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Individual tree extraction from terrestrial laser scanning data via graph pathing

Forest Ecosystems 2021年第4期8卷 903-913页

作者： Di Wang Xinlian Liang Gislain II Mofack Olivier Martin-Ducup Department of Remote Sensing Science and Technology School of Electronic EngineeringXidian University710077 Xi’anChina State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University430079 WuhanChina Department of Remote Sensing and Photogrammetry Finnish Geospatial Research Institute02430 MasalaFinland Plant Systematics and Ecology Laboratory Higher Teacher’s Training CollegeUniversity of Yaounde IBP 337 YaoundeCameroon AMAP Univ MontpellierIRDCNRSCIRADINRAEF-34000 MontpellierFrance

Background:Individual tree extraction from terrestrial laser scanning(TLS)data is a prerequisite for tree-scale estimations of forest biophysical *** task currently is undertaken through laborious and time-consuming manual assistance and quality *** study presents a new fully automatic approach to extract single trees from large-area TLS *** data-driven method operates exclusively on a point cloud graph by path finding,which makes our method computationally efficient and universally applicable to data from various forest ***:We demonstrated the proposed method on two openly available ***,we achieved state-of-the-art performance on locating single trees on a benchmark dataset by significantly improving the mean accuracy by over 10% especially for difficult forest ***,we successfully extracted 270 trees from one hectare temperate *** validation resulted in a mean Intersection over Union(mIoU)of 0.82 for single crown segmentation,which further led to a relative root mean square error(RMSE%)of 21.2% and 23.5% for crown area and tree volume estimations,***:Our method allows automated access to individual tree level information from TLS point *** proposed method is free from restricted assumptions of forest *** is also computationally efficient with an average processing time of several seconds for one million *** is expected and hoped that our method would contribute to TLS-enabled wide-area forest qualifications,ranging from stand volume and carbon stocks modelling to derivation of tree functional traits as part of the global ecosystem understanding.

关键词： Point cloud Segmentation Tree extraction Graph pathing

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Selective harvesting at rational intervals promotes carbon sequestration in temperate coniferous and broad-leaved mixed forests in China

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Journal of Forestry Research 2021年第3期32卷 1025-1033页

作者： Jihua Hou Junxia Tian Li Xu Zihao Zhang Zhi Chen Nianpeng He Beijing Key Laboratory of Forest Resources and Ecosystem Processes Beijing Forestry UniversityBeijing 100083People’s Republic of China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101People’s Republic of China college of Resources and Environment University of Chinese Academy of SciencesBeijing 100049People’s Republic of China Key Laboratory of Vegetation Ecology Ministry of EducationNortheast Normal UniversityChangchun 130024People’s Republic of China

Evidence-based selective cutting at prescribed intervals as part of good forest management can enhance the carbon sequestration capacity of the *** effect of forest management on carbon sequestration has,however,not been ***,carbon content of various organs was measured for 323 tree species,247 shrub species,and233 herb species in seven temperate coniferous and broadleaved mixed forests that were subjected to selective cutting with restoration durations of 100,55,45,36,25,14,and6 years to explore dynamic changes in carbon *** results showed that biomass carbon allocation in different organs followed a pattern:trunk>root>branch>leaf for all *** longer restoration durations,more carbon accumulated in different organs and in ***,when the restoration duration exceeded 50 years,carbon storage in ecosystem was larger than that in primary forests with 100-year cutting intervals,suggesting that a reasonable selective cutting interval can increase forest carbon *** diameter at breast height(DBH)and forest carbon storage were significantly positively correlated,and carbon storage of selectively cut forests exceeded that of primary forests when the stand mean DBH exceeded 15.66 ***,mean DBH of forests can be an indicator for combining sustainable forest management and forest carbon ***,the classic coefficients of 0.45 and 0.50 used to estimate carbon sequestration underestimated values by 2.65%and overestimated by 8.16%,respectively,in comparison with the measured carbon content from different plant organs.

关键词： Selective cutting Forests Diameter at breast height Carbon Storage Management Restoration

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Seasonal distribution of increased precipitation in maternal environments influences offspring performance of Potentilla tanacetifolia in a temperate steppe ecosystem

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Journal of Plant Ecology 2019年第4期12卷 742-750页

作者： Yang Li Longyu Hou Bing Song Shiqiang Wan Xiaoqin Sun Linghao Li Xi’an Botanical Garden of Shaanxi Province Institute of Botany of Shaanxi ProvinceXi’an 710061China Shaanxi Engineering Research Centre for Conservation and Utilization of Botanical Resources Xi’an 710061China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China college of Life Science Hebei UniversityBaoding 071000China State Key Laboratory of Earth Surface Processes and Resource Ecology(ESPRE) Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China

