There is a strong link between vegetation and environmental factors.Therefore,to elucidate how the stoichiometric characteristics of plants respond to different habitats,we studied organic carbon(C)and total nitrogen(...There is a strong link between vegetation and environmental factors.Therefore,to elucidate how the stoichiometric characteristics of plants respond to different habitats,we studied organic carbon(C)and total nitrogen(N)stoichiometry characteristics of plants in four different habitats of two different natural Korean pine forests.Three of the habitats(gaps,mounds,and pits)were formed via tree uprooting,whereas an undisturbed site(closed canopies)was used as a control.The followings were our main findings:(1)the organic carbon content of more than half of the 12 picked plants showed significant differences in different habitats.Most of the plants in pit-mound complexes exhibited lower organic carbon contents than plants in gaps and closed canopies;(2)there was no significant differences in the total nitrogen content in 13 of the 25 groups of plant samples;(3)interestingly,the C/N of the sample groups with significant differences in total nitrogen also showed significant differences;(4)there was no significant variations in the stoichiometric characteristics of plants that grew in gaps;however,the variations among plants that grew in pits and mounds were significant;(5)through redundancy analysis(RDA),we find that the main factors effecting the C and N stoichiometric characters of the plants were plants own regulation and the change of photosynthetically active radiation(PAR).In conclusion,the C and N stoichiometric characteristics of plants did not respond to gap formations,but they did strongly respond to pit-mound complex formations.Photosynthetically active radiation was the most important effective factor to plants in the four habitats.展开更多
Snow damage on natural stands is an important problem concerning mountainous forest management.In the present research,the frequency and intensity of heavy snow damage on natural stands and the relationship of damages...Snow damage on natural stands is an important problem concerning mountainous forest management.In the present research,the frequency and intensity of heavy snow damage on natural stands and the relationship of damages with characteristics of trees,stand and topography were studied in mountainous forests of northern Iran.A systematic sampling design was applied to the study area(140 ha),with 122 circular plots.The grid dimension was100 m and each plot area was 1000 m^2.The four types of snow damage to trees include:crown damage(8.6%),stem breakage(5.4%),uprooting(3.2%),and bending(1.4%).The frequency of crown damage grew with an increase inthe diameter at breast height(DBH),while the frequency of stem breakage,uprooting and bending decreased with an increase the DBH.The frequency of crown damage,stem breakage,and total damages was related to tree species(p<0.01).Not all tree species were equally susceptible to snow damage.The amount of damage grew with increasing elevation and slope angle and decreased with increasing soil depth.Young trees(DBH<25 cm)were more susceptible to snow damage than other trees.Snow damage decreased by as the trees in the stand became more mixed in age.The susceptibility of trees to snow damage increased by height and slenderness coefficient.With adequate silvicultural operation,snow damage can be reduced to a minimum level in these natural forests.展开更多
Strong wind events frequently result in creating large areas of windthrow, which causes abrupt environmental changes. Bare soil surfaces within pits and root plates potentially expose soil to erosion. Absence of fores...Strong wind events frequently result in creating large areas of windthrow, which causes abrupt environmental changes. Bare soil surfaces within pits and root plates potentially expose soil to erosion. Absence of forest may alter the dynamics of water circulation. In this study we attempt to answer the question of whether extensive windthrows influence the magnitude of geomorphic processes in 6 small second-to third-order catchments with area ranging from 0.09 km^(2) to 0.8 km^(2). Three of the catchments were significantly affected by a windthrow which occurred in December 2013 in the Polish part of the Tatra Mountains, and the other three catchments were mostly forested and served as control catchments. We mapped the pits created by the windthrow and the linear scars created by salvage logging operations in search of any signs of erosion within them. We also mapped all post-windthrow landslides created in the windthrow-affected catchments. The impact of the windthrow on the fluvial system was investigated by measuring a set of channel characteristics and determining bedload transport intensity using painted tracers in all the windthrow-affected and control catchments. Both pits and linear scars created by harvesting tend to become overgrown by vegetation in the first several years after the windthrow. The only signs of erosion were observed in 10% of the pits located on convergent slopes. During the period from the windthrow event in 2013 until 2019, 5 very small(total area <100 m^(2)) shallow landslides were created. The mean distance of bedload transport was similar(t-test, p=0.05) in most of the windthrow-affected and control catchments. The mapping of channels revealed many cases of root plates fallen into a channel and pits created near a channel. A significant amount of woody debris delivered into the channels influenced the activity of fluvial processes by creating alternating zones of erosion and accumulation.展开更多
