矿区废弃地不同林龄栾树人工林生物量和碳储量变化趋势

Abstract

对湘潭锰矿区废弃地植被恢复区的3年生、5年生和9年生栾树林，进行了不同时间序列栾树林生物量和碳储量的时空变化研究。结果表明：随着林龄的增长，林木和各器官生物量增加，树干生物量所占比例逐渐增大，林下植被层生物量随林龄增长而增加，且以草本植被为主；不同林龄栾树人工林乔木层碳含量在0.51-0.53gC/g之间，并高于林下植被层碳含量；不同林龄林地土壤层碳含量变化范围为0.01-0.03gC/g，同一林龄不同深度土层碳含量没有显著差异，相同深度不同林龄土层碳含量存在差异；3年生、5年生和9年生栾树碳储量分别为：1.66、18.32和49.87t/hm²，随林龄增长而增加，其中树干碳储量贡献率最大，所占比例由3年生的27.71%增长到9年生的43.43%；不同林龄栾树林生态系统总碳储量分别为77.76、101.63和149.86t/hm²，其中土壤层碳储量变化范围为76.09-99.93t/hm²，占总储量的66.68%-97.85%，死地被物层碳储量为0.01-0.04t/hm²，占总储量0.001%-0.02%，植被层碳储量为1.67-49.89t/hm²，占总碳储量的2.15%-33.29%，植被层中乔木层为1.66-49.87t/hm²，占植被层碳储量的99%以上。各林龄栾树林生态系统碳储量空间分布序列为土壤层>植被层>死地被物层。研究结果可为我国矿区植被恢复地的森林资源和碳汇管理提供科学依据。;Over the past decade, <em>Koelreuteria paniclata</em> was introduced in manganese mine wastelands in central southern China as a suitable plant species in order to remove metals from the contaminated soils. In this study, we examined changes in biomass and carbon storage in 3 <em>K. paniclata </em>plantations at 3-, 5-and 9-year old stands in a Mn mining wasteland. We measured biomass and carbon concentrations in various plant organs and soil depths and estimated total carbon storage in the forests to gain an understanding of the dynamics of biomass and carbon in the plantation ecosystems since phytoremediation.<br> The result showed that: (1) The different tree organs biomass, total tree biomass increased with aged stands, and the proportion of stem biomass in the total tree biomass increased with increasing of stand ages. The biomass in undertorey layer increased with aging stands with dominant component of herbaceous vegetation; (2) The carbon content ranged from 0.51 gC/g to 0.53 gC/g, in overstorey layer and was higher than that in understorey layer. The carbon content in soil layer ranged from 0.01 gC/g to 0.03gC/g, and significant differences of carbon content were found at the same soil depth in different aged stands; (3) The biomass carbon storage was 1.66、18.32 and 49.87 t/hm² in 3-,5-and 9-year old plantations, respectively. The stem was a dominant component of the tree biomass carbon storage, which accounted for the larger part of the total biomass carbon storage, from 27.71% at 3-year old stands to 43.43% at 9-year old stands; (4) The total carbon storage was 77.76、101.63 and 149.86 t/hm² in 3-,5-and 9-year old <em>K. paniclata</em> plantation ecosystems respectively. The carbon storage in soils ranged from 76.09 t/hm² to 99.93 t/hm², which accounted for 66.68%-97.85% of the total carbon in the ecosystems. The carbon storage in litter layer ranged from 0.01 to 0.04 t/hm², which accounted for 0.001%-0.02% of the total carbon storage in the plantation ecosystems. (5) The carbon storage in vegetation layer ranged from 1.67 to 49.89 t/hm² in the aging stands, accounting for 2.15% to 33.29% of the total carbon storage in these forested ecosystems. The carbon storage in different components of the aged <em>K. paniclata</em> plantation ecosystems was in order as soil layer > vegetation layer > litter layer. Our results may provide scientific references for sustainable forest resources management and carbon sink forest development in vegetation restoration of mining wastelands.