Effects of Environmental Factors on Tree Seedling Regeneration in a Pine-oak Mixed Forest in the Qinling Mountains, China

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 southwest （20°-75°） whereas gradually from the 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-1 to 1,525 trees ha-1） whereas the sapling density was significantly lower in stands （1,9oo trees ha-O. 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.

Residents'environmental conservation behaviour in the mountain tourism destinations in China:Case studies of Jiuzhaigou and Mount Qingcheng

This study aimed at gaining an understanding of the formation of residents' Environmental Conservation Behaviour(ECB) to promote sustainable tourism development in Chinese mountain areas. In particular, a theoretical framework was constructed by merging residents' mountain attachment and their environmental values,and awareness of environmental consequences based on the Cognition Behaviour Theory. This research sampled 642 residents with convenience sampling method in Jiuzhaigou and Mount Qingcheng, and structural equation modelling analysis was conducted to identify the relationships among the above variables. Results verified that mountain attachment affected people's awareness of environmental consequences, which then affected their ECB.Environmental values and mountain attachment directly and positively influenced ECB. Moreover,awareness of environmental consequences played the most prominent role in predicting ECB among all the predictors in this study. In all, this study derived several significant implications which can not only contribute to environmental management policies in tourism field but also help to improve the levels of the antecedents of residents' ECB and promote sustainable tourism development in Chinese mountain areas.

Altitude as environmental filtering influencing phylogenetic diversity and species richness of plants in tropical mountains

Elucidating how multiple factors affect biodiversity and plant community assembly is a central issue in ecology,especially in vulnerable ecosystems such as tropical mountains.These studies are more relevant in global warming scenarios that induce the upward displacement of plant species towards reduced habitats and hostile environments in tropical mountains.This study aimed to analyze how altitude affects taxonomic and phylogenetic diversity in plant communities of tropical mountains.Thus,we tested if(i)increased altitude works as an environmental filtering promoting decreased species richness,decreased phylogenetic diversity,and increased phylogenetic clustering in these tropical mountains;and if(ii)plant communities of high altitude in tropical mountains are also result of recent diversification with plant species recently split shortening phylogenetic distances between closest related species.We tested effects of altitude on species richness and phylogenetic metrics using linear mixed-effects models.Mount Haleakala presented 114 species,Mount Kilimanjaro presented 231 species and Mount Purace presented 280 species.We found an environmental filtering effect with increasing altitude causing phylogenetic clustering,decreased phylogenetic diversity and decreased species richness.The decreasing phylogenetic distances between closest relatives are congruent with neo-endemics,suggesting recent plant diversification in high altitudes of tropical mountains,possibly driven by geographic isolation and environmental heterogeneity.Consequences of global warming should be monitored in tropical mountains focusing on distribution shifts.

Impact of typical environments in China’s western mountainous areas on the durability of railway concrete:a review

Purpose–This study aims to analyze the impact mechanism of typical environments in China’s western mountainous areas on the durability of railway concrete and propose measures to improve durability.Design/methodology/approach–With the continuous promotion of infrastructure construction,the focus of China’s railway construction has gradually shifted to the western region.The four typical environments of large temperature differences,strong winds and dryness,high cold and low air pressure unique to the western mountainous areas of China have adverse effects on the durability of typical railway structure concrete(bridges,ballastless tracks and tunnels).This study identified the characteristics of four typical environments in the western mountainous areas of China through on-site research.The impact mechanism of the four typical environments on the durability of concrete in different structural parts of railways has been explored through theoretical analysis and experimental research;Finally,a strategy for improving the durability of railway concrete suitable for the western mountainous areas of China was proposed.Findings–The daily temperature difference in the western mountainous areas of China is more than twice that of the plain region,which will lead to significant temperature deformation and stress in the multi-layered structure of railway ballastless tracks.It will result in cracking.The wind speed in the western plateau region is about 2.5 to 3 times that of the plain region,and the average annual rainfall is only 1/5 of that in the plain region.The drying effect on the surface of casting concrete will significantly accelerate its cracking process,leading to serious durability problems.The environmental temperature in the western mountainous areas of China is generally low,and there are more freeze-thaw cycles,which will increase the risk of freeze-thaw damage to railway concrete.The environmental air pressure in the western plateau region is only 60%of that in the plain region.The moisture inside the concrete is more likely to diffuse into the surrounding environment under the pressure difference,resulting in greater water loss and shrinkage deformation of the concrete in the plateau region.The above four issues will collectively lead to the rapid deterioration of concrete durability in the western plateau region.The corresponding durability improvement suggestions from theoretical research,new technology development and standard system was proposed in this paper.Originality/value–The research can provide the mechanism of durability degradation of railway concrete in the western mountainous areas of China and corresponding improvement strategies.

