Ectomycorrhiza of <Emphasis Type="Italic">Larix sibirica</Emphasis> Ledeb. along the gradients of main ecological factors and elevation at the Northern and Subpolar Urals

Siberian larch (Larix sibirica Ledeb.) forests cover the largest areas in the Eurasian boreal zone, but there are insufficient data on its root system including the structure and functional traits of ectomycorrhizas (EM). The aim of this research is to find out if the morphological parameters of Larix sibirica EMs responded to the changes in elevation and main ecological factors (soil humidity, soil richness, soil acidity and habitat illumination). Using light microscopy, we studied EM diameter, root diameter, mantle width, and mantle volume share, share of tannin cells layers, EM density and EM length of Larix sibirica in two main types of plant communities along the elevation gradient at the Northern and Subpolar Urals. Differences in the environment were traced using phytoindication approach and the Ellenberg ecological scales. All the studied traits depend on the elevation and studied ecological factors. The diversity of fungal mantles is low, and the proportion of unstructured and pseudoparenchymatous mantles is high in response to the deterioration of the humidity, soil nitrogen content and acidity at higher-altitude habitats. Results of EM quantitative parameters measurements confirmed this pattern. We found a decline in the EM linear dimensions accompanied by a compensatory growth of the EM density with the raised elevation and the deterioration of environmental conditions.     

Study on original ecological tridimensional slope vegetation

No matter from the perspective of slope protection, landscape effect and construction cost, or from the perspective of ecological benefit, the development of original ecological tridimensional vegetation has become the inevitable trend for slope vegetation in pursuit of protecting ecological condition, decreasing soil erosion, maintaining ecological balance and beautifying environment of slope. The concept of original ecological tridimensional slope vegetation is proposed in this paper, and the original ecological tridimensional slope vegetation is studied through theoretical analysis and experiments. Specifically, the mechanical effect of slope vegetation in reinforcing the cohesion and shear strength of soil mass is firstly discussed, and then experiments are performed to study the water interception and containing function of slope under various vegetation conditions. Moreover, the relation between soil moisture and cohesion, the relation between root distribution density and cohesion, and the relation between root distribution density and soil shear strength are also studied based on experiments. Finally, based on field observation, the soil erosion states of slope under various vegetation conditions are comparatively studied. It is found that the original ecological tridimensional slope, which combines grass,shrub and tree, can generate comprehensive slope protection effects, and hence strengthen the slope protection ability and bring multiple slope protection benefits. Thereby, the theoretical foundation for developing original ecological tridimensional slope vegetation is established.     

RADIATION BALANCE AND MICROCLIMATIC FEATURES OF MARSH IN THE SANJIANG PLAIN

Radiation balance, soil temperature and the temperature and humidity of air were measured in marshes and reclaimed farmlands of the Sanjing Plain. Soil-heat flux was calculated with two different methods. Through the analysis of a lot of data, the daily variations and the law of vertical distribution of microclimate factors on marsh surface was obtained. It is found that after marshes are reclaimed, radiation balance increases, both soil temperature at different depths and air temperature of various height near ground layer rise, and air humidity decreases obviously. Therefore, one should take the establishment of artificial ecosystem of growing paddy and reed and breeding fish as the main development direction of marshes, at the same time, protect some marshes in order to prevent the environment from getting dry, and maintain regional ecological balance.     

Mechanisms of root-soil reinforcement in bioembankments of sloping farmland in the purple hilly area,China

Bio-embankment is an important soil and water conservation measure in the purple hilly area in China,which can effectively improve the ability of cultivated soil layers to resist rainfall erosion and runoff scour.In contrast,the ecological effect of bioembankment depends on the stability of the earth bank.Taking the natural grass bank as a control(CK),the root distribution,root tensile properties and shear resistance of root-soil composites for 3 typical soil and water conservation bio-embankments,namely,Morus alba Linn(Morns),Zanthoxylum bungeanum Maxim(Zanthoxylum)and Medicago sativa(Medicago)were analysed.The results included the following:(1)The root system of the bio-embankments generally decreased in extent with the soil depth;fine roots in the o-io cm depth were most prevalent and significantly higher than those at the other depths,and coarse roots were mainly distributed in the o-30cm layer.(2)The stress-strain curves of the roots of each bio-embankment were single-peak curves without clear strain softening phenomena.The smaller the root diameters were,the smoother the stress-strain curves,and the lower the capability of the earth bank to resist collapse.The larger the root diameters were,the lower the tensile strength.The average root tensile force was highest for Zanthoxylum(73.91 N),followed by Medicago(68.07N)and Morus(61.88 N),and the average root tensile strength showed the same trend,16.52 MPa for Zanthoxylum,16.08 MPa for Medicago and 13.02MPa for Morus.(3)The bio-embankment measures significantly improved the soil shear resistance,especially under vertical loads of 1oo kPa and 200kPa.The soil internal friction angle showed a significant log-positive correlation with root morphological parameters of root length density(RLD),root surface area density(RSAD) and rootweight density(RWD),while the soil cohesion force showed a positive linear correlation with these parameters.The results provide effective parameters supporting for the design of bio-embankments and promoting the use of soil reinforcement with suitable species selection in protective earth banks for stability in the purple hilly area.     

