基于两种无人机航拍影像的林窗和林冠提取分析
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摘要
森林冠层和林窗的结构及其时空变化是理解森林生态系统格局、动态变化过程的重要基础。在当前生物多样性监测倍受关注的契机下,如何以合适的手段准确描述林窗面积、分布等特征,并与森林固定样地监测数据有效地结合,更好地回答群落构建的理论问题,使森林群落物种多样性维持机制得到更全面的认识,是目前亟待解决的问题。以鼎湖山南亚热带常绿阔叶林20 hm2固定监测样地为研究对象,基于不同遥感影像提取方法对其林窗和林冠表层数据进行提取分析。结果表明:基于监督分类的提取方法适合RGB波段航片林窗的提取,在林窗分类中,应首先确定林窗高度、边界木与最小面积,不同分类方法差异主要表现在林冠分类中,林窗分类生产者精度和用户精度表现都较为一致。无人机航拍识别率受地形因素影响较大,在地形复杂林地应按坡度分区域进行飞行以降低误差。相对于地面调查,MD4-1000无人机航片的林窗识别率为98.7%;大疆Phantom4无人机航片的林窗识别率为72.3%,影像后期处理数据量小,同样适用于森林林窗定量研究,符合生态学、林业等从业人员对大型样地林窗长期监测的要求。无人机航拍南亚热带森林物种识别难度较大,基于MD4-1000无人机搭载的高分辨率相机,在地势平缓区域优选的4 hm2样地中可识别林冠表层物种数17种,共2 706个个体。搭载高分辨率无人机在降低飞行高度的基础上可进行部分物种识别。应用无人机近地面遥感对森林固定样地进行林冠监测,可为后期群落构建研究提供数据基础,有望从新的研究角度探讨森林群落物种多样性维持机制。
Forest canopy plays a significant role on community biodiversity maintenance,which is the key eco-boundary of forest atmosphere interactions.As an indicator of canopy dynamic,gap is one of the most important factors in maintaining the long-term transformation of ecosystems.In recent times,biodiversity monitoring has been the focus of much attention and study.As such,the problem of how to accurately describe gap features such as size and distribution requires urgent resolution.Furthermore,it is necessary to combine these features with monitoring data from permanent plots in forests in order to bring about solutions for issues relevant to community construction.These solutions will also help researchers achieve a better understanding of the maintenance system of community species diversity in forests.In this study,a practical canopy gap monitoring system was formed on the basis of different image extraction methods using lightweight Unmanned Aerial Vehicles(UAV)and a Geographic Information System(GIS).A 20 ha permanent monitoring plot in Dinghushan,classified as subtropical forest stand in South China,was selected as the data source.The results obtained from different gap extraction methods were scientifically analyzed after a strict classification.Results indicated that the red,green,and blue(RGB)band image classification was applied as the method of extracting remotely sensed images in the monitoring system built in the study.The extracted results were significantly similar to precise field measures.We emphasized penetrability of canopy as a whole in order to quantify the concept depths of the forest gap in subtropical forest stands;we confirmed that the gap could be established in only the lowest height of the canopy.The gap accuracy of supervised classification based on the DJI Phantom UAV was 72.3%,a value lower than the 98.7% attributed to the MD4-1000 UAV.The MD4-1000 is able to fly at specific heights according to geographic states and retrieve relevant tree height data;however,the cost of its use need to be considered.The differences in data obtainment between extraction and actual measurement will also increase while the gradient of plot rises.Therefore,the DJI Phantom UAV is considered suitable for large plot gap extraction due to its accuracy and high efficiency and despite its low-resolution ratio and decreased mission function.Nonetheless,a total of 2706 individuals and 17 species were identified by MD4-1000 UAV.A high-resolution drone is available for partial species identification based on reduced flight altitude.This paper therefore indicates that monitoring forest canopies of permanent plots by using UAV on the basis of near-ground remote sensing is able to provide a database for study in community assembly.It is expected that species diversity maintenance can also be investigated by the inclusion of variants in our study perspective,t is expected that the inclusion of variants in our study perspective could provide further database for study in forest community assembly.Hopefully species diversity maintenance could be investigated by new perspective of near-ground remote sensing.
