Natural seedling regeneration and tree establishment are affected by various environmental factors.In this study,we established eight,eight,six,and four independent forest stands(each stand was further divided into fi...Natural seedling regeneration and tree establishment are affected by various environmental factors.In this study,we established eight,eight,six,and four independent forest stands(each stand was further divided into five subplots) respectively based on the altitudinal gradient,stand density,slope location,and slope aspect to investigate the effects of environmental factors on tree seedling regeneration in a pine-oak mixed forest.The results indicated that the seedling density was significantly higher at altitudes of 1,283 m to 1,665 m,whereas the sapling density did not differ with altitudes.The seedling and sapling density decreased significantly at 1,835 m.The seedling densities on the upper slopes were much higher than those on the middle and lower slopes,whereas the sapling density had no difference.The sapling density decreased gradually from the southwest(20°-75°) whereas it increased on the shady slopes to the northeast(40°).The seedling density increased from southwest(20°) to northeast(40°).The seedling and sapling densities increased with the stand density(850 trees ha-1to 1,525 trees ha-1) whereas the sapling density was significantly lower in stands(1,900 trees ha-1).Principal components analysis showed that the slope aspect and stand density had more important roles in tree regeneration in this study region compared with the other two factors.Therefore,our findings suggest that it will be beneficial to keep stands at a moderate density on shady slopes.Appropriate thinning of higher density stands is also expected to promote the natural regeneration of pine-oak mixed forest.展开更多
This review summarizes the current state of knowledge on pine and oak forest dynamics in the midmontane central Himalayan forest and the ecosystem services associated with these vegetation types. Forest ecosystems pla...This review summarizes the current state of knowledge on pine and oak forest dynamics in the midmontane central Himalayan forest and the ecosystem services associated with these vegetation types. Forest ecosystems play a crucial role in the livelihood of the central Himalayas as well as the adjacent plains, providing a number of tangible and intangible ecosystem services, at each stage of succession. The successional sequence starts from warm temperate grasslands, followed by early successional pine forests, mid-successional pine-oak mixed forests and eventually culminating in a late successional oak community. This successional sequence is considerably influenced by disturbances like fire, grazing, and lopping, which maintain the vegetation types in their current form and can act as potential drivers of change. Fire and grazing in grasslands and pine forests inhibit the successional process by hindering the establishment of pioneer and late successional species, respectively. Potential land-cover changes with forest succession can lead to changes in ecosystem services supply. We found that the number of ecosystem services associated with these vegetation types increase from early to late successional community. Current management approaches fail to include the dynamic nature of vegetation, which is essential for maintenance of ecosystem service supply. In conclusion, the trade-offs between ES of global （biodiversity and carbon） and local importance （fuel wood and fodder） have to be examined carefully in order to have effective conservation and management plans for the region.展开更多
土壤生态化学计量比是表征土壤内部养分循环及对植物养分供应状况的重要指标。通过在秦岭中段海拔 1 100 1 900 m 范围内油松(Pinus tabuliformis) 锐齿槲栎(Quercus aliena var. acuteserrata)混交林密集分布的区域设置 23 个调查样地,...土壤生态化学计量比是表征土壤内部养分循环及对植物养分供应状况的重要指标。通过在秦岭中段海拔 1 100 1 900 m 范围内油松(Pinus tabuliformis) 锐齿槲栎(Quercus aliena var. acuteserrata)混交林密集分布的区域设置 23 个调查样地,分 0 20、20 40 和 40 60 cm 3 个土层采取样地土壤样品进行测定,分析不同海拔、不同土层之间土壤 C、N、P 化学计量比的差异,旨在阐明秦岭松栎林土壤 C、N、P 生态化学计量特征对海拔梯度的响应规律,为揭示森林土壤养分限制因素、林地土壤质量评价及秦岭生态系统的保护等提供基础。结果显示:(1)土壤总有机 C、总 N 和总 P 的平均含量分别为 23.723、1.641 和 1.039 g kg 1,随着海拔增加,土壤整体的总 C、总 N 呈上升趋势,而总 P 无明显变化;(2)土壤 C N、C P、N P 的均值分别为 14.906、24.081 和 1.657,随着海拔增加,土壤整体的 C N 呈“先上升 后下降”、N P 呈“先下降 后上升”趋势,C P 无明显变化;(3)0 20 cm 土层的 C P、N P 均显著高于 20 40 cm 和 40 60 cm土层,而不同土层的 C N 之间无显著性差异,且土壤 C、N 之间的正向相关性远高于 C、P 和 N、P;(4)在 20 40 cm土层中,海拔 1 300 1 500 m 处的土壤 C N 较高,而海拔 1 100 1 300 m 处的土壤 N P 较高;在 40 60 cm 土层中,海拔1 300 1 500 m 处的 N P 显著低于 1 100 1 300 m 和 1 700 1 900 m 海拔段。该研究表明,秦岭松栎混交林土壤的 C、N、P含量及其化学计量比沿海拔梯度发生了较为明显的变化,适量增施氮肥有助于缓解林地土壤 N 的限制性作用,且应更加重视高海拔区域的土壤保育工作。展开更多
