杉木人工林阔叶化改造对林分碳密度的影响

Effect of Transforming Pure Cunninghamia lanceolate Plantation to mixed Forest with Broad-leaf Tree Species on Organic Carbon Density

杉木Cunninghamia lanceolata人工林连栽导致生产力下降,将杉木二代林改造为杉阔混交林对提高林分生产力和碳汇能力具有重要意义。本文在杉木二代林内分别引入光皮桦Betula luminifera、木荷Schima superba和厚朴Magnolia officinalis,构建杉阔混交林,分析了各林分乔木层、林下植被层、凋落物层和土壤层有机碳密度变化。结果表明:杉木+木荷、杉木+厚朴混交林乔木层碳密度与杉木纯林接近,但杉木+光皮桦比杉木纯林乔木层碳密度减少了25.8%。3种杉阔混交林与杉木纯林之间林下植被碳密度没有差异,但凋落物碳密度均低于杉木纯林。杉木+光皮桦、杉木+木荷和杉木+厚朴混交林0~50 cm土层土壤有机碳密度分别比杉木纯林增加了5.9%、8.6%和21.7%。相对于杉木纯林,杉木+木荷和杉木+厚朴混交林林分总碳密度分别增加了5.7%和15.3%,而杉木+光皮桦林林分总碳密度则减少了6.1%。因此,树种组成显著影响杉阔混交林林分碳密度及其分配特征,选择适宜的树种进行杉木二代林阔叶化改造是提高林分固碳潜力的关键。

In Febuary 2007,transformation was carried out on cutting area of pure the first generation of Cunninghamia lanceolata plantation in Kaihua,Zhejiang Province.Afforestations were implemented on different sample plots namely of pure C.lanceolata suckers(CK),2-year container seedlings of Betula luminifera,Schima superba and Houpoea officinalis with C.lanceolata suckers.In November 2022,investigation was made on different sample plots,with DBH,height and stand density.Biomass of sample trees in each plots,understorey vegetation was determined and soil organic carbon and soil bulk density was detected.The results showed that the organic carbon density of arbor layer in C.lanceolata suckers+S.superba and C.lanceolata suckers+H.officinalis was close to that in the control,but that in C.lanceolata suckers+B.luminifera was 25.8%lower than that in the control.There was no difference of organic carbon density of understory vegetation between the three mixed plantations and the control,but the organic carbon density of litter was lower than that of the control.The soil organic carbon density in the 0-50 cm soil layer of the three mixed plantations was 5.9%,8.6%and 21.7%higher than that of the control.Compared with the control,the total organic carbon density of mixed C.lanceolata suckers+S.superba and C.lanceolata suckers+M.officinalis plantations increased by 5.7%and 15.3%,while that of C.lanceolata suckers+B.luminifera plantation decreased by 6.1%.