【目的】针对川中丘陵区普遍存在的柏木人工林密度过大、木材生产力低、林下灌草盖度低和天然更新不良等问题，开展生态疏伐试验，探讨间伐强度对林分生长和林下植物的影响，为开展柏木生态经济型防护林的营林活动提供参考。【方法】以2...【目的】针对川中丘陵区普遍存在的柏木人工林密度过大、木材生产力低、林下灌草盖度低和天然更新不良等问题，开展生态疏伐试验，探讨间伐强度对林分生长和林下植物的影响，为开展柏木生态经济型防护林的营林活动提供参考。【方法】以25年生柏木人工林为研究对象，采用随机区组方法，设置4种间伐强度（20%～25%，15%～20%，10%～15%和对照）的处理，观察林分胸径、树高、蓄积量、生物多样性和天然更新幼苗数量，探讨间伐强度对其影响。【结果】不同强度间伐5年后林分平均胸径和胸径连年生长量在各处理之间均存在显著差异，胸径生长量随间伐强度加大而增加；平均树高以20%～25%间伐强度最大，达10.7 m，但20%～25%间伐强度与15%～20%间伐强度和10%～15%间伐强度之间无显著差异，而树高连年生长量在不同处理之间差异显著；20%～25%，15%～20%和10%～15%不同强度间伐5年后林分蓄积量分别为97.35，93.43和93.19 m3·hm －2，均比对照小，但蓄积连年生长量随间伐强度由高到低分别为6.11，4.58和3.66 m3·hm －2 a －1，均高于对照；20%～25%间伐强度林分的灌木和草本 Simpson 指数分别为0.7695和0.4446，Shannon-Wiener 指数分别为1.7025和0.7690，都比其他处理高；不同间伐强度天然更新幼苗株数仅在苗高5～30 cm 等级存在显著差异，30～50和50～150 cm 的幼苗在不同处理之间差异不明显；评价结果表明，综合得分以20%～25%间伐强度最大，且随间伐强度降低而减小。【结论】间伐后保留木的生长空间和营养空间得到有效改善，林分胸径和树高生长量随间伐强度增大而增加，但不同间伐强度蓄积量差异不显著；适度间伐可提高林下灌木和草本生物多样性指数；林分更新幼苗数量也随着间伐强度的增大而增加；就本研究的4种间伐强度而言，中龄阶段柏木人工林的�展开更多
In 2000, the effect of thinning intensities with five different treatments of 0%(CK), 30%(slight thinning), 48.75%(middle thinning),53.75%(intense thinning) and 65.6%(super intense thinning) on the soil enzyme were ca...In 2000, the effect of thinning intensities with five different treatments of 0%(CK), 30%(slight thinning), 48.75%(middle thinning),53.75%(intense thinning) and 65.6%(super intense thinning) on the soil enzyme were carried out in the 9-year-old aerial seeding Pinus tabulaeformis stands with initial density of 8 000 trees·hm -2 , in QingQuanPu Aerial Seeding Center, Yanqing County of Beijing Municipality. Five years later, the activities of the five soil enzymes such as soil urease, alkaline phosphatase, inertase, catalase and polyphenol oxidase in the different soil layers of A(0～20 cm), B(20～40 cm) and C(40～60 cm) were compared. Moreover, relationships among soil enzymes, soil physiochemical properties and the diversity of the undergrowth were analyzed to prove the availability of using soil enzymes to evaluate the thinning intensities. The results showed that soil catalase varied slightly while the other four soil enzymes decrease with increasing soil depth. And the soil enzymes in the layer A were enhanced distinctly compared with in the layers B and C. Also, the five soil enzymes in the layer A were affected differently by thinning intensities, showing that soil urease and alkaline phosphatase were highest response to slight thinning followed by the middle thinning, opposite to the trend of inertase and polyphenol oxidase. There are significantly positive relationships between soil enzymes and soil physiochemical characteristics and the organic C and total N was more dominant than available K as well as available P. Except soil polyphenol oxidase, the other soil enzymes showed positive relationships with biodiversity of the undergrowth. It was concluded that reasonable thinning intensity was benefit to the development of the undergrowth and so can be to soil enzymes. Generally, when the stand with initial density of 8 000 trees·hm -2 grows up to 9 years old, the reasonable thinning intensity should be about 48.75%.展开更多