The influence of elevation on soil properties and forest litter in the Siliceous Moncayo Massif,SW Europe

Understanding the effects of elevation and related factors (climate, vegetation) on the physical and chemical soil properties can help to predict changes in response to future climate or afforestation forcings. This work aims to contribute to the knowledge of soil evolution and the classification of forest soils in relation to elevation in the montane stage, with special attention to podzolization and humus forms. The northern flank of the Moncayo Massif (Iberian Range, SW Europe) provides a unique opportunity to study a forest soils catena within a consistent quartzitic parent material over a relatively steep elevation gradient. With increasing elevation, pH, base saturation, exchangeable potassium, and fine silt-sized particles decrease significantly, while organic matter, the C/N ratio, soil aggregate stability, water repellency and coarse sand-sized particles increase significantly. The soil profiles shared a set of properties in all horizons: loamy-skeletal particle-size, extreme acidity (pH-H₂O<5.6) and low base saturation (<50%). The most prevalent soil forming processes in the catena include topsoil organic matter accumulation and even podzolization, which increases with elevation. From the upper to lower landscape positions of wooded montane stage of the Moncayo Massif, mull-moder-mor humus and an Umbrisol-Cambisol-Podzol soil unit sequences were found.     

Changes in ecosystem service of soil conservation between 2000 and 2010 and its driving factors in southwestern China

Human activities significantly alter ecosystems and their services; however, quantifying the impact of human activities on ecosystems has been a great challenge in ecosystem management. We used the Universal Soil Loss Equation and county-level socioeconomic data to assess the changes in the ecosystem service of soil conservation between 2000 and 2010, and to analyze its spatial characteristics and driving factors in the southwestern China. The results showed that cropland in the southwestern China decreased by 3.74%, while urban land, forest, and grassland areas increased by 46.78%, 0.86%, and 1.12%, respectively. The soil conservation increased by 1.88 × 10~(11) kg, with deterioration only in some local areas. The improved and the degraded areas accounted for 6.41% and 2.44% of the total land area, respectively. Implementation of the Sloping Land Conversion Program and urbanization explained 57.80% and 23.90% of the variation in the soil conservation change, respectively, and were found to be the main factors enhancing soil conservation. The 2008 Wenchuan earthquake was one of the factors that led to the degradation of soil conservation. Furthermore, industrial adjustment, by increasing shares of Industry and Service and reducing those of Agriculture, has also promoted soil conservation. Our results quantitatively showed and emphasized the contributions to soil conservation improvement made by implementing ecological restoration programs and promoting urbanization. Consequently, these results provide basic information to improve our understanding of the effects of ecological restoration programs, and help guide future sustainable urban development and regional industrial restructuring.     

九龙江流域生态环境质量遥感评价与分析

由图像TM、ASTER和“北京一号”等多时相遥感数据,建立了容纳土壤侵蚀、植被指数、土壤亮度指数、高程指数、坡度指数、降雨量指数、湿度指数和积温指数8个二级环境影响因子的指标体系和权系数,采用加权求和的方法进行运算,首次获取了1989~2003年约15年间三个时期九龙江流域生态环境质量等级及变化状况。结果表明:九龙江流域1989、1998、2003年三个时期生态环境质量总体较好。从1989年到1998年再到2003年两个阶段中,九龙江流域生态环境总体质量出现先下降再改善的特点。其变化主要表现在九龙江口周边地区,人类经济活动是影响九龙江流域生态环境质量演变的重要驱动力。     

