透光抚育对长白山"栽针保阔"红松林土壤碳储量影响

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。 

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.

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% (P<0. 05), but increased the soil carbon concentration by 14. 9% ( P<0. 05 ) . Heavy liberation cutting and clear cutting increased the soil bulk density by 23. 3% and 27. 1% ( P<0. 05 ) , and degraded the soil carbon concentration by 23. 7% and 29. 1%, respectively ( P<0. 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% ( P<0. 05 ) , while heavy liberation cutting and clear cutting lowered it by 29. 9% and 36. 9%, respectively ( P<0. 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% ( P<0. 05 ) compared to the control, while clear cutting reduced it by 9. 8% (P<0. 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.