Forest canopy plays a significant role on community biodiversity maintenance,which is the key eco-boundary of forest atmosphere interactions.As an indicator of canopy dynamic,gap is one of the most important factors in maintaining the long-term transformation of ecosystems.In recent times,biodiversity monitoring has been the focus of much attention and study.As such,the problem of how to accurately describe gap features such as size and distribution requires urgent resolution.Furthermore,it is necessary to combine these features with monitoring data from permanent plots in forests in order to bring about solutions for issues relevant to community construction.These solutions will also help researchers achieve a better understanding of the maintenance system of community species diversity in forests.In this study,a practical canopy gap monitoring system was formed on the basis of different image extraction methods using lightweight Unmanned Aerial Vehicles(UAV)and a Geographic Information System(GIS).A 20 ha permanent monitoring plot in Dinghushan,classified as subtropical forest stand in South China,was selected as the data source.The results obtained from different gap extraction methods were scientifically analyzed after a strict classification.Results indicated that the red,green,and blue(RGB)band image classification was applied as the method of extracting remotely sensed images in the monitoring system built in the study.The extracted results were significantly similar to precise field measures.We emphasized penetrability of canopy as a whole in order to quantify the concept depths of the forest gap in subtropical forest stands;we confirmed that the gap could be established in only the lowest height of the canopy.The gap accuracy of supervised classification based on the DJI Phantom UAV was 72.3%,a value lower than the 98.7% attributed to the MD4-1000 UAV.The MD4-1000 is able to fly at specific heights according to geographic states and retrieve relevant tree height data;however,the cost of its use need to be considered.The differences in data obtainment between extraction and actual measurement will also increase while the gradient of plot rises.Therefore,the DJI Phantom UAV is considered suitable for large plot gap extraction due to its accuracy and high efficiency and despite its low-resolution ratio and decreased mission function.Nonetheless,a total of 2706 individuals and 17 species were identified by MD4-1000 UAV.A high-resolution drone is available for partial species identification based on reduced flight altitude.This paper therefore indicates that monitoring forest canopies of permanent plots by using UAV on the basis of near-ground remote sensing is able to provide a database for study in community assembly.It is expected that species diversity maintenance can also be investigated by the inclusion of variants in our study perspective,t is expected that the inclusion of variants in our study perspective could provide further database for study in forest community assembly.Hopefully species diversity maintenance could be investigated by new perspective of near-ground remote sensing.
引文
Berni J A J,Zarco-Tejada P J,Suarez L and Fereres E.2009.Thermal and Narrowband Multispectral Remote Sensing for Vegetation Monitoring From an Unmanned Aerial Vehicle.Transactions on Geoscience and Remote Sensing,47:722-738.
冯家莉,刘凯,朱远辉,李勇,柳林,蒙琳.2015.无人机遥感在红树林资源调查中的应用.热带地理,35(1):35-42.[Feng Jiali,Liu Kai,Zhu Yuanhui,Li Yong,Liu Lin and Meng Lin.2015.Application of Unmanned Aerial Vehicles to Mangrove Resources Monitoring.Tropical Geography,35(1):35-42.]
Getzin S,Wiegand K and Schoning I.2012.Assessing Biodiversity in Forests Using Very High-Resolution Images and Unmanned Aerial Vehicles.Methods in Ecology and Evolution,3:397-404.
