透光抚育对长白山“栽针保阔”红松林土壤碳储量影响
Effect of liberation cutting on the soil carbon storage of a Korean pine forest restored by planting conifers and reserving broad-leaved trees in Changbai Mountains of China.
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摘要: 运用采伐试验方法,研究上层透光抚育(对照为栽针未采伐、轻度透光抚育(25%)、中度透光抚育(50%)、强度透光抚育(75%)、全透光(100%), 透光抚育强度是指蓄积比例)对长白山中期(33年生)“栽针保阔”红松林土壤碳储量及凋落物碳储量的影响。结果表明: 透光抚育对长白山中期“栽针保阔”红松林的土壤密度((0.83±0.02)~(1.15±0.03)g/cm3)与土壤碳含量((43.36±1.60)~(70.26±1.94)g/kg)具有影响。中度透光抚育显著降低了其土壤密度(8.4%,P0.05),但显著提高了其土壤碳含量(14.9%,P0.05);强度透光抚育与全透光显著提高了土壤密度(23.3%和27.1%,P0.05),但也显著降低了土壤碳含量(23.7%和29.1%,P0.05);而轻度透光抚育对土壤密度与土壤碳含量均无显著影响。透光抚育对长白山中期“栽针保阔”红松林的土壤碳储量((13.12±1.57)~(23.46±2.03) kg/m2)产生了较大的影响;其中,中度透光抚育使其土壤碳储量显著提高了12.8%(P0.05),强度透光抚育与全透光使其显著降低了29.9%和36.9%(P0.05),而轻度透光抚育对其并无显著影响。透光抚育对于其凋落物碳储量((2.13±0.39)~(2.82±0.37) t/hm2)的影响相对较大;轻、中度透光抚育较对照提高了8.1%和19.5%,但仅有中度透光抚育提高显著(P0.05),强度透光抚育与全透光样地较对照样地降低了3.8%和9.8%,仅有全透光降低显著(P0.05)。因此,中度透光抚育能够提高中期“栽针保阔”红松林的土壤碳储量及凋落物碳储量,强度透光抚育与全透光则会降低其土壤碳储量(皆伐也会降低其凋落物碳储量),故从维持或提高“栽针保阔”红松林土壤碳储量考虑,采取中低度透光抚育方式比较适宜。Abstract: We studied the effect of liberation cutting on the soil carbon storage and the litter carbon storage of a mid-term (33-year-old) Korean pine forest which was restored by planting conifers and reserving broad-leaved trees by using crown thinning control test method in Changbai Mountains of China. Five levels of cutting intensity were applied, namely, non-cutting (control), mild liberation cutting (25%), moderate liberation cutting (50%), heavy liberation cutting (75%), and clear cutting (100%) (cutting intensity refers to volume percentage). The main research results were as follows. The liberation cutting had certain effects on the soil bulk density ((0.83±0.02)-(1.15±0.03)g/cm3) and the soil carbon concentration ((43.36±1.60)-(70.26±1.94) g/kg) of the Korean pine forest. Compared to the control, moderate liberation cutting decreased the soil bulk density by 8.4% (P0.05), but increased the soil carbon concentration by 14.9% (P0.05). Heavy liberation cutting and clear cutting increased the soil bulk density by 23.3% and 27.1% (P0.05), and degraded the soil carbon concentration by 23.7% and 29.1%, respectively (P0.05). Mild liberation cutting had no significant effect on the two parameters. The liberation cutting had great effect on the soil carbon storage ((13.12±1.57)-(23.46±2.03) kg/m2) of the Korean pine forest. Compared to the control, moderate liberation cutting led to the increase of soil carbon storage by 12.8% (P0.05), while heavy liberation cutting and clear cutting lowered it by 29.9% and 36.9%, respectively (P0.05). Mild liberation cutting had no significant effect on it. The liberation cutting had remarkable effect on the litter carbon storage( (2.13±0.39)-(2.82±0.37) t/ha) of the Korean pine forest. Moderate liberation cutting resulted in the increase of the litter carbon storage by 19.5% (P0.05) compared to the control, while clear cutting reduced it by 9.8% (P0.05). In summary, moderate liberation cutting could increase the soil carbon storage and litter carbon storage of the mid-term Korean pine forest in Changbai Mountains, while heavy liberation cutting and clear cutting would lead to soil carbon storage reducing (the latter also results in the reduction of litter carbon storage). Therefore, mild and moderate liberation cutting should be adopted to maintain or improve the soil carbon sinks for the Korean pine forests.