文摘【目的】针对川中丘陵区普遍存在的柏木人工林密度过大、木材生产力低、林下灌草盖度低和天然更新不良等问题，开展生态疏伐试验，探讨间伐强度对林分生长和林下植物的影响，为开展柏木生态经济型防护林的营林活动提供参考。【方法】以25年生柏木人工林为研究对象，采用随机区组方法，设置4种间伐强度（20%～25%，15%～20%，10%～15%和对照）的处理，观察林分胸径、树高、蓄积量、生物多样性和天然更新幼苗数量，探讨间伐强度对其影响。【结果】不同强度间伐5年后林分平均胸径和胸径连年生长量在各处理之间均存在显著差异，胸径生长量随间伐强度加大而增加；平均树高以20%～25%间伐强度最大，达10.7 m，但20%～25%间伐强度与15%～20%间伐强度和10%～15%间伐强度之间无显著差异，而树高连年生长量在不同处理之间差异显著；20%～25%，15%～20%和10%～15%不同强度间伐5年后林分蓄积量分别为97.35，93.43和93.19 m3·hm －2，均比对照小，但蓄积连年生长量随间伐强度由高到低分别为6.11，4.58和3.66 m3·hm －2 a －1，均高于对照；20%～25%间伐强度林分的灌木和草本 Simpson 指数分别为0.7695和0.4446，Shannon-Wiener 指数分别为1.7025和0.7690，都比其他处理高；不同间伐强度天然更新幼苗株数仅在苗高5～30 cm 等级存在显著差异，30～50和50～150 cm 的幼苗在不同处理之间差异不明显；评价结果表明，综合得分以20%～25%间伐强度最大，且随间伐强度降低而减小。【结论】间伐后保留木的生长空间和营养空间得到有效改善，林分胸径和树高生长量随间伐强度增大而增加，但不同间伐强度蓄积量差异不显著；适度间伐可提高林下灌木和草本生物多样性指数；林分更新幼苗数量也随着间伐强度的增大而增加；就本研究的4种间伐强度而言，中龄阶段柏木人工林的�
文摘In 2000, the effect of thinning intensities with five different treatments of 0%(CK), 30%(slight thinning), 48.75%(middle thinning),53.75%(intense thinning) and 65.6%(super intense thinning) on the soil enzyme were carried out in the 9-year-old aerial seeding Pinus tabulaeformis stands with initial density of 8 000 trees·hm -2 , in QingQuanPu Aerial Seeding Center, Yanqing County of Beijing Municipality. Five years later, the activities of the five soil enzymes such as soil urease, alkaline phosphatase, inertase, catalase and polyphenol oxidase in the different soil layers of A(0～20 cm), B(20～40 cm) and C(40～60 cm) were compared. Moreover, relationships among soil enzymes, soil physiochemical properties and the diversity of the undergrowth were analyzed to prove the availability of using soil enzymes to evaluate the thinning intensities. The results showed that soil catalase varied slightly while the other four soil enzymes decrease with increasing soil depth. And the soil enzymes in the layer A were enhanced distinctly compared with in the layers B and C. Also, the five soil enzymes in the layer A were affected differently by thinning intensities, showing that soil urease and alkaline phosphatase were highest response to slight thinning followed by the middle thinning, opposite to the trend of inertase and polyphenol oxidase. There are significantly positive relationships between soil enzymes and soil physiochemical characteristics and the organic C and total N was more dominant than available K as well as available P. Except soil polyphenol oxidase, the other soil enzymes showed positive relationships with biodiversity of the undergrowth. It was concluded that reasonable thinning intensity was benefit to the development of the undergrowth and so can be to soil enzymes. Generally, when the stand with initial density of 8 000 trees·hm -2 grows up to 9 years old, the reasonable thinning intensity should be about 48.75%.