In accordance with a proposal put forward by leaders of the US Bureau of Water & Soil Conservation during a meeting with the author on July 20, 1994, this article gives a detailed account of the origin and strateg...In accordance with a proposal put forward by leaders of the US Bureau of Water & Soil Conservation during a meeting with the author on July 20, 1994, this article gives a detailed account of the origin and strategies against flooding scourge in the Yangtze valley, based on the author’s research results achieved from his 15-year-long work in the Institute of Natural Tillage-free Research, Yibin City, Sichuan Province. In addition, the author puts forward suggestions aiming at eliminating the natural calamities and realizing social stability to meet the people’s long-cherished wishes, which should be considered by all government departments responsible for agriculture, forestry and the exploitation of water and other natural resources.展开更多
Tree uprooting is an important process which leads to many geomorphic consequences.Some of the most important are the transport of sediment and mixing of soil.The aim of this article is to make a detailed examination ...Tree uprooting is an important process which leads to many geomorphic consequences.Some of the most important are the transport of sediment and mixing of soil.The aim of this article is to make a detailed examination of the magnitude of sediment transport caused by an extreme windthrow event in three severely affected catchments.Also,a comparison is made of the windthrow event with a mass movement event in the aspect of the magnitude of sediment transport and soil mixing.The study was conducted in three second-to third-order catchments in the Tatra Mountains,where a strong foehn wind event caused extensive windthrow in 2013,and a high-magnitude rainfall event triggered mass movements in 2007.The volume of sediment uplifted by the uprooting event was calculated based on the mapping of root plates using high-resolution(0.04 m)aerial images and measurements of root plate volumes conducted in the field.The volume of sediment transported by shallow landslides was determined based on a Digital Elevation Model(DEM1-m resolution).Windthrows affected 34%,76%,and94%of the area of the investigated catchments.Most of the trees had fallen downslope.The direction of treefall was influenced by the slope aspect and steepness.Root plates and pits covered 1.3%,4.8%,and 5.4%of the area of the catchments.Sediment flux generated by the uprooting event,calculated for the entire area of each investigated catchment ranged from 8.1×10^(–4) to 9.9×10^(–3) m^(3) m^(–1) event^(–1).This was notably lower than the sediment flux generated by the mass movement event(also calculated for the entire area of each catchment),which was 1.8-6.1×10^(–2)m^(3) m^(–1) event^(–1).By contrast,uprooting affected a much larger area than the mass movement event,which underlines its significant role in the mixing of soil.展开更多
为量化典型黑土区主要树种根系构型特征,探究其对固土能力的影响,以该区分布较广的榆叶梅、小叶锦鸡儿、白桦、糖槭、红皮云杉、樟子松单株个体为研究对象,采用全根挖掘和WinRHIZO Pro LA2004分析系统相结合对其根系空间分布、几何形态...为量化典型黑土区主要树种根系构型特征,探究其对固土能力的影响,以该区分布较广的榆叶梅、小叶锦鸡儿、白桦、糖槭、红皮云杉、樟子松单株个体为研究对象,采用全根挖掘和WinRHIZO Pro LA2004分析系统相结合对其根系空间分布、几何形态、分形等特征进行测定,同时采用原位整株根系拉拔的方法量化根系垂直拉拔力。结果表明:榆叶梅以倾斜根为主,小叶锦鸡儿、白桦、糖槭和红皮云杉以水平根为主,樟子松根系在水平和垂直分布上较为均衡;除白桦总根表面积和红皮云杉总根长外,灌木树种总根长、总根表面积显著大于乔木,落叶阔叶乔木总根长、总根表面积显著大于针叶常绿乔木,白桦总根体积显著大于小叶锦鸡儿、糖槭、红皮云杉和樟子松;榆叶梅、小叶锦鸡儿和白桦根系分形维数和分形丰度显著大于红皮云杉和樟子松;榆叶梅、小叶锦鸡儿和糖槭整株根系平均最大垂直拉拔力显著大于白桦、樟子松和红皮云杉。主要受根系总根长、总根表面积和倾斜根数量的影响,榆叶梅、小叶锦鸡儿和糖槭根系表现出较强的固土能力,可作为典型黑土区水土保持植被构建中优先选择的树种。展开更多
基金jointly supported by the Fundamental Research Funds for the Central Universities(2572021DT04)the National Natural Science Foundation of China(NSFC)(31670627,31770656)。
