亚热带森林不同恢复模式土壤与林下植被特征的动态研究

    Dynamics Study on Soil and the Characteristics of Understory Vegetation Under Different Restoration Modes in Subtropical Forests

    • 摘要: 选择亚热带自然恢复(次生林)和人工种植杉木两种恢复模式下不同林龄(5、8、21、27、40年)的林分为研究对象,通过测定0~10 cm土层土壤性质以及林下植被特征,探讨不同恢复模式下森林生态系统林下植被与土壤性质的恢复趋势以及相互作用过程。结果表明:随着林分发育,杉木林和次生林土壤碳氮储量均未发生显著变化,土壤C:N保持不变。林型对土壤碳氮储量有显著影响,在林龄5年和8年,次生林土壤碳氮储量显著高于杉木林。随着林分发育,杉木林土壤磷储量呈增加-降低-增加的变化趋势,在杉木成熟期27年达到最低,C:P和N:P最大。而次生林在发育过程中,土壤磷储量先下降后增加,在21年达到最低。100年次生林表层土壤碳氮储量与40年次生林相当,而磷储量却处于较低水平。相关分析表明,杉木林中灌木层盖度与土壤碳氮储量呈显著正相关。在林分发育5年和8年,杉木林灌木层盖度和丰富度均显著低于次生林,但随着时间的推移在27年时趋于一致。研究表明,杉木林在短期恢复中更有利于地上生物量的快速恢复,其经营措施增加了草本层的丰富度,但以牺牲林分发育前期灌木层的盖度和丰富度为代价;自然恢复能更快地形成复杂结构的森林群落。杉木营林过程中,可减少对林下灌木层植被的砍伐,保持一定的林下植被发育水平有利于土壤地力条件的改善和恢复。

       

      Abstract: The standing forests with different ages (5, 8, 21, 27, and 40 years) under two restoration modes of subtropical natural restoration (secondary forest) and artificial plantation of Cunninghamia lanceolata were selected as the research objects. By measuring the soil properties and the characteristics of understory vegetation in the soil layer of 0-10 cm, the restoration trend and interaction process of the understory vegetation and the soil properties in different restoration modes were discussed. The results showed that with the development of the stand, the carbon and nitrogen storage in soil of Cunninghamia lanceolata forest and secondary forest did not change significantly, and the soil carbon-nitrogen ratio remained unchanged. Forest type had a significant effect on the soil carbon and nitrogen storage, and the soil carbon and nitrogen storage in the secondary forest was significantly higher than that in Cunninghamia lanceolata forest at 5 and 8 years of stand age. With the development of the stand, the soil phosphorus storage of Cunninghamia lanceolata forest showed a trend of increasing-decreasing-increasing, and reached the lowest at 27 years of Cunninghamia lanceolata mature period, while the carbon-phosphorus ratio and nitrogen-phosphorus ratio reached the highest. However, during the development of the secondary forest, the soil phosphorus storage decreased first and then increased, and reached the lowest at 21 years of stand age. The carbon and nitrogen storage in the surface soil of the 100-year secondary forest was similar to that of the 40-year secondary forest, but the phosphorus storage was at a lower level. The correlation analysis showed that the coverage of shrub layer was significantly positively correlated with the soil carbon and nitrogen storage in Cunninghamia lanceolata forest. At 5 and 8 years of stand development, the coverage and abundance of shrub layer in Cunninghamia lanceolata forest were significantly lower than those in the secondary forest, but as time went on they tended to be the same at 27 years of stand age. The results showed that Cunninghamia lanceolata forest was more conducive to the rapid recovery of above-ground biomass in the short-term recovery, and its management measures increased the abundance of herbaceous layer. However, the coverage and abundance of shrub layer were sacrificed at the early stage of stand development. The natural restoration could form the complex forest communities more quickly. In the culture and management process of Cunninghamia lanceolata forest, the felling of vegetation in the understory shrub layer could be reduced, and maintaining a certain level of understory vegetation was beneficial to the improvement and restoration of the soil fertility conditions.

       

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