Aims Precipitation is predicted to increase in arid and semiarid regions under climate change,with greater changes in intra-and interannual distribution in the *** a major limiting factor in these regions,changes in precipitation undoubtedly influence plant growth and ***,how the temporal shifts in pre-cipitation will impact plant populations are *** A 3-year field experiment and a greenhouse experiment were conducted in a temperate grassland in northern China to examine the impacts of seasonal(spring and summer)increased precipitation on offspring performance of a common species,Potentilla *** Findings Our results showed that the amounts and timing of increased precipitation both played important roles in regulating offspring performance of *** in the temperate steppe *** precipitation in spring at maternal stage stimulated seed production,germination percentage and seedling biomass,whereas increased precipitation in summer at maternal stage stimulated seedling *** timing of increased precipitation influenced seed attributes,whereas the amount of increased precipitation influenced offspring seedling *** results indicate that population development of *** may be underestimated under future increased precipitation regime,if the transgenerational effect is not taken into account.

关键词： precipitation regime seed traits seedling growth semiarid grassland

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Dynamics of carbon stocks in soils and detritus across chronosequences of different forest types in the Pacific Northwest,USA

Dynamics of carbon stocks in soils and detritus across chron...

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“全国第五届青年植物生态学学术研讨会”暨“第二届植物生理生态学学术研讨会”

作者： OSBERT J.SUN JOHN CAMPBELL BEVERLY E.LAW VERNON WOLF Laboratory of Quantitative Vegetation Ecology Institute of Botanythe Chinese Academy of Sciences Beijing 100093 China Department of Forest Science College of Forestry Oregon State UniversityCorvallisOR 97331 USA

We investigated variation in carbon stock in soils and detritus (forest floor and woody debris) in chronosequences that represent the range of forest types in the US Pacific Northwest Stands range in age from 600 years. Soil carbon, to a depth of 100cm, was highest in coastal Sitka spruce/western hemlock forests (36 ±10kgCm-2) and lowest in semiarid ponderosa pine forests (7 ±10kg Cm-2). Forests distributed across the Cascade Mountains had intermediate values between 10 and 25kg Cm-2. Soil carbon stocks were best described as a linear function of net primary productivity (r2 = 0.52), annual precipitation (r2 = 0.51), and a power function of forest floor mean residence time (r2 = 0.67). The highest rates of soil and detritus carbon turnover were recorded on mesic sites of Douglas-fir/western hemlock forests in the Cascade Mountains with lower rates in wetter and drier habitats, similar to the pattern of site productivity. The relative contribution of soil and detritus carbon to total ecosystem carbon decreased as a negative exponential function of stand age to a value of -35% between 150 and 200 years across the forest types. These age-dependent trends in the portioning of carbon between biomass and necromass were not different among forest types. Model estimates of soil carbon storage based on decomposition of legacy carbon and carbon accumulation following stand-replacing disturbance showed that soil carbon storage reached an asymptote between 150 and 200 years, which has significant implications to modeling carbon dynamics of the temperate coniferous forests following a stand-replacing disturbance.

关键词： carbon stock chronosequence climate disturbance forest ecosystem soil carbon

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Degree of shade tolerance shapes seasonality of chlorophyll, nitrogen and phosphorus levels of trees and herbs in a temperate deciduous forest

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Journal of Forestry Research 2024年第4期35卷 60-72页

作者： Jiajia Zeng Fan Liu Yuan Zhu Jiayi Li Ying Ruan Xiankui Quan Chuankuan Wang Xingchang Wang Aulin college Northeast Forestry UniversityHarbin 150040People’s Republic of China Center for Ecological Research Northeast Forestry UniversityHarbin 150040People’s Republic of China Key Laboratory of Agricultural Water Resources Center for Agricultural Resources ResearchInstitute of Genetics and Developmental BiologyChinese Academy of SciencesShijiazhuang 050021People’s Republic of China Institute of Applied Ecology Chinese Academy of SciencesShenyang 110016People’s Republic of China Key Laboratory of Sustainable Forest Ecosystem Management Ministry of EducationNortheast Forestry UniversityHarbin 150040People’s Republic of China

Forest productivity is closely linked to seasonal variations and vertical differentiation in leaf ***,leaf structural and chemical traits variation among co-existing species,and plant functional types within the canopy are poorly *** this study,the seasonality of leaf chlorophyll,nitrogen(N),and phosphorus(P)were quantified vertically along the canopy of four major tree species and two types of herbs in a temperate deciduous *** role of shade tolerance in shaping the seasonal variation and vertical differentiation was *** the entire season,chlorophyll content showed a distinct asymmetric unimodal pattern for all species,with greater chlorophyll levels in autumn than in spring,and the timing of peak chlorophyll per leaf area gradually decreased as shade tolerance *** a:b ratios gradually decreased with increasing shade *** N and P contents sharply declined during leaf expansion,remained steady in the mature stage and decreased again during leaf *** the seasons,the lower canopy layer had significantly higher chlorophyll per leaf mass but not chlorophyll per leaf area than the upper canopy layer regardless of degree of shade ***,N and P per leaf area of intermediate shade-tolerant and fully shade-tolerant tree species were significantly higher in the upper canopy than in the *** variations in N:P ratios suggest changes in N or P *** findings indicate that shade tolerance is a key feature shaping inter-specific differences in leaf chlorophyll,N,and P contents as well as their seasonality in temperate deciduous forests,which have significant implications for modeling leaf photosynthesis and ecosystem production.