Eco-morphological characteristics of fern species for slope conservation

Degradation of slopes due to shallow landslide and the subsequent erosional processes are a big challenge on the application of soil bioengineering techniques; that is the use of plants as main structural components of a slope protection and conservation system. An optimal application of soil bioengineering techniques should include not only the technical factor of plants as structural components but also the ecology of species and the plant adaptations to disturbances, which is crucial if a longterm successful slope restoration system is intended. Ferns are a dominant understory vegetation species in the forest of Japan, but its characteristics and influences on the recovery of shallow landslide scars have not been fully studied yet. This study aims to find out the ecological characteristics of fern species through the calculation of ecological indicators and the quantification of the morphological features of specimens growing on disturbed and non-disturbed forest slopes in Japan. Gleichenia japonica was found as the vegetation species with biggest ecological indicators on both slopes. The analysis of morphological characteristics of the specimens growing on both sites showed that the development of the specimens is focused in below-ground characteristics. The pull-out force of Gleichenia japonica root system as an indicator of ecological adaptation to a constraint environment and morphological characteristics quality is influenced by height and root length according to the principal component analysis. The eco-morphological characteristics of species can be used as an indicator of an optimal element in soil bioengineering establishment for slope conservation proposes. The long and fibrous root system could be placed on forest roads, steep or small slopes where space limitation is an issue for the establishment of bigger species and if the slope conditions allow it, it can control soil losses due to rainfall and provide stability.     

南方山地丘陵土地利用类型的地形影响GIS分析——以江西省为例

分布广泛的山地丘陵,地形复杂多样,生态环境脆弱,不合理的土地利用方式会造成生态环境的破坏,导致严重的水土流失。分析山地丘陵区土地利用的地形控制机制,对于山地丘陵区土地利用开发与水土保持等生态保护之间权衡提供科学依据而具有重要现实意义。因此,本文以南方山地丘陵分布较广泛的江西省为例,在SRTM数字高程模型(DEM)的支持下,利用中国资源环境数据中心基于Landsat遥感解译的2000年土地利用数据,分析了江西省土地利用结构与高程、坡度和坡向等地形因子的关系。结果表明地形因子是影响江西省土地利用方式的一个重要因素,具体表现在:(1)随着高程和坡度的增加,耕地面积及占土地总面积的比例都呈下降趋势,南坡耕地面积和比例都大于北坡的耕地面积和比例;(2)在低海拔区,林地面积占土地总面积比例随着海拔高程的增加而增加,当海拔高于400米时,基本稳定;(3)居民点和工矿用地受高程和坡度的影响较大,受坡向影响较小;(4)草地的面积随着海拔的增加呈下降趋势,但其面积比随着高程增加呈缓慢增加,受坡度和坡向的影响较小。     

Soil physicochemical properties and vegetation structure along an elevation gradient and implications for the response of alpine plant development to climate change on the northern slopes of the Qilian Mountains

Elevation is one of key factors to affect changes in the environment, particularly changes in conditions of light, water and heat. Studying the soil physicochemical properties and vegetation structure along an elevation gradient is important for understanding the responses of alpine plants andtheir growing environment to climate change. In this study, we studied plant coverage, plant height, species richness, soil water-holding capacity, soil organic carbon(SOC) and total nitrogen(N) on the northern slopes of the Qilian Mountains at elevations from2124 to 3665 m. The following conclusions were drawn:(1) With the increase of elevation, plant coverage and species richness first increased and then decreased, with the maximum values being at 3177 m.Plant height was significantly and negatively correlated with elevation(r=–0.97, P0.01), and the ratio of decrease with elevation was 0.82 cm·100 m-1.(2) Both soil water-holding capacity and soil porosity increased on the northern slopes of the Qilian Mountains with the increase of elevation. The soil saturated water content at the 0-40 cm depth first increased and then stabilized with a further increase of elevation, and the average ratio of increase was2.44 mm·100 m-1. With the increase of elevation, the average bulk density at the 0-40 cm depth first decreased and then stabilized at 0.89 g/cm3.(3) With the increase of elevation, the average SOC content at the 0-40 cm depths first increased and then decreased,and the average total N content at the 0-40 cm depth first increased and then stabilized. The correlation between average SOC content and average total N content reached significant level. According to the results of this study, the distribution of plants showed a mono-peak curve with increasing elevation on the northern slopes of the Qilian Mountains. The limiting factor for plant growth at the high elevation areas was not soil physicochemical properties, and therefore,global warming will likely facilitate the development of plant at high elevation areas in the Qilian Mountains.     