CFD Investigation of Diffusion Law and Harmful Boundary of Buried Natural Gas Pipeline in the Mountainous Environment

The leakage gas from a buried natural gas pipelines has the great potential to cause economic losses and environmental pollution owing to the complexity of the mountainous environment.In this study,computational fluid dynamics(CFD)method was applied to investigate the diffusion law and hazard range of buried natural gas pipeline leakage in mountainous environment.Based on cloud chart,concentration at the monitoring site and hazard range of lower explosion limit(LEL)and upper explosion limit(UEL),the influences of leakage hole direction and shape,soil property,burial depth,obstacle type on the diffusion law and hazard range are analyzed.Results show that the leakage gas is not radially diffused until it reaches the ground,and the velocity of gas diffusion to the ground and the hazard range decrease as the angle between the leaking direction and the buoyancy direction increases.Triangular and square leak holes have a faster diffusion rate and a wider hazard range than circular.The diffusion rate of leakage gas in soil rises as soil granularity and porosity increase.The time of leakage gas diffusion to the ground increases significantly with the increase of burial depth,and the hazard range reduces as burial depth increases.Boulder-type obstacles will alter the diffusion path of the leakage gas and accelerate the expansion of the hazard distance,while trench-type obstacles will cause the natural gas to accumulate in the trench and form a high concentration region slowing the expansion of the surface gas concentration.

Early Holocene High Magnitude Debris Flow Events and Environmental Change as Illustrated by the Moxi Platform, Hengduan Mountains, SW China

Thick debris flow deposits in the Hengduan Mountains of southwestern China record landscape instability at the close of the last glaciation and in the early Holocene. The deposits, ranging in thickness from 100 to 200 m, are common and in high magnitude in the valleys of this region. They are products of large debris flows induced by glacier and enabled by the presence of large amount of glacial debris on the landscape. The carbon 14 dating from Moxi Platform indicates that a period of catastrophic debris flows occurred at c. 7 kyr B.P., and was concurrent with other glacial-fluvial fans and terraces which tied to regional climatic oscillations elsewhere in the Himalaya. The comparable events suggest a strong climatic control on earth surface processes for the dynamics, magnitude, and frequency in this region.

Environmental significance and hydrochemical characteristics of rivers in the western region of the Altay Mountains,China

Analysis of environmental significance and hydrochemical characteristics of river water in mountainous regions is vital for ensuring water security.In this study,we collected a total of 164 water samples in the western region of the Altay Mountains,China,in 2021.We used principal component analysis and enrichment factor analysis to examine the chemical properties and spatiotemporal variations of major ions(including F-,Cl-,NO_(3)-,SO_(4)^(2-),Li+,Na+,NH4+,K+,Mg^(2+),and Ca^(2+))present in river water,as well as to identify the factors influencing these variations.Additionally,we assessed the suitability of river water for drinking and irrigation purposes based on the total dissolved solids,soluble sodium percentage,sodium adsorption ratio,and total hardness.Results revealed that river water had an alkaline aquatic environment with a mean pH value of 8.00.The mean ion concentration was ranked as follows:Ca^(2+)>SO_(4)^(2-)>Na+>NO_(3)->Mg^(2+)>K+>Cl->F->NH_(4)+>Li+.Ca^(2+),SO_(4)^(2-),Na+,and NO_(3)-occupied 83%of the total ion concentration.In addition,compared with other seasons,the spatial variation of the ion concentration in spring was obvious.An analysis of the sources of major ions revealed that these ions originated mainly from carbonate dissolution and silicate weathering.The recharge impact of precipitation and snowmelt merely influenced the concentration of Cl-,NO_(3)-,SO_(4)^(2-),Ca^(2+),and Na+.Overall,river water was in pristine condition in terms of quality and was suitable for both irrigation and drinking.This study provides a scientific basis for sustainable management of water quality in rivers of the Altay Mountains.

