Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, Vic., 3125, Australia; Institute for Applied Ecology, University of Canberra, Bruce, ACT, 2617, Australia.
Glob Chang Biol. 2015 Apr;21(4):1552-66. doi: 10.1111/gcb.12746. Epub 2014 Oct 31.
Reforestation has large potential for mitigating climate change through carbon sequestration. Native mixed-species plantings have a higher potential to reverse biodiversity loss than do plantations of production species, but there are few data on their capacity to store carbon. A chronosequence (5-45 years) of 36 native mixed-species plantings, paired with adjacent pastures, was measured to investigate changes to stocks among C pools following reforestation of agricultural land in the medium rainfall zone (400-800 mm yr(-1)) of temperate Australia. These mixed-species plantings accumulated 3.09 ± 0.85 t C ha(-1) yr(-1) in aboveground biomass and 0.18 ± 0.05 t C ha(-1) yr(-1) in plant litter, reaching amounts comparable to those measured in remnant woodlands by 20 years and 36 years after reforestation respectively. Soil C was slower to increase, with increases seen only after 45 years, at which time stocks had not reached the amounts found in remnant woodlands. The amount of trees (tree density and basal area) was positively associated with the accumulation of carbon in aboveground biomass and litter. In contrast, changes to soil C were most strongly related to the productivity of the location (a forest productivity index and soil N content in the adjacent pasture). At 30 years, native mixed-species plantings had increased the stability of soil C stocks, with higher amounts of recalcitrant C and higher C:N ratios than their adjacent pastures. Reforestation with native mixed-species plantings did not significantly change the availability of macronutrients (N, K, Ca, Mg, P, and S) or micronutrients (Fe, B, Mn, Zn, and Cu), content of plant toxins (Al, Si), acidity, or salinity (Na, electrical conductivity) in the soil. In this medium rainfall area, native mixed-species plantings provided comparable rates of C sequestration to local production species, with the probable additional benefit of providing better quality habitat for native biota. These results demonstrate that reforestation using native mixed-species plantings is an effective alternative for carbon sequestration to standard monocultures of production species in medium rainfall areas of temperate continental climates, where they can effectively store C, convert C into stable pools and provide greater benefits for biodiversity.
造林通过碳固存具有很大的缓解气候变化的潜力。与生产物种的人工林相比，乡土混交种种植具有更高的逆转生物多样性丧失的潜力，但关于其储存碳的能力的数据很少。在中降雨区（400-800 毫米 yr(-1))，对农业土地进行再造林后，对 36 个乡土混交种种植园（5-45 年）的时间序列进行了测量，以调查 C 库中碳储量的变化。这些混交种种植园在地上生物量中积累了 3.09 ± 0.85 t C ha(-1) yr(-1)，在植物凋落物中积累了 0.18 ± 0.05 t C ha(-1) yr(-1)，达到了与再造林后 20 年和 36 年分别测量的残余林地相当的水平。土壤 C 的增加较慢，仅在 45 年后才出现增加，此时储量尚未达到残余林地的水平。树木数量（树木密度和基面积）与地上生物量和凋落物中碳的积累呈正相关。相比之下，土壤 C 的变化与地点的生产力（森林生产力指数和相邻牧场上的土壤 N 含量）关系最密切。在 30 年时，乡土混交种种植园增加了土壤 C 储量的稳定性，具有更高的难降解碳含量和更高的 C:N 比，比相邻的牧场高。用乡土混交种进行再造林并没有显著改变土壤中大量营养元素（N、K、Ca、Mg、P 和 S）或微量元素（Fe、B、Mn、Zn 和 Cu）的有效性、植物毒素（Al、Si）含量、酸度或盐度（Na、电导率）。在这个中降雨区，乡土混交种种植园提供了与当地生产物种相当的碳封存速率，可能还有额外的好处，为本地生物群提供了更好质量的栖息地。这些结果表明，在中降雨的温带大陆气候区，用乡土混交种进行再造林是标准生产物种单一栽培的有效替代方案，因为它们可以有效地储存碳，将碳转化为稳定的库，并为生物多样性提供更大的好处。
