抚育间伐对小兴安岭天然针阔混交林碳储量的影响

在小兴安岭地区带岭林业实验局东方红林场天然林试验区,设置6块样地,对天然针阔混交次生林进行不同强度(10%、15%、20%、25%、30%、35%)的抚育间伐;采用平均标准木法取样、实验室重铬酸钾法测定林木碳质量分数,分析不同间伐强度对乔木层地上部分生物量及碳储量的影响。结果表明:随着间伐强度的增加,乔木层地上部分生物量、碳储量整体呈先增加再减小趋势,但间伐8 a内各间伐生物量、碳储量均显著少于对照。伐后1~4 a,间伐强度20%,乔木层碳储量增长率、增长量均高于对照;间伐后1~4 a内,间伐强度20%,乔木层碳储量的恢复能力最强。间伐后5~8 a,高度间伐(间伐强度30%、35%)碳储量恢复能力最弱;间伐8 a后,各间伐强度(10%、15%、20%、25%、30%、35%)的碳储量,分别为74.93±3.42、86.96±7.31、99.24±2.43、93.64±6.68、85.23±2.11、79.54±3.38 t/hm2,林木各器官碳储量差异显著,从大到小依次为树干、树枝、树叶;间伐8 a后,各间伐树干碳储量所占比例比对照所占比例增加-0.04%~12.27%,在间伐强度为20%时树干碳储量比例最高,说明间伐强度20%有利于小兴安岭天然针阔混交林树干碳储量的累积及单株林木质量的提高。总体看,短期间伐(4 a内)利于20%间伐乔木层碳储量的迅速积累,8 a内各间伐仍处于乔木层地上部分碳储量低于对照的恢复期。

Effects of Tending and Thinning on Partial Above-ground Carbon Storage of Natural Coniferous and Broad- leaved Mixed Forest in Xiaoxing'an Mountains

In the natural forest experimental area of Dongfanghong Forest Farm of Dailing Forestry Experimental Bureau in Xiaoxing’an Mountains, six sample plots were set up to carry out tending and thinning of natural coniferous and broad-leaved mixed secondary forest with different intensities(10%, 15%, 20%, 25%, 30% and 35%);the average standard wood sampling method was used to sample, and potassium dichromate method was used to determine the carbon content of trees and its impact on carbon storage. With the increase of thinning intensity, the aboveground biomass and carbon storage of tree layer increased first and then decreased, but the biomass and carbon storage of each thinning within 8 a were significantly less than that of the control. In 1-4 a after thinning, the thinning intensity was 20%, and the growth rate and growth amount of carbon storage in tree layer were higher than that of control;within 1-4 a after thinning, thinning intensity was 20%, and the recovery ability of carbon storage in tree layer was the strongest. After 5-8 a thinning, the carbon storage recovery ability of high thinning intensity(30% and 35%) was the weakest. After 8-a thinning, the carbon storage of each thinning intensity(10%, 15%, 20%, 25%, 30% and 35%) was 74.93±3.42, 86.96±7.31, 99.24±2.43, 93.64±6.68, 85.23±2.11, 79.54±3.38 t/hm~2, respectively. After 8-a thinning, the proportion of dry carbon storage of each inter cutting tree increased by-0.04%-12.27% compared with the control, and the proportion of stem carbon storage was the highest when the thinning intensity was 20%, indicating that 20% thinning intensity was beneficial to the accumulation of stem carbon storage and the improvement of individual tree quality of natural coniferous and broad-leaved mixed forest in Xiaoxing’an Mountains. On the whole, short-term thinning(within 4 a) was beneficial to the rapid accumulation of carbon storage in 20% thinning tree layer, and the carbon storage of aboveground part of tree layer was still lower than that of control in 8 a.