THE ENVIRONMENTAL QUALITY AND RENOVATING PLAN OF THE LOESS PLATEAU AND LIUPANSHAN MOUNTAINOUS AREA IN NINGXIA

1. The environmental quality of the Loess Plateau and Liupanshan mountainous area in Ningxia The landuse structure in the studied region was very irrational in 1970s, the propor-tions covered by farming, forestry and animal husbandry are separately 50.91%, 6.32% and33.3%. Since 1980s, the farmland has been returned back to forestry and pasture so that

Mountain evolution and environmental changes of Huangshan(Yellowmountain),China

Huangshan (Yellow Mountain) is located in southern part of the lower reaches of the Yangtze River. The highest Lotus Flower peak is 1864 m above sea level. Formative ages of the Huangshan and its granite,process of mountain geomorphic evolution from the Eocene to Quaternary,environmental changes of Quaternary, formative origin of beautiful peaks and fascinating rocks were studied and the questionable 'Pleistocene glaciation' was also discussed in this paper.

Organic-walled Microfossils from the Early Middle Cambrian sediments of the Holy Cross Mountains,Poland：Possible Implications for Sedimentary Environment in the SE Margin of the Baltica

An association of organic-walled microfossils consisting of filamentous cyanobacteria, algal coenobia and acanthomorphic acritarch have been documented from non-calcareous claystones and mudstones of the Pepper Mountains Shale Formation（PMSF）, located in its stratotype area in the Pepper Mountains, which are part of the Holy Cross Mountains in Poland. These sediments represent the oldest strata of the ？ysogóry Unit, deposited on the edge of the East European Craton（Baltica）. Non-branched, ribbon-like and thread-like cyanobacteria trichomes exhibit morphological similarities to families Nostocaceae and Oscillatoriaceae. Cells assembled in rounded to irregular clusters of monospecific agglomerations represent multicellular algal coenobia, attributed to the family Scenedesmaceae. The co-occurrence of acritarchs belonging to species as Eliasum llaniscum, Cristallinium ovillense and Estiastra minima indicates that the studied material corresponds to the lower Middle Cambrian. Deposition of the PMSF took place in shallow marine environment, influenced by periodical freshwater inputs. The varying degree of coloration of organic-walled microfossils is interpreted in this study as factor indication of possible different source of their derivation. Dark brown walls of cells assembled in algal coenobia might have sustained previous humification in humid, terrestrial environments, which preceded their river transport into the sea together with nutrients, causing occasional blooms of cyanobacteria in the coastal environment and the final deposition of both groups of organisms in marine deposits.

Assessing discharge periodicity in mountain catchments using classified environmental conditions(Tatra Mountains, Poland)

The periodicity of a river expressed in cycles of various lengths(monthly, seasonal,multiannual) is a result of climatic factors and overlapping environmental conditions within its catchment. In uncontrolled or poorly surveyed catchments, it is very difficult to determine the duration of a stream’s hydrological activity. This is especially relevant for catchments with complicated water circulation in karstic rocks. The present study concerns the small catchment of the Str??yski Potok river located in the area of the Tatra National Park, in the Western Tatras. The observation period covered the 2015 hydrological year, which differed hydrologically from average conditions. This study aims to develop a simple method to explain the processes shaping the mountain stream discharge periodicity. The research employed periodic field observations linked with climatic and non-climatic factors. Environmental conditions were assessed as four classes reflecting their influence on appearance or disappearance of mountain stream water. Class boundaries were the values of quartiles. The degree of correspondence between environmental factors and stream field observations was described via the Index DC(Degree Correspondence Index) approach.Complete correspondence(Index DC =0) was found in 23% catchments, a weak relationship between conditions favouring discharge and actual condition(Index DC=-1, +1) was noted within 11 catchments,while in 9 catchments, no such relationship was found(Index DC =-2, +2). The obtained results indicate a correspondence or lack thereof between the environmental potential of the catchment and its discharge periodicity. The discrepancies between the assessment of the influence of climatic and nonclimatic factors and the data collected during field observations provide a basis for more detailed studies.Continuation of these studies based on the proposed classifications will allow for a more complete explanation of water disappearance in river channels and the determination of their short-and long-term discharge periodicity.

