目标树经营初期对马尾松人工林碳贮量的影响

【目的】大气温室气体浓度增加导致全球气候变暖日益受到重视,保护现有人工林碳贮量以及开展科学的森林经营活动,已成为改善林分结构,增强陆地碳汇的重要措施。【方法】以川东华蓥33年马尾松人工林为对象,采用3种目标树密度(H1.100;H2.150;H3.200株/hm²)经营方式,研究目标树经营后马尾松人工林碳贮量变化。 【结果】与对照林分相比较,目标树经营后乔木层(各器官)、林下层贮量变化差异显著(P<0.05),而不同处理间土壤层碳贮量变化差异不显著(P>0.05);目标树经营后乔木层碳贮量生长量分别为15.65%、18.70%、16.59%,均高于HCK(对照林)的13.4%;目标树干、枝、叶、根和全株碳贮量生长量平均值较一般树高出66.04%、51.25%、52.09%、48.81%和38.67%,各器官碳贮量大小顺序为树干>根系>树枝>树叶;林下层碳贮量变化除草本层为H2>H3>H1>HCK,其余层次皆为H3>H2>H1>HCK;土壤层碳贮量为244.86 t/hm²,占林分总碳贮量76.44%,但土壤表层(0~5cm)碳贮量占土壤层(0~40 cm)的45.52%,并呈现随着土壤深度增加而显著减少的趋势;马尾松林碳库空间分布为土壤层(0~40 cm)>乔木层>灌木层>草本层>枯枝落叶层>粗木残体层。【结论】目标树经营可提高马尾松人工林碳贮量,且经营密度为150株/hm²的马尾松林碳贮量最高。

Early effect of target tree management on carbon storage in Pinus massoniana plantations

【Objective】 Increasing atmospheric greenhouse gas concentrations have led to an increase in the attention toward the causes and effects of global warming. Protecting existing plantation carbon storage and carrying out scientific forest management activities have become important measures to improve the structure of forest stands and enhance terrestrial carbon sinks. 【Method】 A 33-year-old Pinus massoniana plantation in Huaying City, eastern Sichuan, China, was used to analyze the variations of Pinus massoniana carbon storage on the basis of target tree density. 【Result】 We adopted a target tree density of 100(H1), 150(H2) and 200(H3) plants/hm^2 for our study. The results showed that, compared with the control forest(HCK), the storage changes of the arbor layer(organs) and the understory of the target tree were significantly different(P < 0.05) but that there was no significant difference in soil layer carbon storage between different treatments(P > 0.05). The carbon storage growth of the arbor layer was 15.65%, 18.70% and 16.59% for H1, H2 and H3, respectively, which was higher than 13.4% for HCK. The average carbon storage growth of stem, branch, leaf, root and whole tree in the target tree were higher than 66.04%, 51.25%, 52.09%, 48.81% and 38.67% for HCK;these values higher than that of ordinary trees. The range of carbon storage in each organ was trunk > root > branch > leaf. The carbon storage in the herb layer was H2>H3>H1>HCK, and the rest of them were H3>H2>H1>HCK. Carbon storage of the soil layer was 244.86 t/hm^2 and accounted for 76.44% of the total carbon storage in the plantation, but the carbon storage in the soil surface(0-5 cm) accounted for 45.52% of the soil layer(0-40 cm). A trend of significant reduction in carbon storage was observed with an increase in soil depth. The spatial distribution of the carbon pool of Pinus massoniana plantation was soil layer(0-40 cm) > arbor layer > shrub layer > herb layer > litter layer > crude wood residue layer.【Conclusion】 Target tree management can increase the carbon storage of Pinus massoniana plantations, and the carbon storage in Pinus massoniana plantations with a density of 150 target trees per hectare was the highest.