Ecological impact assessment method of highways in Tibetan Plateau:A Case study of Gonghe-Yushu Expressway

In recent years,the ecological environment along highways in Tibetan Plateau has been severely affected due to the rapid construction of highways.In order to solve the problems of multiple indicators and inconsistent criteria in the ecological impact assessment of highways,and to scientifically screen assessment indicators,the paper proposes a multi-round indicator screening method,which combines literature analysis,expert rating,and statistical analysis.Based on this screening method,normalized difference vegetation index,land surface temperature,elevation,and normalized difference soil index are screened out.Combined with multiple linear regression,an ecological impact assessment model is established and applied to ecological impact assessment of Gonghe-Yushu Expressway.The results show that the expressway construction is the first driving force for the deterioration of the ecological environment along the roadside,and its interference range on the desert grassland ecosystem is greater than that on the agroforestry system.The ecological environment within 150 m on both sides of the expressway should be protected.     

Characteristics of rock fragments in different forest stony soil and its relationship with macropore characteristics in mountain area,northern China

Rock fragments have major effect on soil macropores and water movement. However, the characteristics of rock fragments and their relationship with macropore characteristics remain elusive in forest stony soils in northern mountainous area of China. The objectives of this study are to (1) use Industrial Computed Tomography (CT) scanning to quantitatively analyze rock fragment characteristics in intact soil columns in different forest lands and (2) identify the relationship between characteristics of rock fragments and that of the macropores. Intact soil columns that were 100 mm in diameter and 300 mm long were randomly taken from six local forest stony soils in Wuzuolou Forest Station in Miyun, Beijing. Industrial CT was used to scan all soil column samples, and then the scanned images were utilized to obtain the three-dimensional (3D) images of rock fragments and macropore structures. Next, the parameters of the rock fragments and macropore structure were measured, including the volume, diameter, surface area, and number of rock fragments, as well as the volume, diameter, surface area, length, angle, tortuosity and number of macropores. The results showed that no significant difference was found in soil rock fragments content in the 10-30 cm layer between mixed forest and pure forest, but in the 0-10 cm soil layer, the rock fragments in mixed forest were significantly less than in pure forest. The number density of macropores has significant negative correlation with the number of rock fragments in the 0-10 cm soil layer, whereas this correlation is not significant in 10-20 cm and 20-30 cm soil layers. The volume density of macropore was not correlated with the volume density of rock fragments, and there is no correlation between the density of macropore surface area and the density of rock fragment surface area. Industrial CT scanning combined with image processing technology can provide a better way to explore 3D distribution of rock fragments in soil. The content of rock fragments in soil is mainly determined by parent rocks. The surface soil (0-10 cm) of forest contains fewer rock fragments and more macropores, which may be caused by bioturbation, root systems, gravitational settling and faunal undermining.     

Shrub Communities and Environmental Variables Responsible for Species Distribution Patterns in an Alpine Zone of the Qilian Mountains,Northwest China

Understanding the factors that drive variation in species distribution is a central theme of ecological research. Although several studies focused on alpine vegetation, few efforts have been made to identify the environmental factors that are responsible for the variations in species composition and richness of alpine shrublands using numericalmethods. In the present study, we investigated vegetation and associated environmental variables from 45 sample plots in the middle Qilian Mountains of the northwestern China to classify different community types and to elucidate the speciesenvironment relationships. We also estimated the relative contributions of topography and site conditions to spatial distribution patterns of the shrub communities using the variation partitioning. The results showed that four shrub community types were identified and striking differences in floristic composition were found among them. Species composition greatly depended on elevation, slope,shrub cover, soil p H and organic carbon. The important determinants of species richness were soil bulk density and slope. No significant differences in species richness were detected among the community types. Topography and site conditions had almost equal effects on compositional variation. Nonetheless,a large amount of the variation in species composition remained unexplained.     