基金funded by the Special Research Program for Public-Welfare Forestry of State Forestry Administration of China (Grant No. 20100400206)National Natural Science Funds of China (Grant No. 31070570)CFERN & GENE Award Funds on Ecological Paper
文摘Natural seedling regeneration and tree establishment are affected by various environmental factors.In this study,we established eight,eight,six,and four independent forest stands(each stand was further divided into five subplots) respectively based on the altitudinal gradient,stand density,slope location,and slope aspect to investigate the effects of environmental factors on tree seedling regeneration in a pine-oak mixed forest.The results indicated that the seedling density was significantly higher at altitudes of 1,283 m to 1,665 m,whereas the sapling density did not differ with altitudes.The seedling and sapling density decreased significantly at 1,835 m.The seedling densities on the upper slopes were much higher than those on the middle and lower slopes,whereas the sapling density had no difference.The sapling density decreased gradually from the southwest(20°-75°) whereas it increased on the shady slopes to the northeast(40°).The seedling density increased from southwest(20°) to northeast(40°).The seedling and sapling densities increased with the stand density(850 trees ha-1to 1,525 trees ha-1) whereas the sapling density was significantly lower in stands(1,900 trees ha-1).Principal components analysis showed that the slope aspect and stand density had more important roles in tree regeneration in this study region compared with the other two factors.Therefore,our findings suggest that it will be beneficial to keep stands at a moderate density on shady slopes.Appropriate thinning of higher density stands is also expected to promote the natural regeneration of pine-oak mixed forest.
文摘This review summarizes the current state of knowledge on pine and oak forest dynamics in the midmontane central Himalayan forest and the ecosystem services associated with these vegetation types. Forest ecosystems play a crucial role in the livelihood of the central Himalayas as well as the adjacent plains, providing a number of tangible and intangible ecosystem services, at each stage of succession. The successional sequence starts from warm temperate grasslands, followed by early successional pine forests, mid-successional pine-oak mixed forests and eventually culminating in a late successional oak community. This successional sequence is considerably influenced by disturbances like fire, grazing, and lopping, which maintain the vegetation types in their current form and can act as potential drivers of change. Fire and grazing in grasslands and pine forests inhibit the successional process by hindering the establishment of pioneer and late successional species, respectively. Potential land-cover changes with forest succession can lead to changes in ecosystem services supply. We found that the number of ecosystem services associated with these vegetation types increase from early to late successional community. Current management approaches fail to include the dynamic nature of vegetation, which is essential for maintenance of ecosystem service supply. In conclusion, the trade-offs between ES of global （biodiversity and carbon） and local importance （fuel wood and fodder） have to be examined carefully in order to have effective conservation and management plans for the region.
文摘土壤生态化学计量比是表征土壤内部养分循环及对植物养分供应状况的重要指标。通过在秦岭中段海拔 1 100 1 900 m 范围内油松(Pinus tabuliformis) 锐齿槲栎(Quercus aliena var. acuteserrata)混交林密集分布的区域设置 23 个调查样地,分 0 20、20 40 和 40 60 cm 3 个土层采取样地土壤样品进行测定,分析不同海拔、不同土层之间土壤 C、N、P 化学计量比的差异,旨在阐明秦岭松栎林土壤 C、N、P 生态化学计量特征对海拔梯度的响应规律,为揭示森林土壤养分限制因素、林地土壤质量评价及秦岭生态系统的保护等提供基础。结果显示:(1)土壤总有机 C、总 N 和总 P 的平均含量分别为 23.723、1.641 和 1.039 g kg 1,随着海拔增加,土壤整体的总 C、总 N 呈上升趋势,而总 P 无明显变化;(2)土壤 C N、C P、N P 的均值分别为 14.906、24.081 和 1.657,随着海拔增加,土壤整体的 C N 呈“先上升 后下降”、N P 呈“先下降 后上升”趋势,C P 无明显变化;(3)0 20 cm 土层的 C P、N P 均显著高于 20 40 cm 和 40 60 cm土层,而不同土层的 C N 之间无显著性差异,且土壤 C、N 之间的正向相关性远高于 C、P 和 N、P;(4)在 20 40 cm土层中,海拔 1 300 1 500 m 处的土壤 C N 较高,而海拔 1 100 1 300 m 处的土壤 N P 较高;在 40 60 cm 土层中,海拔1 300 1 500 m 处的 N P 显著低于 1 100 1 300 m 和 1 700 1 900 m 海拔段。该研究表明,秦岭松栎混交林土壤的 C、N、P含量及其化学计量比沿海拔梯度发生了较为明显的变化,适量增施氮肥有助于缓解林地土壤 N 的限制性作用,且应更加重视高海拔区域的土壤保育工作。
