暖温带-亚热带过渡区鸡公山不同海拔天然松栎 混交林生态系统碳库特征

河南省鸡公山位于暖温带-亚热带过渡区,马尾松(Pinus massoniana Lamb)栎类混交林是该区域的典型林分类型。分别在鸡公山海拔200、400和600 m的天然松栎混交林分中设置样地,调查分析松栎混交林生态系统土壤碳密度和碳储量,测定林下植被层和凋落物层碳储量,用生物量方程法估测了乔木层各组分的生物量及碳储量,并与鸡公山天然落叶栎林生态系统总碳储量作了比较分析。结果表明,松栎混交林生态系统总碳储量为179.74t·hm-2,空间分布特征表现为乔木层(97.57 t·hm-2)土壤层(70.56 t·hm-2)凋落物层(10.57 t·hm-2)灌木层(0.83 t·hm-2)草本层(0.21 t·hm-2)。在不同采样层次上碳含量存在显著差异。200、400和600 m 3个海拔高度上,松栎混交林生态系统仅在土壤层碳储量存在显著差异(P0.05),其他各层次差异均不显著;土壤层碳储量随着海拔升高而显著增加,随着土层深度增加而显著降低(P0.05)。松栎混交林生态系统总碳储量与林分密度正相关,随着样地林分密度的增加而呈现上升趋势。松栎混交林总碳储量高于落叶栎林,但二者之间没有显著差异。这些结果揭示了该地区松栎混交林生态系统碳储量的分布特征,也为当地碳汇林业的经营提供了依据。

Carbon storage in a mixed pine-oak forest ecosystem at different altitude in Jigong Mountain, a temperate-subtropical ecotone

This study was carried out in the Jigong Mountain, a temperate-subtropical ecotone, where there is extensive mixed pine-oak forest. Three study sites were established at the altitudes of 200, 400, and 600 m, respectively. The soil carbon density and total carbon storage in the mixed pine-oak forest were determined. The carbon storage in the vegetation layer under the canopy and the litter were also measured. The biomass and carbon storage of the tree layer was estimated using biomass equations. The carbon storage of the mixed pine-oak forest was compared with that of the deciduous oak forest. The results suggested that the total carbon storage of the mixed pine-oak forest ecosystem is 179.74 t·hm^-2 and the carbon storage in each individual layers of the mixed pine-oak forest was different with a decreasing order of tree layer (97.57 t·hm^-2) > soil layer (70.56 t·hm^-2) > litter layer (10.57 t·hm^-2) > shrub layer (0.83 t·hm^-2) > herb layer (0.21 t·hm^-2). However, the stored carbon contents at the layers (except for soil layer) with different altitudes were not significantly different. Soil carbon storage significantly increased with an increase of the altitude and decreased with the increasing depth (P < 0.05). We also found that carbon storage of the mixed pine-oak forest was positively related to forest canopy and it was higher than that of the deciduous oak forest. Those results help us understand the spatial distribution characteristics of the mixed pine-oak forest ecosystem and can facilitate the management?of the forest as a?carbon?sink.