文摘There is a strong link between vegetation and environmental factors.Therefore,to elucidate how the stoichiometric characteristics of plants respond to different habitats,we studied organic carbon(C)and total nitrogen(N)stoichiometry characteristics of plants in four different habitats of two different natural Korean pine forests.Three of the habitats(gaps,mounds,and pits)were formed via tree uprooting,whereas an undisturbed site(closed canopies)was used as a control.The followings were our main findings:(1)the organic carbon content of more than half of the 12 picked plants showed significant differences in different habitats.Most of the plants in pit-mound complexes exhibited lower organic carbon contents than plants in gaps and closed canopies;(2)there was no significant differences in the total nitrogen content in 13 of the 25 groups of plant samples;(3)interestingly,the C/N of the sample groups with significant differences in total nitrogen also showed significant differences;(4)there was no significant variations in the stoichiometric characteristics of plants that grew in gaps;however,the variations among plants that grew in pits and mounds were significant;(5)through redundancy analysis(RDA),we find that the main factors effecting the C and N stoichiometric characters of the plants were plants own regulation and the change of photosynthetically active radiation(PAR).In conclusion,the C and N stoichiometric characteristics of plants did not respond to gap formations,but they did strongly respond to pit-mound complex formations.Photosynthetically active radiation was the most important effective factor to plants in the four habitats.
文摘Snow damage on natural stands is an important problem concerning mountainous forest management.In the present research,the frequency and intensity of heavy snow damage on natural stands and the relationship of damages with characteristics of trees,stand and topography were studied in mountainous forests of northern Iran.A systematic sampling design was applied to the study area(140 ha),with 122 circular plots.The grid dimension was100 m and each plot area was 1000 m^2.The four types of snow damage to trees include:crown damage(8.6%),stem breakage(5.4%),uprooting(3.2%),and bending(1.4%).The frequency of crown damage grew with an increase inthe diameter at breast height(DBH),while the frequency of stem breakage,uprooting and bending decreased with an increase the DBH.The frequency of crown damage,stem breakage,and total damages was related to tree species(p<0.01).Not all tree species were equally susceptible to snow damage.The amount of damage grew with increasing elevation and slope angle and decreased with increasing soil depth.Young trees(DBH<25 cm)were more susceptible to snow damage than other trees.Snow damage decreased by as the trees in the stand became more mixed in age.The susceptibility of trees to snow damage increased by height and slenderness coefficient.With adequate silvicultural operation,snow damage can be reduced to a minimum level in these natural forests.
基金This research is part of the project“Impact of extensive windthrow areas on the dynamics of slopefluvial system”funded by the National Science Centre,Poland(DS,grant No.UMO-2017/27/N/ST10/00802)Mapping scars created by wood transport in 2016 and recording water levels in 2018 were part of the project“Assessment of large-scale windthrow areas impact on hydrochemical regime and denudation of catchments located in mountain forests(Polish Tatra Mountains)”realized in 2016(MŻ,grant No.K/KDU/000334)and 2018(MŻ,grant No.K/KDU/000494),funded by the forest fund of the State Forests National Forest Holding.
文摘Strong wind events frequently result in creating large areas of windthrow, which causes abrupt environmental changes. Bare soil surfaces within pits and root plates potentially expose soil to erosion. Absence of forest may alter the dynamics of water circulation. In this study we attempt to answer the question of whether extensive windthrows influence the magnitude of geomorphic processes in 6 small second-to third-order catchments with area ranging from 0.09 km^(2) to 0.8 km^(2). Three of the catchments were significantly affected by a windthrow which occurred in December 2013 in the Polish part of the Tatra Mountains, and the other three catchments were mostly forested and served as control catchments. We mapped the pits created by the windthrow and the linear scars created by salvage logging operations in search of any signs of erosion within them. We also mapped all post-windthrow landslides created in the windthrow-affected catchments. The impact of the windthrow on the fluvial system was investigated by measuring a set of channel characteristics and determining bedload transport intensity using painted tracers in all the windthrow-affected and control catchments. Both pits and linear scars created by harvesting tend to become overgrown by vegetation in the first several years after the windthrow. The only signs of erosion were observed in 10% of the pits located on convergent slopes. During the period from the windthrow event in 2013 until 2019, 5 very small(total area <100 m^(2)) shallow landslides were created. The mean distance of bedload transport was similar(t-test, p=0.05) in most of the windthrow-affected and control catchments. The mapping of channels revealed many cases of root plates fallen into a channel and pits created near a channel. A significant amount of woody debris delivered into the channels influenced the activity of fluvial processes by creating alternating zones of erosion and accumulation.
