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Vegetation structural characteristics and topographic factors in the remnant moist Afromontane forest of Wondo Genet, south central Ethiopia

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Journal of Forestry Research 2013年第3期24卷 419-430页

作者： Mamo Kebede Markku Kanninen Eshetu Yirdaw Mulugeta Lemenih Viikki Tropical Resources Institute (VITRI) Department of Forest Sciences University of Helsinki Hawassa University Wondo Genet College of Forestry and Natural Resources

For forest ecosystem management to be effective, knowledge of the horizontal and vertical structural diversity of a forest is essential. The moist Afromontane highlands of Wondo Genet in south-central Ethiopia present an opportunity to restore and rehabilitate and enhance the ecosystem services to be obtained from this forest sustainably. We focused on the forest structural characteristics to better understand the current forest conditions to assist in the sustainable management of this resource. A total of 75 （20 m × 20 m） quadrats were sampled and diame- ter at breast height （DBH）〉2 cm and stem height 〉2 m were measured. Species identity and abundance, elevation, slope, and aspect were recorded for each plot. Structural characteristics were computed for each plot. Relationship of topographic factors with vegetation characteristics was conducted using R-Software. A total of 72 woody species was re- corded. Whereas, the overall diameter distribution shows an inverted J-shaped curve, the basal area followed a bell-shaped pattern. Five types of population structures are revealed. The mean tree density and basal area was 397.3 ***-1 and 31.4 ***-1, respectively. Only 2.8% of the tree species have densities of 〉25 ***^-1 and the percentage dis- tribution of trees show 56.2% in the DBH class 2-10 cm, indicating that the forest is dominated by medium-sized trees. Celtis africana （8.81 ***^-1） and Pouteria adolfi-friederieii （5.13 ***^-1） make the highest contribution to the basal area and species importance value index. The families/species with the highest importance value index are Ulmaceae, Fabacea and Sapotaceae. Species abundance （r2 = 0.32, p 〈0.001） and species richness （P =0.50, p 〈0.001） are positively related with tree density. Tree density is negatively related with elevation （~ = -0.36, p 〈0.001）, slope （r2 =-0.15, p 〈0.001） and aspect （r2 = -0.07, p 〈0.05）. While basal area is negatively related with elevation （r2 =-0.14, p 〈0.001）, it has a

关键词： forest structure basal area stratification topographic factors Afromontane forest

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Land Use Changes of Valleys Based on topographic factors in Beijing Mountainous Regions of China

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Journal of Resources and Ecology 2016年第1期7卷 68-76页

作者：穆松林张义丰 Dhruba Bijaya G.C. 北京市社会科学院北京100101 中国科学院地理科学与资源研究所北京100101

Land use changes in mountainous regions were greatly enhanced as the rapid development of economy due to the expanded population in developing countries. Acting geographically as the basic unit of mountainous regions, valleys are the primary sites of economic activities. Therefore optimization of land use policy in valleys is of critical important to the sustainable development in mountainous regions. On the basis of land use data in 1995 and 2012, this study explored the changes of land use according to the assessment of varied topographic factors （i.e., altitude and slope） in typical valleys of the Beijing mountainous regions, China. Our results showed that the valley is an efficiently geographical unit to evaluate land use changes in mountainous regions. We also found that major land use changes in mountainous regions of Beijing from 1995 to 2012 were the dramatic losses of grassland to the cultivated and construction lands, while most of these changes took place at the altitude of 0-400m and the slope of 6-15~. Considering the ever increasing economic development in Beijing mountainous regions, the increases of the construction and cultivated lands are inevitable, however, the great changes at a steeper slope imply the need to tailor land use structure coming into line with topographic factors, and suggesting ecological barriers and water conservation must be exercised in the developments of these areas.

关键词： land use changes valley topographic factors Beijing mountainous regions

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Assessing vegetation community distribution characteristics and succession stages in mountainous areas hosting coming Winter Olympics Games

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Journal of Mountain Science 2021年第11期18卷 2870-2887页

作者： ZHANG Heng-shuo ZHA Tong-gang YU Yang JI Xiao-dong JESÚS Rodrigo-Comino School of Soil and Water Conservation Beijing Forestry UniversityQinghua East Road 35Beijing 100083China Jixian National Forest Ecosystem Research Network Station CNERNBeijing Forestry UniversityBeijing 100083China Departamento de Análisis Geográfico Regional y Geografía Física Facultad de Filosofía y LetrasCampus Universitario de CartujaUniversity of Granada18071 GranadaSpain