Anatomical variation of five plant species along an elevation gradient in Mexico City basin within the Trans-Mexican Volcanic Belt,Mexico

Change in environmental conditions with altitudinal gradients induces morpho-anatomical variations in plants that have been poorly documented in intertropical regions. Five species with three life forms, cryptophyte (Alchemilla procumbens, Geranium seemannii), hemicryptophyte (Acaena elongata, Lupinus montanus), and phanerophyte (Symphoricarpos microphyllus), distributed along an altitudinal gradient in the Sierra Nevada of central Mexico, were studied. The aims were to identify and evaluate their morpho-anatomical modifications under the hypothesis that the sizes of individuals and of their wood and leaf cell types decrease as elevation increases. Three individuals per species per site were collected at seven locations along the altitudinal gradient (2949-3952 m). Their morpho-anatomical characters were analyzed through multiple regression analyses. Elevation was the variable that best explained anatomical changes in the leaf and wood of the five species. Canopy density and potassium content in the soil also contributed to explain the variation in anatomical variables along the gradient. As elevation increased a bimodal pattern was observed in various anatomical characters as in the leaf width of A. elongata, A. procumbens and G. seemannii and in the vessel diameter of A. procumbens, G. seemannii, and L. montanus. Other features as the vessel diameter of A. elongata, the fiber length of S. microphyllus, and the ray width of A. elongata increased as the elevation increased. Anatomical traits have a tendency to decrease in size but just toward the end of the gradient, which is probably related to changes in canopy density. The plant response to the altitudinal gradient is more focused on anatomical adaptations than morphological variation; it is also species dependent.     

淮河流域上消化道肿瘤与环境污染的模型分析

 自20世纪70年代后期以来,淮河流域不断遭受工业点源污染和其他面源污染,媒体也陆续报道了淮河流域"癌症村"的出现。本文探讨了淮河流域14个监测县5810个行政村的消化道肿瘤与环境因子之间的空间分布规律。作者从流域和行政区划等多维空间角度出发,通过全局的最小二乘法线性回归和稳健回归对环境因子进行筛选分析,以局部地理加权回归方法探测各类环境因子,在不同地区对贝叶斯调整的上消化道肿瘤死亡率的影响程度,建立了消化道肿瘤死亡的风险评估模型,其中,包括地表水水质等级、浅层地下水质量分级、河网密度、土壤多环芳烃含量分级、化肥施用量和经济密度等6类环境危险因素。根据局部回归模型中各监测点环境因子的回归系数和统计学检验结果,提取出当地主要的环境影响因素。从14个监测县区总体上看,地表水水质等级和GDP与肿瘤呈负相关,其他环境因子均与肿瘤死亡存在正相关。但从局部角度看,不同地区环境影响因子种类和影响强度有较大差别。其中淮河流域江苏段以化肥施用量、土壤多环芳烃含量、GDP和河网密度为主要影响因子,安徽段以土壤多环芳烃含量和化肥为主,河南段主要是以地下水质量分级、河网密度和化肥为主,同时河南沈丘县地表水水质等级对当地影响较大。山东段虽然也探测出来部分环境危险因子的存在,但没有发现其与肿瘤死亡的关联关系,尚需进一步深化研究。     

基于长时间序列遥感数据的阿伯德尔国家公园 生态环境质量评价

阿伯德尔国家公园位于号称肯尼亚“水塔”的阿伯德尔山脉上,是肯尼亚重要的旅游景区和珍稀动植物保护区,开展该地生态环境质量评价对肯尼亚水资源保护与可持续发展具有重要的意义。本研究基于1987-2018年的Landsat系列遥感数据,通过计算综合遥感生态指数RSEI,结合趋势线分析法对阿伯德尔国家公园近32年间生态环境质量变化进行客观定量分析。研究结果显示：① 1987-2018年研究区RSEI均值从0.62下降到0.51,生态环境质量退化的区域面积为551.52 km ²,占总面积的71.85%,表明在气候变化和人类活动影响下,1987-2018年研究区的环境状况呈恶化趋势;②环境质量显著恶化的区域主要分布于亚高山植被区和东部低海拔森林覆盖区,亚高山地区植被生态系统结构单一,稳定性差,对气候变化和人类活动更为敏感;而东部区域存在过度开发,非法砍伐森林等现象,且旅游开发强度大,环境恶化与人类活动密切相关。     

西北地区土壤资源特征及其开发利用与保护

在分析西北地区土壤分布规律的基础上,研究了不同类型区土壤的资源特征及其在开发利用中存在的问题,认为黄土地区土壤土质疏松、粉砂含量高、富含碳酸钙是水土流失的物质基础;干旱区广为分布的荒漠土壤资源的性能低劣、绿洲区水土资源的利用比例失调是造成土地荒漠化、土壤盐渍化的根本原因;而高原土壤的粗骨性、土层浅薄、有效肥力低则加速了草场的退化和沙漠化.提出了西北地区土壤资源的合理利用与生态环境保护相协调的途经,即搞好农田基本建设,采用旱作技术节水和合理用水,扩大林草植被,保护天然草场和林木.并认为西北土壤资源的开发利用要在充分发挥其生产潜力的同时,首先应遵循生态规律,开发与保护并重,防止土壤资源衰竭和破坏.     

