植被恢复模式对石漠化生态系统碳储量的影响

为揭示石漠化生态系统碳储量对植被恢复模式的响应,在广西天等县中度石漠化山地,研究了吊丝竹纯林(Dendrocalamus minorD)、任豆纯林(Zenia insignis Z)、任豆、蚬木(Buerretiodendron hsienmu)和顶果木(Acrocarpus fraxinifolius)混交林(mixed plantation M),以及相应同龄封育林(D_(CK)、Z_(CK)、M_(CK))的碳储量。结果表明:人工林碳储量显著高于相应同龄封育林的碳储量,D、Z、M人工林碳储量分别为67.75、66.56、121.20 t/hm~2,而D_(CK)、Z_(CK)、M_(CK)封育林仅为49.75、52.89、60.86 t/hm~2。碳储量在乔木层、地被物层、土壤层分配排序因生态系统类型而异,如M:乔木层土壤层地被物层;D和Z:土壤层乔木层地被物层;D_(CK)、Z_(CK)和M_(CK):土壤层地被物层乔木层。此外,M、D、Z乔木层年平均碳储量差异显著,而封育林尚未形成乔木层,其植被碳储量则随封育时间的增加而提高,即M_(CK)Z_(CK)D_(CK)。可见,在中度石漠化山地,植被恢复模式显著影响生态系统碳储量及其分配。人工造林相对于封山育林更能快速促进植被恢复、形成乔木林,从而提高生态系统碳储量。

Effect of vegetation restoration patterns on the carbon storage in a rocky desertification ecosystem

To explore the responses of carbon storage to different vegetation restoration patterns in a rocky desertification ecosystem in Tiandeng County, Guangxi, we selected pure plantations of Dendrocalamus minor (D) and Zenia insignis (Z), a mixed plantation (M) of Z, Buerretiodendron hsienmu (B) and Acrocarpus fraxinifolius (A), as well as their corresponding closed forests (D_CK, Z_CK, M_CK) with same ages to determine the carbon storage. Our results showed that the carbon storages of pure and mixed plantations were significantly higher than those of the corresponding closed forests, (P < 0.05), since the carbon storages of D, Z, and M plantations were 67.75, 66.56, and 121.20 t/hm², seperately, whereas those of D_CK, Z_CK, and M_CK were only 49.75, 52.89, and 60.86 t/hm², respectively. The orders of carbon storage in the layers of tree, ground cover, and soil varied with the ecosystem types. For example, in M:tree layer > soil layer > ground cover layer; in D and Z plantations:soil layer > tree layer > ground cover layer; in D_CK, Z_CK, and M_CK: soil layer > ground cover layer > tree layer. Additionally, the annual average carbon storage of the tree layer was significantly different among M, D, and Z (P < 0.05). However, the enclosed forests did not form arboreal forest and the carbon storage of vegetation increased with enclosure time (M_CK > Z_CK > D_CK). This study suggests that different vegetation restoration patterns can significantly affect the carbon storage and its allocation in the moderate rocky desertification ecosystem, and afforestation is a more effective way to improve the vegetation restoration, form arboreal forests, and further increase the ecosystem carbon storage, compared to the closed forest.