Production and Turnover Rate of Fine Roots in Two Lower Subtropical Forest Sites at Dinghushan
WEN Da-Zhi, WEI Ping, KONG Guo-Hui, YE Wan-Hui
Chin J Plan Ecolo. 1999, 23 (4):
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Fine roots were sampled in a monsoon evergreen broad-leaved forest(MEBF),and a nearby mixed coniferous (Pinus massoniana ) and broad-leaved forest (MCBF), located in Dinghushan Biosphere Reserve. The standing pools of live and dead fine roots in the 0～40cm soil depth were sampled seasonally for one year, annual dry mass loss of the decomposing fine roots was measured and mortality and production were calculated. The comparison of soil coring and in growth method for estimating the fine-root production in the surface soil (0～20cm) was also made. The mean standing pools of roots ≤2mm and 2～5mm in the 0～40cm soil were 6.59 (29.9%) and 4.81(22.9%) t·hm-2 for the MEBF, while 5.35(34.4%) and 4.24(24.0%) t· hm-2 for the MCBF with the portion of dead roots given in parentheses. The standing pool did not fluctuate dramatically with various sampling occasions. In the MEBF, annual mass loss, mortality, net production for fine roots were 0.90,1.59,2.65t·hm-2·a-1 (≤2mm),and 0.41,0.63 and 1.25t·hm-2·a-1 (2～5mm),respectively. While the corresponding values in the MCBF were 0.80,1.41,2.42 t·hm-2·a-1 (≤2mm) ,and 0.37,0.62,1.21t·hm-2·a-1 (2～5mm) ,respectively. The annual turnover rates were 0.57(≤2mm) and 0.34 times·a-1(2～5mm) for the MEBF, and 0.69(≤2mm) and 0.38 times·a-1(2～5mm) for the MCBF, respectively.