基于GridMet模型的浙江省温湿指数空间分布及地形影响分析

温湿指数是气候舒适度评价模型之一,通过温度与湿度的组合反映人体与周围环境的热量交换,本文利用2003-2018年浙江省及其周边71个气象站点月平均气温、地面水汽压数据,以及MODIS水汽产品,基于GridMet模型模拟了浙江省各月温湿指数空间分布（100 m×100 m）,分析了浙江省温湿指数随地形因子（海拔、坡度、坡向）变化的特征;讨论了各地形因子对温湿指数空间分布的影响程度。结果表明：① 海拔、坡度、坡向3个地形因子中,1月温湿指数随坡向的变化最大,7月最小;② 同坡向上,坡度变化对1月温湿指数影响较大,而海拔变化则是对7月影响最大;③ 南坡1月温湿指数随海拔和坡度增加均略为增加,南坡其他月份及北坡各月均为随海拔和坡度增加温湿指数减小;④ 北坡相对于南坡而言,海拔和坡度对温湿指数的影响更为明显。浙江大部分山区由于地形影响,夏季较为“舒适”,适宜建立避暑消夏的旅游项目。     

Spatial variability and its main controlling factors of the permafrost soil-moisture on the northern-slope of Bayan Har Mountains in Qinghai-Tibet Plateau

The soil moisture movement is an important carrier of material cycle and energy flow among the various geo-spheres in the cold regions. Thus, this research takes the north slope of Bayan Har Mountains in Qinghai-Tibet Plateau as a case study. The present study firstly investigates the change of permafrost moisture in different slope positions and depths. Based on this investigation, this article attempts to investigate the spatial variability of permafrost moisture and identifies the key influence factors in different terrain conditions. The method of classification and regression tree (CART) is adopted to identify the main controlling factors influencing the soil moisture movement. The relationships between soil moisture and environmental factors are revealed by the use of the method of canonical correspondence analysis (CCA). The results show that: 1) Due to the terrain slope and the freezing-thawing process, the horizontal flow weakens in the freezing period. The vertical migration of the soil moisture movement strengthens. It will lead to that the soil-moisture content in the up-slope is higher than that in the down-slope. The conclusion is contrary during the melting period. 2) Elevation, soil texture, soil temperature and vegetation coverage are the main environmental factors which affect the slope-permafrost soil-moisture. 3) Slope, elevation and vegetation coverage are the main factors that affect the slope-permafrost soil-moisture at the shallow depth of 0-20 cm. It is complex at the middle and lower depth.     

Siberian silkmoth outbreaks surpassed geoclimatic barrier in Siberian Mountains

Siberian silkmoth(SSM,Dendrolimus sibiricus Tschetv.) is the most important defoliator of Siberian pine(Pinus sibirica Du Tour) and fir(Abies sibirica Ledeb.) stands.Warming-induced SSM outbreaks are one of the major driving factors of successions within the taiga zone.It is suggested that climate change impacted the SSM range and life cycle.We analyzed the migration of alpine and northerly SSM outbreak boundaries in Siberia and the impact of the climate variables and topography on the outbreak dynamics.We used time-series scenes(multispectral data,and vegetation indexes EVI and NDII) in combination with field studies,climate variables,and GIS techniques.We found that SSM outbreaks in the area of alpine boundary shifted about 370 m uphill since the mid of 1950.The outbreak onset was promoted by increased dryness and active temperatures and decreased root zone moisture content in the spring-early summer period.The terrain topography strongly affected SSM outbreak onset and dynamics.Initially,the outbreak was located at the middle elevations on the gentle concave southeastern slopes,which are the favorable insect habitats between outbreaks.Then the outbreak expanded uphill and downhill,to steeper slopes,and both concave and convex terrains.Alongside with elevation range expansion,SSM surpassed its northern historical outbreak boundary:the potential outbreaks' boundary moved about 300 km northward.Climate warming contributes to SSM migration into former outbreak free conifer stands located in highlands and at northern latitudes.