郭庆华,刘瑾,李玉美,翟秋萍,王永财,吴芳芳,胡天宇,万华伟,刘慧明,申文明.2016.生物多样性近地面遥感监测:应用现状与前景展望.生物多样性,24(11):1249-1266.[Guo Qinghua.,Liu Jin,Li Yumei,Zhai Qiuping,Wang Yongcai,Wu Fangfang,Hu Tianyu,Wan Huawei,Liu Huiming and Shen Wenming.2016.Soil Microbial Diversity Observation in China:Current Situation and Future Consideration.Biodiversity Science,24(11):1249-1266.]
Hubbell S P,Foster R B,O'Brien S T,Harms K E,Condit R,Wechsler B,Wright S J and Loo L S.1999.Light-Gap Disturbances,Recruitment Limitation,and Tree Diversity in a Neotropical Forest.Science,283:554-557.
Hunt E R,Hively W D and Fujikawa S J.2010.Acquisition of NIR-Green-Blue Digital Photographs from Unmanned Aircraft for Crop Monitoring.Remote Sensing,2:290-305.
Hunter M O,Keller M,Morton D,Cook B,Lefsky M,Ducey M,Saleska S,De Oliveira R C and Schietti J.2015.Structural Dynamics of Tropical Moist Forest Gaps.Plos One,10(7):1371.
胡理乐,李俊生,吴晓莆,闫伯前,朱教君,罗建武,肖能文.2010.林窗几何特征的测定方法.生态学报,30(7):1911-1919.[Hu Lile,Li Junsheng,Wu Xiaopu,Yan Boqian,Zhu Jiaojun,Luo Jianwu and Xiao Nengwen.2010.Rewiews on Methods of Measuring Geometric Characteristics of Forest Gaps Involving Gap Size,Gap Shape,and the Height of Canopy Trees Surrounding the Gap.Acta Ecologica Sinica,30(7):1911-1919.]
Jonckheere I,Fleck S,Nackaerts K,Muys B,Coppin P,Weiss M and Baret F.2004.Review of Methods for in Situ Leaf Area Index Determination Part I.Theories,Sensors and Hemispherical Photography.Agriculture and Forest Meteorology,121:19-35.
Lima R A F.2005.Gap Size Measurement:the Proposal of a New Field Method.Forest Ecology and Management,214:413-419.
李宇昊,石田.2014.利用航空数码影像的色彩特征估测森林郁闭度.西北林学院学报,29(1):148-154.[Li Yuhao and Shi Tian.2014.Estimating the Canopy Density Through Color Features of Aerial Digital Images.Journal of Northwest Forestry University,29(1):148-154.]
梁晓东,叶万辉,蚁伟民.2001.林窗与生物多样性维持.生态学杂志,20(5):64-68.[Liang Xiaodong,Ye Wanhui and Yi Weiming.2001.Gap Dynamics and the Maintenance of Biodiversity.Chinese Journalof Ecology,20(5):64-68.]
刘峰,谭畅,王红,张江,万颖,龙江平,刘芮希.2015.基于机载激光雷达的中亚热带常绿阔叶林林窗特征.应用生态学报,26(12):3611-3618.[Liu Feng,Tan Chang,Wang Hong,Zhang Jiang,Wan Yin,Long Jiangping and Liu Ruixi.2015.Characterization of Mid-Subtropical Evergreen Broad-Leaved Forest Gap Based on Light Detection and Ranging(Lidar).Chinese Journal of Applied Ecology,26(12):3611-3618.]
刘文平,曹洪麟,刘卫,练琚愉,吴林芳.2011.鼎湖山季风常绿阔叶林不同生境物种多样性研究.安徽农业科学,39(26):16159-16163.[Liu Wenping,Cao Honglin,Liu Wei,Lian Juyu and Wu Linfang.2011.Study on Diversity of Monsoon Evergreen Broad Leaved Forest in Different Kinds of Habitat in Dinghushan.Journal of Anhui Agri.,39(26):16159-16163.]
马克平.2016.生物多样性监测依赖于地面人工观测与先进技术手段的有机结合.生物多样性,24(11):1201-1202.[Ma Keping.2016.Biodiversity Monitoring Relies on the Integration of Human Observation and Automatic Collection of Data with Advanced Equipment and Facilities.Biodiversity Science,24(11):1201-1202.]