Alpine mountain ecosystem shows strong interactions between abiotic and biotic *** also receive high attention from human activities(natural tourism,trekking,skiing,etc.).However,as the potential disturbance risk areas in alpine mountains are increasing,it is necessary to understand the relationship between environmental factors and plant *** is also the key consideration for the coming international events such as the Winter Olympic Games,which could generate uncontrolled ecosystem issues not previously *** Yin Mountains in Chongli district,Zhangjiakou City,Hebei Province,China will be the core area of the 2022 Winter Olympic *** hypothesize that disturbances will be caused,therefore,the previous relationships between the habitat factors and plant community and the main environmental limiting factors before hosting them must be assessed to design future restoration ***,we used the two-way indicator species analysis(TWINSPAN)and market basket analysis(MBA)for vegetation classification in 91 sampling *** community and relationships among environmental variables(altitude,slope position,aspect,direction,inclination,soil porosity,soil bulk density,organic matter content and soil pH)were investigated through the trend correspondence(DCA)and canonical correspondence analyses(CCA).Also,the TWINSPAN was used to classify the vegetation into 6 different *** analysis showed that i)the spatial variation of soil moisture and the content of soil organic matter are the main factors limiting the development of shrub and herb communities;ii)the distribution of different forest communities was mainly affected by terrain factors(altitude,aspect and slope position);iii)the dynamic changes of vegetation communities in different altitudes were affected by the fluctuation of environmental factors and human disturbance,and the shrubs and herbaceous plants in mid-to-high altitude areas(above 1400 m)generally show the process o

关键词： Vegetation classification topographic factors Community distribution Winter Olympic Games

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Species composition, stand structure, and regeneration status of tree species in dry Afromontane forests of Awi Zone, northwestern Ethiopia

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Ecosystem Health and Sustainability 2019年第1期5卷 199-215,I0020页

作者： Getaneh Gebeyehu Teshome Soromessa Tesfaye Bekele Demel Teketay Center for Environmental Science in Addis Ababa University Addis AbabaEthiopia Ethiopian Environment and Forestry Research Institute Addis AbabaEthiopia Department of Crop Science Botswana University of Agriculture and Natural ResourcesGaboroneBotswana

Species composition,structure,and regeneration status of trees were assessed in five dry Afromontane *** each of the forests,trees having≥5 cm diameter at breast height were identified and measured in 80 quadrats(20×20m^(2)).We compared tree species composition and similarities,stem densities,frequencies,basal area and importance value index of *** index was calculated to 13.3%in the least disturbed and 22.5%in highly disturbed forests.A total of 1,655 individuals representing 38 species and 28 families were *** tree densities varied from 364.1 to 664.1stem ha^(−1) with an average basal area of 20.7m^(2) ha^(−1).The analysis showed significant differences in basal areas of tree species between the least and highly disturbed *** densities ranged from 2000 to 8162.5 stem ha^(−1) and sapling densities ranged from 512.5 to 2562.5 stem ha^(−1).The anthropogenic disturbances revealed high degradation of population structure and regeneration statutes of the trees in the studied forest *** conclusion,the study provided empirical results on the dominance,population structure,importance value and regeneration status of tree species,which would be instrumental for the development of successful rehabilitation strategies for the studied forests.

关键词： Basal area disturbances importance value index regeneration specie composition similarity topographic factors

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InSAR Kalman Filter Phase Unwrapping Algorithm Based on SRTM DEM

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Journal of Earth Science and Engineering 2012年第4期2卷 247-252页

作者： Huadong Hao Guolin Liu Xianlei Chen Zhentan Cao Metrology Verification and Testing Institute Zhoushan Institute of Calibration and Testing for Qualitative and TechnicalSupervision Zhoushan 316021 China Geomatics College Shandong University of Science and Technology Qingdao 266510 China

PU （phase unwrapping） is the key step and important problem in DEM （digital elevation model） extraction and the measurement of surface deformation of InSAR （Interferometric synthetic aperture radar）. The CKFPUA （conventional Kalman filter phase unwrapping algorithm） can obtain reliable results in the flat terrain areas, but it caused error transmission not making the accurate inversion of surface deformation information in the steep terrain. Considering this situation, so it needs to introduce topographic information for guiding phase unwrapping. Here the 90 m resolution DEM data have been used and it is obtained by SRTM （shuttle radar topography mission） measured jointly by NASA （National Aeronautics and Space Administration） and NIMA （National Imaging Mapping Agency） of U.S. Department of Defense. This paper presents a SD-KFPUA （Kalman filter phase unwrapping algorithm） based on SRTM DEM. With SRTM DEM directing InSAR image to implement phase unwrapping, the speed and accuracy are improved. By analyzing with the conventional Kalman filter phase unwrapping algorithms, it is shown that the proposed method can achieve good results in particular to improve unwrapping accuracy in the low coherence region.

关键词： InSAR phase unwrapping Kalman filter topographic factors SRTM DEM.

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