文摘In accordance with a proposal put forward by leaders of the US Bureau of Water & Soil Conservation during a meeting with the author on July 20, 1994, this article gives a detailed account of the origin and strategies against flooding scourge in the Yangtze valley, based on the author’s research results achieved from his 15-year-long work in the Institute of Natural Tillage-free Research, Yibin City, Sichuan Province. In addition, the author puts forward suggestions aiming at eliminating the natural calamities and realizing social stability to meet the people’s long-cherished wishes, which should be considered by all government departments responsible for agriculture, forestry and the exploitation of water and other natural resources.
基金This research is part of the project“Impact of extensive windthrow areas on the dynamics of slopefluvial system”funded by the National Science Centre,Poland(Grant No.UMO-2017/27/N/ST10/00802)。
文摘Tree uprooting is an important process which leads to many geomorphic consequences.Some of the most important are the transport of sediment and mixing of soil.The aim of this article is to make a detailed examination of the magnitude of sediment transport caused by an extreme windthrow event in three severely affected catchments.Also,a comparison is made of the windthrow event with a mass movement event in the aspect of the magnitude of sediment transport and soil mixing.The study was conducted in three second-to third-order catchments in the Tatra Mountains,where a strong foehn wind event caused extensive windthrow in 2013,and a high-magnitude rainfall event triggered mass movements in 2007.The volume of sediment uplifted by the uprooting event was calculated based on the mapping of root plates using high-resolution(0.04 m)aerial images and measurements of root plate volumes conducted in the field.The volume of sediment transported by shallow landslides was determined based on a Digital Elevation Model(DEM1-m resolution).Windthrows affected 34%,76%,and94%of the area of the investigated catchments.Most of the trees had fallen downslope.The direction of treefall was influenced by the slope aspect and steepness.Root plates and pits covered 1.3%,4.8%,and 5.4%of the area of the catchments.Sediment flux generated by the uprooting event,calculated for the entire area of each investigated catchment ranged from 8.1×10^(–4) to 9.9×10^(–3) m^(3) m^(–1) event^(–1).This was notably lower than the sediment flux generated by the mass movement event(also calculated for the entire area of each catchment),which was 1.8-6.1×10^(–2)m^(3) m^(–1) event^(–1).By contrast,uprooting affected a much larger area than the mass movement event,which underlines its significant role in the mixing of soil.
文摘为量化典型黑土区主要树种根系构型特征,探究其对固土能力的影响,以该区分布较广的榆叶梅、小叶锦鸡儿、白桦、糖槭、红皮云杉、樟子松单株个体为研究对象,采用全根挖掘和WinRHIZO Pro LA2004分析系统相结合对其根系空间分布、几何形态、分形等特征进行测定,同时采用原位整株根系拉拔的方法量化根系垂直拉拔力。结果表明:榆叶梅以倾斜根为主,小叶锦鸡儿、白桦、糖槭和红皮云杉以水平根为主,樟子松根系在水平和垂直分布上较为均衡;除白桦总根表面积和红皮云杉总根长外,灌木树种总根长、总根表面积显著大于乔木,落叶阔叶乔木总根长、总根表面积显著大于针叶常绿乔木,白桦总根体积显著大于小叶锦鸡儿、糖槭、红皮云杉和樟子松;榆叶梅、小叶锦鸡儿和白桦根系分形维数和分形丰度显著大于红皮云杉和樟子松;榆叶梅、小叶锦鸡儿和糖槭整株根系平均最大垂直拉拔力显著大于白桦、樟子松和红皮云杉。主要受根系总根长、总根表面积和倾斜根数量的影响,榆叶梅、小叶锦鸡儿和糖槭根系表现出较强的固土能力,可作为典型黑土区水土保持植被构建中优先选择的树种。