关键词： Leaf traits Leaf nutrients Seasonal variations Chlorophyll Nitrogen Phosphorus Shade tolerance Canopy layers

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Extreme fire weather is the major driver of severe bushfires in southeast Australia

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Science Bulletin 2022年第6期67卷 655-664,M0004页

作者： Bin Wang Allan C.Spessa Puyu Feng Xin Hou Chao Yue Jing-Jia Luo Philippe Ciais Cathy Waters Annette Cowie Rachael H.Nolan Tadas Nikonovas Huidong Jin Henry Walshaw Jinghua Wei Xiaowei Guo De Li Liu Qiang Yu State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F UniversityYangling 712100China New South Wales Department of Primary Industries Wagga Wagga Agricultural InstituteWagga Wagga 2650Australia Department of Geography College of ScienceSwansea UniversitySingleton ParkSwansea SA28PPUK college of Land Science and Technology China Agricultural UniversityBeijing 100193China college of Natural Resources and Environment Northwest A&F UniversityYangling 712100China Institute for Climate and Application Research(ICAR)/Key Laboratory of Meteorological Disaster of Ministry of Education(KLME) Nanjing University of Information Science and TechnologyNanjing 210044China Laboratoire des Sciences du Climat et de l'Environnement CEA-CNRS-UVSQGif sur Yvette F-91191France New South Wales Department of Primary Industries Dubbo 2830Australia New South Wales Department of Primary Industries Armidale 2351Australia School of Environmental and Rural Science University of New EnglandArmidale 2351Australia Hawkesbury Institute for the Environment Western Sydney UniversityPenrith 2751Australia CSIRO Data61 Canberra 2601Australia Python Charmers Pty Ltd Hawthorn 3122Australia Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810008China Climate Change Research Centre University of New South WalesSydney 2052Australia college of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

In Australia,the proportion of forest area that burns in a typical fire season is less than for other vegetation ***,the 2019-2020 austral spring-summer was an exception,with over four times the previous maximum area burnt in southeast Australian temperate *** forest fires have extensive socio-economic,human health,greenhouse gas emissions,and biodiversity impacts due to high fire intensities.A robust model that identifies driving factors of forest fires and relates impact thresholds to fire activity at regional scales would help land managers and fire-fighting agencies prepare for potentially hazardous fire in ***,we developed a machine-learning diagnostic model to quantify nonlinear relationships between monthly burnt area and biophysical factors in southeast Australian forests for 2001-2020 on a 0.25°grid based on several biophysical parameters,notably fire weather and vegetation *** model explained over 80%of the variation in the burnt *** identified that burnt area dynamics in southeast Australian forest were primarily controlled by extreme fire weather,which mainly linked to fluctuations in the Southern Annular Mode(SAM)and Indian Ocean Dipole(IOD),with a relatively smaller contribution from the central Pacific El Niño Southern Oscillation(ENSO).Our fire diagnostic model and the non-linear relationships between burnt area and environmental covariates can provide useful guidance to decision-makers who manage preparations for an upcoming fire season,and model developers working on improved early warning systems for forest fires.

关键词： Remote sensing Forest fires Climate drivers Burnt area modelling Machine learning Southeast Australia

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Two response patterns to negative environmental changes:Cases from Populus and Metasequoia

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Global Geology 2023年第2期26卷 63-73页

作者： ZHANG Yi XIONG Zhifeng GUO Shuangxing college of Paleontology Shenyang Normal UniversityShenyang 110034China Key Laboratory for Evolution of Past Life in Northeast Asia Ministry of Natural ResourcesShenyang 110034China Nanjing Institute of Geology and Palaeontology Chinese Academy of SciencesNanjing 210008China

Traditionally,plant distribution is thought to be closely related to environmental *** recently,it is found that Populus,quite different from other plant taxa,adapted to negative environmental changes,and successfully migrated to different climate zones from its origin places of warm temperate ***,Metasequoia is gradually tending to extinction from the Miocene to *** on above contrary cases,two response patterns of plant to negative environmental changes are *** is active adaptation represented by Populus,the other is passive adaptation represented by *** plants of passive strategy characterized for desert prevention might be easily replaced by those of active strategy characterized for desert *** growing plants,such as Populus with characteristics of drought and salt tolerance,wind and sand resistance,are selected in Tarim Basin in southern Xinjiang,China,as a good example of desert utilization in the construction of new highways and towns,not only serve as farmland shelterbelt in sandy *** addition,Populus with high-altitude and cold adaptation has also been selected as an ideal tree planted in ***,the idea of using Populus as one of the preferred pioneer trees to colonize Mars is proposed.