Environmental Data Acquisition, Elaboration and Integration： Preliminary Application to a Vulnerable Mountain Landscape and Village （Novalesa, NW Italy）

Climate conditions play a crucial role in the survival of mountain communities, whose survival already critically depends on socioeconomic factors. In the case of montane areas that are prone to natural haz-ards, such as alpine slope failure and debris flows, climatic factors exert a major influence that should be considered when creating appropriate sustainable scenarios. In fact, it has been shown that climate change alters the availability of ecosystem services （ES）, thus increasing the risks of declining soil fertility and reduced water availability, as well as the loss of grassland, potential shifts in regulatory services （e.g., protection from natural hazards）, and cultural services. This study offers a preliminary discussion on a case study of a region in the Italian Alps that is experiencing increased extreme precipitation and erosion, and where an isolated and historically resilient community directly depends on a natural resource econ- omy. Preliminary results show that economic factors have influenced past population trends of the Novalesa community in the Piemonte Region in northwest Italy. However, the increasing number of rock fall and debris flow events, which are triggered by meteo-climatic factors, may further influence the livelihood and weflbeing of this community, and of other similar communities around the world, Therefore, environmental monitoring and data analysis will be important means of detecting trends in landscape and climate change and choosing appropriate planning options. Such analysis, in turn, would ensure the survival of about 10% of the global population, and would also represent a possibility for future economic development in critical areas prone to poverty conditions.

Source and environmental significance of oxalate in Laohugou Glacier No. 12, Qilian Mountains, Western China

Retrieval of oxalate from snow and ice provides information on past environmental changes. In recent years, records of organic acids in middle-and low-latitude glaciers have attracted the attention of researchers globally. In this study, we analyzed oxalates in an ice core from Laohugou Glacier No. 12 on the Qilian Mountains at an elevation of 5,040 m a.s.l. in2006. Average oxalate concentration was 18.5±2.4 ng/g over the prior 46 years. Oxalate values showed a significantly increasing trend since 1985. From 1985 to 1995, oxalate concentrations had large fluctuations, peaking in about 1987 and exhibiting a slightly decreasing trend since 1995. The result shows that the abrupt increase of oxalate concentration in the ice core since the mid-1980 s reflects atmospheric environmental pollution by human and industrial activities.

Morphological Characteristics and Environmental Implications of Phytoliths in Topsoils from Different Vegetation Zones on Northern Slope of Changbai Mountains,China

The Changbai Mountains,located in the temperate monsoon climate zone of East Asia,is an ideal loca-tion for the research on timberline response to global changes.In this study,the topsoils were collected from different vertical vegetation zones on the northern slope of the Changbai Mountains,Northeast China in August 2009,and phytoliths in the soil samples were extracted by using wet oxidation method and identified with Motic 2.0 microscope in laboratory.The results show that phytoliths are abundant in the topsoils of the study area.The herbal phytoliths are primarily composed of elongated,tooth-shaped,point-shaped and hat-shaped phytoliths,as well as a small amount of fan-shaped and square-shaped ones.The elongated,tooth-shaped,point-shaped and hat-shaped phytoliths are representative of cold climate,while fan-shaped and square-shaped ones are representative of warm and humid climate.In the conifer broadleaved mixed forest zone,coniferous forest zone and broadleaf forest zone,there are close correlations between vegetation and woody phytoliths in the topsoils,indicating that the woody plants of a region can be reconstructed from the woody phytolith assemblages in the topsoils.Meanwhile,the topsoil phytolith assemblages can also be used to reconstruct the understory herbs effectively.The phytolith assemblages in the topsoils of the forest community and herbal community differ significantly,which can help indicate the historical location of the timberline.

Outdoor thermal environmental research of the mountainous city by GIS

The study of urban outdoor thermal environment was carried out in one of the mountainous cities by using geography information system(GIS) technique which is connected with predicting and evaluating models for the outdoor thermal environment, monitoring data and simulating data. A prediction and evaluation system were set up. A typical mountainous city, i.e., Yunyang city in Chongqing in China, was taken as an example, its urbanization trend and population growth was predicted and evaluated. The heat island intensity and its trend were simulated, the temperature field, velocity field and the humidity field were analyzed. The results show that GIS is an effective tool to deal with the outdoor thermal environment, especially for the mountainous cities with special geographical particularities. GIS can be used in the environmental management and the city planning especially for the mountainous cities.

Legislation Characteristics and Implementation Recommendations for Ecological and Environmental Protection Regulations on Qinling Mountains in Shaanxi Province

This paper analyzed status and significance of Ecological and Environmental Protection Regulations on Qinling Mountains in Shaanxi Province in structure of Shaanxi local environmental laws.Theses Regulations have two outstanding characteristics:firstly,integrated protection and development,accurately regulating and guiding relation coordination;secondly,attaching great importance to using economic means to protect ecological environment and provide basis for administration according to law.It came up with specific methods for speeding up formulation of Regulations,making effort to explore implementation cases for development of Guanzhong economic zone and Qinling Mountains ecological protection,establishing methods and systems for ecological and environmental protection follow-up monitoring and evaluation of Qinling Mountains,and raising these Regulations to national laws of Ecological and Environmental Protection for Qinling Mountains.

