative correlations were detected between soil respiration and microbial biomass P, and total P. Overall results clearly define the differential influence of trees species growing in a given forest on the soil CO₂ efflux in a temperate forest ecosystem, thus warranting further research on the functional trait-based analysis on the overall biomass dynamics on the forest floor vis-à-vis CO₂ and nutrient flux in the topsoil.

摘要

我们调查了印度喜马拉雅地区温带森林中优势树种和土壤呼吸速率季节性变化的影响。根据生态参数选择了十种优势树种进行研究；7 种常绿植物（冷杉、雪松、桧木、花楸、松树、白毛栎和红杜鹃），3 种落叶植物（七叶树、美洲梨和香椿）。土壤呼吸在Eunonymous pendulous树冠下最高，即 25.33 μmol CO ₂ m ^-2 s ^-1和最低Rhododenderon arboreum即 0.10 μmol CO ₂ m ^-2 s ^-1树种。树种冠层对土壤呼吸影响的变化趋势为：黄杨>七叶树>冷杉>洋梨>雪松>华勒松>松柏>香椿>白花栎>乔木. 季节性地，土壤呼吸在雨季较高，此时凋落物分解达到顶峰，冬季较低。土壤呼吸与土壤理化性质（即土壤 pH 值、土壤水分、总碳、微生物生物量 C 和 N）呈正相关。然而，在土壤呼吸与微生物生物量 P 和总 P 之间检测到负相关。总体结果明确定义特定森林中生长的树种对温带森林生态系统中土壤 CO ₂流出的不同影响，因此需要进一步研究基于功能性状的森林地面整体生物量动态相对于CO _{2 的分析}和表土中的养分通量。