Ni W J,Sun G Q,Pang Y,Zhang Z Y,Liu J L,Yang A Q,Wang Y and Zhang D F.2018.Mapping Three-Dimensional Structures of Forest Canopy Using UAV Stereo Imagery:Evaluating Impacts of Forward Overlaps and Image Resolutions with Lidar Data as Reference.IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing,99:1-12.
Ohman K and Lamas T.2005.Reducing Forest Fragmentation in Long-Term Forest Planning by Using the Shape Index.Forest Ecology and Management,212(1):346-357.
Perry D R.1978.A Method of Access into the Crowns of Emergent and Canopy Trees.Biotropica,10:155-157.
彭闪江,黄忠良,周国逸,周小勇,张池,贺握权.2003.鼎湖山林窗形成特征及其对幼树组成.热带亚热带植物学报,11(3):229-235.[Peng Shanjiang,Huang Zhongliang,Zhou Guoyi,Zhou Xiaoyong,Zhan:g Chi and He Woquan.2003.Gap Formation Characteristics and Its Effects on Sapling Composition and Diversity in Dinghushan Biosphere Reserve.Journal of Tropical and Subtropical Botany,111(3):229-235.]
陶欢,李存军,谢春春,周静平,淮贺举,蒋丽雅,李凤涛.2019.基于HSV阈值法的无人机影像变色松树识别.南京林业大学学报(自然科学版),43(3):1-10.[Tao Huan,Li Cunjun,Xie Chunchun.,Zhou Jingping,Huai Heju,Jiang Liya and Li Fengtao.2019.Recognition of Red Attack Pine Trees from UAV Imagery Based on the HSV Threshold Method.Journal of Nanjing Forestry University(Nature Science Edition),43(3):1-10.]
Wang Zhigao,Ye Wanhui,Cao Honglin,Huang Zhongliang,Lian Juyu,LiLin,Wei Shiguang and Sun I Fang.2009.Species-Topography Association in a Species-Rich Subtropical Forest of China.Conservation Genetics,7(10):648-655.
Walter J N and Torquebiau E F.2000.The Computation of Forest Leaf Area Index on Slope Using Fish-Eye Sensors.Ecology,323(9):801-813.
Welles J M and Norman J M.1991.Instrument for Indirect Measurement of Canopy Architecture.Agronomy Journal,83:818-825.
Yamamoto K.2000.Estimation of the Canopy-gap Size Using Two Photographs Taken at Different Heights.Ecological Research,15:203-208.
沈浩,蔡佳宁,李萌姣,陈青,叶万辉,王峥峰,练琚愉,宋亮.2017.中国森林冠层生物多样性监测.生物多样性,25(3):229-236.[Shen Dao,Cai Jianing,Li Mengjiao,Chen Qing,Ye Wanhui,Wang Zhengfeng,Lian Juyu and Song Liang.2015.On Chinese Forest Canopy Biodiversity Monitoring.Biodiversity Science,25(3):229-236.]
隋丹丹,王悦,练据愉,张健,胡健波,欧阳学军,范宗骥,曹洪麟,叶万辉.2017.鼎湖山南亚热带常绿阔叶林林窗分布格局及其成因.生物多样性,25(4):382-392.[Sui Dandan,Wang Yue,Lian Juyu,Zhang Jian,Hu Jianbo Ouyang Xuejun,Fan Zongji,Cao Honglin and Ye Wanhui.2017.Gap Distribution Patterns in Ehe South Subtropical Evergreen Broad-Leaved Forest of Dinghushan.Biodiversity Science,25(4):382-392.]
