暖温带-亚热带过渡区鸡公山落叶栎林和松栎混交林 土壤有机碳空间分布特征

河南省鸡公山位于暖温带-亚热带过渡区,落叶栎类栓皮栎(Quercus variabilis Blume.)和麻栎(Q.acu-tissima Carr.)混交林和马尾松(Pinus massoniana Lamb)栎类混交林是该区域的2种典型林分类型。分别在海拔200、400和600 m的落叶栎林和松栎混交林中设置样地,比较土壤有机碳(SOC)含量和碳密度的变化。结果表明,随着海拔升高,2种类型林分的土壤有机碳含量和密度显著增加(P0.05);在200和400 m海拔高度上,松栎混交林分土壤有机碳密度高于落叶栎林。在600 m海拔高度上,落叶栎林土壤有机碳密度高于松栎混交林。对于各个海拔高度林分来说,土壤有机碳含量和密度随着土壤深度增加而降低,0～20 cm土层有机碳密度对剖面总有机碳贡献率为77%～93%。这些结果揭示该地区森林土壤有机碳分布特点,也为当地碳汇林业的经营提供了依据。

Spatial patterns of soil organic carbon in oak and pine-oak mixed forests in Jigong Mountain in temperate-subtropical ecotone

Jigong Mountain, Henan Province in central China, is located in temperate-subtropical ecotone, with deciduous oak (Quercus variabilis Blume. and Q. acutissima Carr.) mixed stands and pine (Pinus massoniana Lamb) and oak mixed stands as dominated forest vegetation. The spatial distribution characteristics of soil organic carbon (SOC) in two typical forests were investigated. The results showed that there was a significant increase in both SOC concentration and SOC density in the two types of forests with increasing altitude (p < 0.05). At the altitudes of 200 and 400 m, SOC density in pine-oak mixed stands was higher than that in the oak mixed stands. At the altitude of 600 m, however, the oak mixed stands displayed higher SOC density than the pine-oak mixed stand did. The SOC concentration and SOC density decreased with the increase of the soil depth in the two types of stands, with a SOC density of 77% to 93% in 0-20 cm soil to the total profile. These results suggested there was a distinct variation in SOC concentration and density with soil depths, forest types and altitudes, implying that tree species and forest types should be taken into account when carbon-sink forests were managed in this area.