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Biomass and net primary productivity of mangrove communities along the Oligohaline zone of Sundarbans, Bangladesh

Forest Ecosystems 2017年第4期4卷 264-272页

作者： Md. Kamruzzaman Shamim Ahmed akira osawa Laboratory of Ecosystem Production and Dynamics Graduate School of Global Environmental Studies Kyoto University Kyoto 606-8501 Japan Forestry and Wood Technology Discipline Khulna University Khulna 9208 Bangladesh

Background： The article presents the first estimates of biomass and productivity for mangrove forests along the Oligohaline zone of the Sundarbans Reserve Forest （SRF）, Bangladesh. This study was conducted overone year from March 2016 to April 20] 7. Stand structure, above and below-ground biomass changes, and litterfall production were measured within a 2100 m2 sample plot. Methods： All trees in the study plots were numbered and height （H） and diameter at breast height （DBH） were measured. Tree height （H） and DBH for each tree were measured in March 2016 and 2017. We apply the above and belowground biomass equation for estimating the biomass of the mangrove tree species （Chave et al. Oecologia 145：87-99, 2005; Komiyama et al. J Trop Ecol 21：471-477, 2005）. Litterfall was collected using 1-mm mesh litter traps with collection area of 0.42 m2. Net Primary Production （NPP） was estimated by the summation method of Ogawa Primary productivity of Japanese forests： productivity of terrestrial communities, JIBP synthesis （1977） and Matsuura and Kajimoto Carbon dynamics of terrestrial ecosystem： Systems approach to global environment （2013）. Results： Heritiero fomes has maintained its dominance of the stand and also suffered the highest tree mortality （2.4%） in the suppressed crown class. The total above-ground biomass （AGB） and below-ground biomass （BGB） of the studied stand was ]54.8 and 84.2 ***-1, respectively. Among the total biomass of the trees, 64.8% was allocated to AGB and 35.2% to BGB. In case of species-wise contribution of biomass allocation, Avicennia officinalis showed the highest score and Aglaia cucullota the lowest. Mean annual total litterfall was 10.1 Mg-ha ***-1, with the maximum litterfall in winter or dry season and late summer or rainy season. The mean AGB increment and above-ground net primary productivity （AGNPP） were 7.1 and 17.2 ***-1, respectively. Total net primary productivity （NPP） was estimated to be 21.0 *** Lyr-1 over the observ

关键词： Primary production Litterfall Monthly pattern Biomass carbon Species wise contribution Sundarbans

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Land use patterns and tree species diversity in the Volta Geological Unit, Togo

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Journal of Mountain Science 2019年第8期16卷 1869-1882页

作者： FOLEGA Fousseni ATAKPAMA Wouyo WALA Kperkouma MUKETE Beckline SHOZO Shibata akira osawa ZHAO Xiu-hai AKPAGANA Koffi Geomatic and Ecosystems Modeling/Laboratory of botany and Plant Ecology Faculty of SciencesUniversity of LomeLome01BP1515Togo Key Laboratory for Forest Resources&Ecosystem Processes Beijing Forestry UniversityBeijing 100083China Graduate School of Global Environmental Studies Kyoto UniversityKyoto 606-8501Japan Department of Forest Management Beijing Forestry UniversityBeijing 100083China

The application of remote sensing in understanding tree species structural diversity and land use patterns relationship is imperative for reforestation and biodiversity conservation efforts. This study assesses land use patterns and tree species structural diversity in previously reforested hilly sandstone regions of northern Togo. The physical height, and diameter at breast height(DBH) more than 5 cm of all tree species in each given plot were measured in summer 2017. A total of 75 plots of 900 m^2 installed along the toposequence were recorded. In addition, a semi-supervised classification of Landsat 8 images in January of 2018, was also used to classify the land use patterns. 36 tree species and 19 families were recorded for the entire study area. Meanwhile, 19 tree species and 15 families were recorded for the previously afforested zones. The most abundant species included the Sterculiaceae, Zygophyllaceae, Meliaceae, and Mimosaceae. The trees stand structure represented 8.61 ± 0.57 m, 11.28 ± 1.76 cm, and 0.018 ± 0.009 m^2 per hectare for height, diameter and basal area respectively. Major land use patterns were tree and shrub savannahs, parklands and croplands which represented over 60% of the landscape. It is necessary to examine the regeneration and vegetative multiplication potentials of the most frequent and abundant tree species for any eventual future afforestation programs in these hilly sandstone regions of northern Togo.

关键词： Ecological diversity Land use Ecological restoration Forest degradation Togo

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High-quality micro-shape fabrication of monocrystalline diamond by nanosecond pulsed laser and acid cleaning

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International Journal of Extreme Manufacturing 2022年第2期4卷 173-183页

作者： Yasuhiro Okamoto Tubasa Okubo Atsuya Kajitani akira Okada Graduate School of Natural Science and Technology Okayama UniversityOkayamaJapan

The flat plane of small surface roughness below 0.1μm average roughness was obtained for monocrystalline diamond by nanosecond pulsed laser irradiation of 1060 nm and post-process acid cleaning,at a laser fluence around the material removal threshold *** glossy and flat plane at the bottom of the micro-groove was parallel to the top surface of the specimen,although the round beam of Gaussian mode was irradiated in the direction perpendicular to the top surface of *** square beam of top-hat mode produced a shallower micro-groove with a wider,flatter bottom compared with the round beam in Gaussian *** creation method of the flat plane with small surface roughness was discussed in the arrangement strategy of linear micro-grooving by the square beam of top-hat *** side-by-side repetition of linear micro-grooving did not create a flat plane with constant ***,a two-step scanning method was proposed in order to overcome the problem in the normal side-by-side repetition of liner ***-removal areas were partly retained between the processing lines in the first step,and the laser scanning was conducted on the retained area in the second *** newly proposed two-step scanning method was practical and useful to create a widely flat plane with small surface roughness,and the two-step scanning method provided superior control over the micro-groove *** proposed method can reduce the surface roughness in addition to the shape creation of monocrystalline diamond,and it can be used as a high-quality micro-shape fabrication method of monocrystalline diamond.

关键词： monocrystalline diamond nanosecond pulsed laser flat surface smooth surface micro-grooving

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