Influence of environmental predispositions on temperate mountain forest damage at different spatial scales during alternating drought and flood periods:case study in Hruby Jeseník Mts.(Czech Republic)

Mountain forests are more prone to environmental predispositions(EPs)than submountain ones.While remote sensing of mountain forests enables instantaneous damage mapping,the investigation of the causes requires field data.However,a local field or regionally modeled environmental characteristics influence remote data evaluation differently.This study focused on the evaluation of EPs effects damaging mountain forests between various spatial resolutions during environmental change.The evaluation was divided into managed and natural forests in the Hruby Jeseník Mts.(Czech Republic;240-1491 m a.s.l.;50.082°N,17.231°E).Damage was assessed through the discrimination analysis of the normalised difference vegetation index(NDVI)by MODIS VI during alternating drought and flood periods 2003-2014.The local environmental influence was assessed using the discrimination function(DF)separability of forest damage in the training sets.The regional influence was assessed through map algebra estimated via the DF and a forest decline spatial model based on EPs from differences between risk growth conditions and biomass fuzzy sets.Management,EPs and soil influenced forest NDVI at different levels.The management afflicted the NDVI more than the EPs.The EPs afflicted the NDVI more than the soil groups.Strong winters and droughts had a greater influence on the NDVI than the flood events,with the winter of 2005/2006 inverting the DF direction,and the 2003 drought increasing differences in managed forest biomass and decreasing differences in natural forest biomasses.More than 50% of declining managed forests in the training sets occurred on Leptosols,Podzols and Histosols.On a regional scale,the soil influence was eliminated by multiple predispositions.The EPs influenced 96% of natural forest and 65% of managed forest,though managed forest damage was more evident.The mountain forest NDVI decline was dependent on both management and risk predispositions.

Wildlife Crossing Zones along the Ring Changbai Mountain Scenic Highway, China

The 84-km long Changbai Mountain scenic Ring highway encircles and bisects the nature reserve. With the expected increasing traffic flow, increased wildlife vehicle collisions and barrier effects are likely. In order to identify wildlife crossing zones and future protective measurement, the authors carried out 10 wildlife highway crossing surveys during the winter in 2008-2009. For each 5-kin section, the authors recorded highway crossings of all small/mid-sized and large mammals and one large protected bird species, the hazel grouse （Bonasa bonasia） and noted snow depth and the dominant vegetation type. The authors detected 12 mammal species and one avifauna species crossing the highway 502 times. The smallest of mammal was the Eurasian red squirrel （Sciurus vulgaris）. Large mammals detected included the wild boar （Sus scrofe） （64） and brown bear （Ursus arctos） （1）. The average number of wildlife crossings per 5 km was 29.5. It was found that species richness and crossing frequency was higher in sections with broad leaf forest compared to sections with white birch secondary forest significantly. The authors suggested that disturbance of broad leaf forest be minimized during construction and strict protection be established for broad leaf forests around Changbai Mountain National Nature Reserve.

Environmental evolution of Gongwang Mountains during Holocene in northeastern Yunnan,China

This paper presents the study on two continuous glacio-lacustrine sedimentary deposits, Laotanfang （3 597 m） and Shibantang （3 689 m） located on the southern and northern sides of Hulifang peak in Yunan, China. Environmental change indexes are constructed for each deposit, based on grain size, geochemical and pollen analysis, environmental magnetic susceptibility, and 14C dating. The study of climatic environmental change since the Holocene epoch in this region shows that the climate fluctuated at different stages during the early Holocene, that is, the climate was cool and wet during 8.4-7. 7r ka, cold and wet during 7.7-6. 5 ka, cold and dry during 6. 5-4.7 ka, cool and wet during 4.7-2. 1 ka, warm and wet during 2. 1-1.0 ka, and warmer and wet since 1 ka. These findings reflect the overlapping influences of the southwest and southeast monsoons in different times during the Holocene in the north part of southwestern China are in accord with other Holocene climate change models in this part of China.

Study on Environmental-Geological Problem and Ecosystem Re-establishment Countermeasures About Quarry and Damaged Mountain in Peri-urban

The quarry and damaged mountain in peri-urban have an important influence to ecological environment. They have had a series of serious environmental -geological problems to the socio-economic development and urban modernization process, such as increased environmental pollution and soil erosion,destruction of landscape aesthetic。