关键词： active adaptation passive adaptation Populus Metasequoia deserts Mars

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A high-quality,phased genome assembly of broomcorn millet reveals the features of its subgenome evolution and 3D chromatin organization

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Plant Communications 2023年第3期4卷 3-6页

作者： Zhiheng Wang Shihui Huang Zhengyue Yang Jinsheng Lai Xiang Gao Junpeng Shi State Key Laboratory of Biocontrol School of AgricultureSun Yat-sen UniversityShenzhen 518107China School of Biomedical Sciences Faculty of MedicineThe Chinese University of Hong KongHong Kong SARChina college of Agronomy and Biotechnology China Agricultural UniversityBeijing 100193China State Key Laboratory of Plant Physiology and Biochemistry&National Maize Improvement Center Department of Plant Genetics and BreedingChina Agricultural UniversityBeijing 100193China These authors contributed equally to this article

Dear Editor,Grasses of the genus Panicumgrowin natural and agricultural ecosystems worldwide and include about 450 species distributed throughout tropical and temperate *** Panicumgrasses remain unexploited,with the exceptions of broomcorn millet(***)(Shi et al.,2019;Zou et al.,2019),switchgrass(***)(Lovell et al.,2021),Hall’s panicgrass(***)(Lovell et al.,2018),and a few other species that have been successfully domesticated into staple,forage,and energy *** millet(2n=4x=36)is probably one of the earliest domesticated grain crops,originating in North China around 10000 years ago.

关键词： evolution crops temperate

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Biomass allocation between leaf and stem regulates community-level plant nutrient resorption efficiency response to nitrogen and phosphorus additions in a temperate wetland of Northeast China

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Journal of Plant Ecology 2021年第1期14卷 58-66页

作者： Yun Zhang Gui-Sheng Yang Fu-Xi Shiu Rong Mao Key Laboratory of National Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of ForestryJiangxi Agricullural UniversityNanchang 330045China Wuyishanxipo Observation and Research Station of Forest Ecosystem Zixi 335300China Environment and Plant Protection Institute Chinese Academy of Tropical Agricultural ScienceHaikou 571101China

Aims Nutrient resorption is a crucial component of plant nutrient use strategy,yet the controls on the responses of community-level nutrient resorption to altered nutrient availability remain ***,we addressed two questions:(1)Did leaf and stem nutrient resorption respond consistently to increased nutrient availability?(2)Was community-level plant nutrient resorption response after nutrient enrichment driven by the intraspecific plasticity in plant nutrient resorption or by altered species composition?Methods We investigated the changes in aboveground biomass,and leaf and stem nutrient resorption of individual species after 3-year nitrogen(N)and phosphorus(P)additions,and assessed community-level nutrient resorption response to 3-year nutrient additions in a graminoid-dominated temperate wetland,Northeast *** Findings For both leaves and stems,N and P additions did not affect nutrient resorption efficiency,but they decreased respective nutrient resorption ***,community-level N and P resorption proficiency declined with respective nutrient ***-level N and P resorption efficiency was reduced by N addition primarily due to altered community composition and declined leaf:stem *** results suggest that leaf and stem nutrient resorption processes exhibit consistent responses to increasing nutrient availability in the temperate *** findings highlight the importance of altered species composition and biomass allocation between leaf and stem in driving community-level nutrient resorption response to nutrient enrichment.

关键词： leaf:stem ratio nutrient enrichment nutrient resorption proficiency nutrient use strategy species composition

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Construction and genietic tansformation of RNA interference vectors for rice black-streaked dwarf virus

Construction and genietic tansformation of RNA interference ...

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山东植物生理学会第七次代表大会暨植物生物学与现代农业研讨会

作者： ZHANG Gui-Lin LI Zhen WANG Qin-Guo LIU Xu YAO Fang-Yin WANG Ying-Ying 刘炜 college of Life Science Shandong Normal University High-Tech Research Center Shandong Academy of Agricultural Sciences/Shandong Provincial Key Laboratory of Genetic ImprovementEcology and Physiology of CropsShandong Province

Rice Black-Streaked Dwarf(RBSDD),caused by rice black-streaked dwarf virus(RBSDV),is a kind of serious viral disease in temperate rice-grown *** usually leads to severe rice growth abnormalities, such as severe dwarfing,more ineffective tillerings with almost no heading,and has made a enormous threat to rice production and *** interference(RNAi),as a newly developed gene-silence tool,

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