秦岭火地塘天然次生油松林间草本层碳密度

Carbon Density of Herbage in Natural Secondary Pinus tabulaeformis Forest in Huoditang Zone,Qinling Moutains

为精确估计秦岭火地塘林区天然次生油松(Pinus tablaeformis)群落的碳密度,以林下草本层为研究对象,采用分层抽样法确定在既定精度下的调查样方数量。通过草本生物量调查,以TOC-VTH-2000A型TOC分析仪测定不同器官含碳率,分析不同草种相同器官和同一草种不同器官含碳率的差异,结合器官生物量及草种密度,推算其碳密度。结果表明:不同草种茎、根的含碳率间差异显著(P<0.05)或极显著(P<0.01),茎与茎、根与根的含碳率差值最高分别达14.46%和26.06%;同一草种的叶与茎、茎与根及叶与根的含碳率间差异显著或极显著(P<0.05或P<0.01),差值最高分别达11.31%、16.83%和19.86%;在95%的可靠性下,误差±0.0198 MgC.hm-2时,草本层碳密度的估计值为1.829 MgC.hm-2,占乔木地上部碳密度的3.660%。

Herbage layer in forest is one of main parts of the whole forest ecosystem and plays vital roles in adjusting carbon balance, decreasing concentration of carbon dioxide and delaying climate change in the global scale. Carbon density of the natural secondary Pinus tabulaeforims Carr. forest ecosystem was esti- mated using stratified sampling method applied to definite quantities of herbage plots under a given accuracy in Huoditang forest zone, Qinling Mountains. Biomasses of herbage layers were investigated and the carbon content rate （CCR） of organs in various herbage species was measured by TOC-VTH-2000A analyzer. Differences of CCR in same organs among various herbage species and in various organs of the same herbage species were analyzed respectively. Carbon density of herbage layer in the study area was estimated by combining CCR of organs in various herbage species with their biomass and densities. The findings indicate as follows： significant or extremely significant differences occurred in CCR of roots or stems among various herbage species and the maximum CCR difference for stems or roots was 14. 46% and 26.06%, respectively; significant or extremely significant differences also existed in CCR of leaves and stems, stems and roots, leaves and roots in same herbage species and the maximum CCR difference between leaves and stems, stems and roots, leaves and roots was 11.31%,16.83%, and 19.86%, respectively; average carbon density in herbage layer was estimated at 1. 829 MgC ·hm^-2 by the accuracy of 95% and error scale±0. 0198 MgC ·hm^-2 and was 3. 660% of the carbon density in aboveground parts of the forest.