| Balang Mountain which is located in the southwest part of Sichuan Wolong Nature Reserve in the western Sichuan, is the typical region of the continuous distribution of Quercus aquifolioides, and it belongs to the subtropical inland mountain climate. Concentrated between river valleys and alpine meadows which is from2200to3600m on the sunny slope of the Balang Mountain, the Quercus aquifolioides shrubbery is an important vegetation type in the Subalpine Timberline Ecotone and plays an important role in the region’s soil and water conservation and water source conservation. This study, during the growing season in2011, researches the fine root bio mass of the Quercus aquifolioides which is in six elevation gradient of2600m,2800m,3000m,3200m,3400m and3600m on Balang Mountain by using the excavation method; compares the biomass of total fine root, live fine root and dead fine root in time dynamic changes, in elevation distribution and the vertical distribution in the different layers and estimates the carbon reserves of Quercus aquifolioides fine root in the region. The main results are as follows:(1) The average biomass of Quercus aquifolioides ’total fine root is0.83±0.24t·hm-2, and the total fine root biomass is0.55±0.04～1.57±0.82t·hm-2in different altitudes and months. Among this, the live fine root biomass is0.49～1.43t·hm-2and the dead fine root biomass is0.03～0.14t·hm-2which is86.08～96.48%and3.52～13.9%of the total fine root biomass respectively.(2) During the growing season in2011, the temporal dynamics of the average biomass of Quercus aquifolioides’ total fine root, live fine root and dead fine root, show fluctuation between April and October, and achieve the maximum in August. The fine root biomass was significantly different between August and the other months (p<0.05), and the difference among the other months is not significant (p>0.05). The temporal dynamics trend of the fine root biomass trended is inconsistent in different altitudes and layers, which showed both fluctuation and a single peak, meanwhile the former is the main. The dynamics of the fine root biomass don’t show a significant time lag in20-50cm soil layers, except3400m above sea level.(3) The distribution of the Quercus aquifolioides’ fine root biomass is apparently vertical. The average biomass of the total fine root in0-20cm soil layer is0.66t·hm-2, accounting for the all fine root biomass of80.72%. The live fine root biomass is0.63t·hm-2, accounting for the total live fine root biomass of81.82%; The dead fine root biomass is0.04t·hm-2, accounting for the total dead fine root biomass of80.00%. The difference of the Quercus aquifolioides’ total fine root biomass, live fine root biomass and dead fine root is significant in different layers.(4) The annual average biomass of the total fine root is significantly different from the elevation gradient (p<0.01). In3600m,3400m,3200m,3000m,2800m,2600m elevation gradient, the annual average biomass of the total fine root is0.76t·hm-21.07t·hm-2、0.64t·hm-2、0.74t·hm-2、0.99t·hm-2、0.78t·hm-2, which show a bimodal distribution with tow peaks in3400m and2800m. The largest fine root biomass is in3400m gradient.(5) In the research area, the average carbon content of the fine root is50.55%. The carbon content of the fine root is between43.29%and54.32%in different altitudes, months and soil layer. The maximum is in August in the altitude of2600m,0～20cm soil layer; the minimum is in April in the altitude of3000m,20～50cm soil layer. The carbon content of the fine root isn’t remarkable in elevation gradient and soil layer, but in months remarkable related (p<0.05).(6) The carbon content of the Quercus aquifolioides’ fine root is0.42t·hm-2in the research area. In2600m、2800m、3000m、3200m、3400m and3600m elevation gradient, the carbon content is0.39t·hm-2、0.52t·hm-2、0.37t·hm-2、0.32t·hm-2、0.55t·hm-2and0.39t·hm-2.The carbon content of the fine root isn’t remarkable in elevation correlation, but soil layer in0.01level remarkable related. |
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