杨龙,孙中宇,唐光良,林志文,陈燕乔,黎喻,李勇.2016.基于微型无人机遥感的亚热带林冠物种识别.热带地理,36(5):833-839.[Yang Long,Sun Zhongyu,Tang Guangliang,Lin Zhiwen,Chen Yanqiao,Li Yu and Li Yong.2016.Identifying Canopy Species of Subtropical Forest by Lightweight Unmanned Aerial Vehicle Remote Sensing.Tropical Geography,36(5):833-839.]
叶万辉,曹洪麟,黄忠良,练据愉,王志高,李林,魏识广,王章明.2008.鼎湖山南亚热带常绿阔叶林20公顷样地群落特征研究.植物生态学报,32(2):274-286.[Ye Wanhui,Cao Honglin,Huang Zhongliang,Lian Juyu,Wang Zhigao,Li Lin,Wei Shiguang and Wang Zhangming.2008.Community Structure of a 20 ha Lower Subtropical Evergreen Broadleaved Forest Plot in Dinghushan,China.Journal of Plant Ecology,32(2):274-286.]
Zhang J,Hu J B,Lian J Y,Fan Z J,Ouyang X J and Ye W H.2016.Seeing the Forest from Drones:Testing the Potential of Lightweight Drones as a Tool for Long-Term Forest Monitoring.Biological Conservation,198:60-69.
Zhu J,Hu L,Yan Q,Sun Y and Zhang J.2009.A New Calculation Method to Estimate Forest Gap Size.Frontiers of Forestry in China,4:276-282.
Zhang K.2008.Identification of Gaps in Mangrove Forests with Airborne LiDAR.Remote Sensing of Environment,112(5):2309-2325.
冯家莉,刘凯,朱远辉,李勇,柳林,蒙琳.2015.无人机遥感在红树林资源调查中的应用.热带地理,35(1):35-42.[Feng Jiali,Liu Kai,Zhu Yuanhui,Li Yong,Liu Lin and Meng Lin.2015.Application of Unmanned Aerial Vehicles to Mangrove Resources Monitoring.Tropical Geography,35(1):35-42.]
Getzin S,Wiegand K and Schoning I.2012.Assessing Biodiversity in Forests Using Very High-Resolution Images and Unmanned Aerial Vehicles.Methods in Ecology and Evolution,3:397-404.
郭庆华,刘瑾,李玉美,翟秋萍,王永财,吴芳芳,胡天宇,万华伟,刘慧明,申文明.2016.生物多样性近地面遥感监测:应用现状与前景展望.生物多样性,24(11):1249-1266.[Guo Qinghua.,Liu Jin,Li Yumei,Zhai Qiuping,Wang Yongcai,Wu Fangfang,Hu Tianyu,Wan Huawei,Liu Huiming and Shen Wenming.2016.Soil Microbial Diversity Observation in China:Current Situation and Future Consideration.Biodiversity Science,24(11):1249-1266.]
Hubbell S P,Foster R B,O'Brien S T,Harms K E,Condit R,Wechsler B,Wright S J and Loo L S.1999.Light-Gap Disturbances,Recruitment Limitation,and Tree Diversity in a Neotropical Forest.Science,283:554-557.
Hunt E R,Hively W D and Fujikawa S J.2010.Acquisition of NIR-Green-Blue Digital Photographs from Unmanned Aircraft for Crop Monitoring.Remote Sensing,2:290-305.
Hunter M O,Keller M,Morton D,Cook B,Lefsky M,Ducey M,Saleska S,De Oliveira R C and Schietti J.2015.Structural Dynamics of Tropical Moist Forest Gaps.Plos One,10(7):1371.
胡理乐,李俊生,吴晓莆,闫伯前,朱教君,罗建武,肖能文.2010.林窗几何特征的测定方法.生态学报,30(7):1911-1919.[Hu Lile,Li Junsheng,Wu Xiaopu,Yan Boqian,Zhu Jiaojun,Luo Jianwu and Xiao Nengwen.2010.Rewiews on Methods of Measuring Geometric Characteristics of Forest Gaps Involving Gap Size,Gap Shape,and the Height of Canopy Trees Surrounding the Gap.Acta Ecologica Sinica,30(7):1911-1919.]
Jonckheere I,Fleck S,Nackaerts K,Muys B,Coppin P,Weiss M and Baret F.2004.Review of Methods for in Situ Leaf Area Index Determination Part I.Theories,Sensors and Hemispherical Photography.Agriculture and Forest Meteorology,121:19-35.
Lima R A F.2005.Gap Size Measurement:the Proposal of a New Field Method.Forest Ecology and Management,214:413-419.
李宇昊,石田.2014.利用航空数码影像的色彩特征估测森林郁闭度.西北林学院学报,29(1):148-154.[Li Yuhao and Shi Tian.2014.Estimating the Canopy Density Through Color Features of Aerial Digital Images.Journal of Northwest Forestry University,29(1):148-154.]
梁晓东,叶万辉,蚁伟民.2001.林窗与生物多样性维持.生态学杂志,20(5):64-68.[Liang Xiaodong,Ye Wanhui and Yi Weiming.2001.Gap Dynamics and the Maintenance of Biodiversity.Chinese Journalof Ecology,20(5):64-68.]
刘峰,谭畅,王红,张江,万颖,龙江平,刘芮希.2015.基于机载激光雷达的中亚热带常绿阔叶林林窗特征.应用生态学报,26(12):3611-3618.[Liu Feng,Tan Chang,Wang Hong,Zhang Jiang,Wan Yin,Long Jiangping and Liu Ruixi.2015.Characterization of Mid-Subtropical Evergreen Broad-Leaved Forest Gap Based on Light Detection and Ranging(Lidar).Chinese Journal of Applied Ecology,26(12):3611-3618.]
刘文平,曹洪麟,刘卫,练琚愉,吴林芳.2011.鼎湖山季风常绿阔叶林不同生境物种多样性研究.安徽农业科学,39(26):16159-16163.[Liu Wenping,Cao Honglin,Liu Wei,Lian Juyu and Wu Linfang.2011.Study on Diversity of Monsoon Evergreen Broad Leaved Forest in Different Kinds of Habitat in Dinghushan.Journal of Anhui Agri.,39(26):16159-16163.]
马克平.2016.生物多样性监测依赖于地面人工观测与先进技术手段的有机结合.生物多样性,24(11):1201-1202.[Ma Keping.2016.Biodiversity Monitoring Relies on the Integration of Human Observation and Automatic Collection of Data with Advanced Equipment and Facilities.Biodiversity Science,24(11):1201-1202.]
Ni W J,Sun G Q,Pang Y,Zhang Z Y,Liu J L,Yang A Q,Wang Y and Zhang D F.2018.Mapping Three-Dimensional Structures of Forest Canopy Using UAV Stereo Imagery:Evaluating Impacts of Forward Overlaps and Image Resolutions with Lidar Data as Reference.IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing,99:1-12.
Ohman K and Lamas T.2005.Reducing Forest Fragmentation in Long-Term Forest Planning by Using the Shape Index.Forest Ecology and Management,212(1):346-357.
Perry D R.1978.A Method of Access into the Crowns of Emergent and Canopy Trees.Biotropica,10:155-157.
彭闪江,黄忠良,周国逸,周小勇,张池,贺握权.2003.鼎湖山林窗形成特征及其对幼树组成.热带亚热带植物学报,11(3):229-235.[Peng Shanjiang,Huang Zhongliang,Zhou Guoyi,Zhou Xiaoyong,Zhan:g Chi and He Woquan.2003.Gap Formation Characteristics and Its Effects on Sapling Composition and Diversity in Dinghushan Biosphere Reserve.Journal of Tropical and Subtropical Botany,111(3):229-235.]
陶欢,李存军,谢春春,周静平,淮贺举,蒋丽雅,李凤涛.2019.基于HSV阈值法的无人机影像变色松树识别.南京林业大学学报(自然科学版),43(3):1-10.[Tao Huan,Li Cunjun,Xie Chunchun.,Zhou Jingping,Huai Heju,Jiang Liya and Li Fengtao.2019.Recognition of Red Attack Pine Trees from UAV Imagery Based on the HSV Threshold Method.Journal of Nanjing Forestry University(Nature Science Edition),43(3):1-10.]
Wang Zhigao,Ye Wanhui,Cao Honglin,Huang Zhongliang,Lian Juyu,LiLin,Wei Shiguang and Sun I Fang.2009.Species-Topography Association in a Species-Rich Subtropical Forest of China.Conservation Genetics,7(10):648-655.
Walter J N and Torquebiau E F.2000.The Computation of Forest Leaf Area Index on Slope Using Fish-Eye Sensors.Ecology,323(9):801-813.
Welles J M and Norman J M.1991.Instrument for Indirect Measurement of Canopy Architecture.Agronomy Journal,83:818-825.
Yamamoto K.2000.Estimation of the Canopy-gap Size Using Two Photographs Taken at Different Heights.Ecological Research,15:203-208.
沈浩,蔡佳宁,李萌姣,陈青,叶万辉,王峥峰,练琚愉,宋亮.2017.中国森林冠层生物多样性监测.生物多样性,25(3):229-236.[Shen Dao,Cai Jianing,Li Mengjiao,Chen Qing,Ye Wanhui,Wang Zhengfeng,Lian Juyu and Song Liang.2015.On Chinese Forest Canopy Biodiversity Monitoring.Biodiversity Science,25(3):229-236.]
隋丹丹,王悦,练据愉,张健,胡健波,欧阳学军,范宗骥,曹洪麟,叶万辉.2017.鼎湖山南亚热带常绿阔叶林林窗分布格局及其成因.生物多样性,25(4):382-392.[Sui Dandan,Wang Yue,Lian Juyu,Zhang Jian,Hu Jianbo Ouyang Xuejun,Fan Zongji,Cao Honglin and Ye Wanhui.2017.Gap Distribution Patterns in Ehe South Subtropical Evergreen Broad-Leaved Forest of Dinghushan.Biodiversity Science,25(4):382-392.]
杨龙,孙中宇,唐光良,林志文,陈燕乔,黎喻,李勇.2016.基于微型无人机遥感的亚热带林冠物种识别.热带地理,36(5):833-839.[Yang Long,Sun Zhongyu,Tang Guangliang,Lin Zhiwen,Chen Yanqiao,Li Yu and Li Yong.2016.Identifying Canopy Species of Subtropical Forest by Lightweight Unmanned Aerial Vehicle Remote Sensing.Tropical Geography,36(5):833-839.]
叶万辉,曹洪麟,黄忠良,练据愉,王志高,李林,魏识广,王章明.2008.鼎湖山南亚热带常绿阔叶林20公顷样地群落特征研究.植物生态学报,32(2):274-286.[Ye Wanhui,Cao Honglin,Huang Zhongliang,Lian Juyu,Wang Zhigao,Li Lin,Wei Shiguang and Wang Zhangming.2008.Community Structure of a 20 ha Lower Subtropical Evergreen Broadleaved Forest Plot in Dinghushan,China.Journal of Plant Ecology,32(2):274-286.]
Zhang J,Hu J B,Lian J Y,Fan Z J,Ouyang X J and Ye W H.2016.Seeing the Forest from Drones:Testing the Potential of Lightweight Drones as a Tool for Long-Term Forest Monitoring.Biological Conservation,198:60-69.
Zhu J,Hu L,Yan Q,Sun Y and Zhang J.2009.A New Calculation Method to Estimate Forest Gap Size.Frontiers of Forestry in China,4:276-282.
Zhang K.2008.Identification of Gaps in Mangrove Forests with Airborne LiDAR.Remote Sensing of Environment,112(5):2309-2325.
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