Identifying and quantifying the abundance of economically important palms in tropical moist forest using UAV imagery

Sustainable management of non-timber forest products such as palm fruits is crucial for the long-term conservation of intact forest. A major limitation to expanding sustainable management of palms has been the need for precise information about the resources at scales of tens to hundreds of hectares, while typical ground-based surveys only sample small areas. In recent years, small unmanned aerial vehicles (UAVs) have become an important tool for mapping forest areas as they are cheap and easy to transport, and they provide high spatial resolution imagery of remote areas. We developed an object-based classification workflow for RGB UAV imagery which aims to identify and delineate palm tree crowns in the tropical rainforest by combining image processing and GIS functionalities using color and textural information in an integrative way to show one of the potential uses of UAVs in tropical forests. Ten permanent forest plots with 1170 reference palm trees were assessed from October to December 2017. The results indicate that palm tree crowns could be clearly identified and, in some cases, quantified following the workflow. The best results were obtained using the random forest classifier with an 85% overall accuracy and 0.82 kappa index.Publisher PDFPeer reviewe

Extending our scientific reach in arboreal ecosystems for research and management

The arboreal ecosystem is vitally important to global and local biogeochemical processes, the maintenance of biodiversity in natural systems, and human health in urban environments. The ability to collect samples, observations, and data to conduct meaningful scientific research is similarly vital. The primary methods and modes of access remain limited and difficult. In an online survey, canopy researchers (n = 219) reported a range of challenges in obtaining adequate samples, including ∼10% who found it impossible to procure what they needed. Currently, these samples are collected using a combination of four primary methods: (1) sampling from the ground; (2) tree climbing; (3) constructing fixed infrastructure; and (4) using mobile aerial platforms, primarily rotorcraft drones. An important distinction between instantaneous and continuous sampling was identified, allowing more targeted engineering and development strategies. The combination of methods for sampling the arboreal ecosystem provides a range of possibilities and opportunities, particularly in the context of the rapid development of robotics and other engineering advances. In this study, we aim to identify the strategies that would provide the benefits to a broad range of scientists, arborists, and professional climbers and facilitate basic discovery and applied management. Priorities for advancing these efforts are (1) to expand participation, both geographically and professionally; (2) to define 2–3 common needs across the community; (3) to form and motivate focal teams of biologists, tree professionals, and engineers in the development of solutions to these needs; and (4) to establish multidisciplinary communication platforms to share information about innovations and opportunities for studying arboreal ecosystems

Identifying and quantifying the abundance of economically important palms in tropical moist forest using UAV imagery

Sustainable management of non-timber forest products such as palm fruits is crucial for the long-term conservation of intact forest. A major limitation to expanding sustainable management of palms has been the need for precise information about the resources at scales of tens to hundreds of hectares, while typical ground-based surveys only sample small areas. In recent years, small unmanned aerial vehicles (UAVs) have become an important tool for mapping forest areas as they are cheap and easy to transport, and they provide high spatial resolution imagery of remote areas. We developed an object-based classification workflow for RGB UAV imagery which aims to identify and delineate palm tree crowns in the tropical rainforest by combining image processing and GIS functionalities using color and textural information in an integrative way to show one of the potential uses of UAVs in tropical forests. Ten permanent forest plots with 1170 reference palm trees were assessed from October to December 2017. The results indicate that palm tree crowns could be clearly identified and, in some cases, quantified following the workflow. The best results were obtained using the random forest classifier with an 85% overall accuracy and 0.82 kappa index.</p

STRESS-STRAIN RELATIONSHIP OF SOILS UNDER THREE DIFFERENT PRINCIPAL STRESSES

相異なる3主応力下の土の一般的な応力～ひずみ関係式を, 微視的観点からも妥当な土の根源的なパラメーターによって規定することは, 現在の土質力学の最重要課題の1つであると考えられる。ここでは, せん断時の土粒子の挙動についての微視的な解析から得たモービライズ面((τ/σn)max の面)上の応力～ひずみ間の基本関係式1》にもとづき, 複合モービライズ面の概念を新たに導入して, 相異なる3主応力下の土の一般的な応力～ひずみ関係式を誘導する。ついで, この応力～ひずみ関係式を三軸圧縮試験(最大主応力σ1≧中間主応力σ2=最小主応力σ3), 三軸伸張試験(σ1=σ2≧σ3), 平面ひずみ試験(中間主ひずみε2=0)および多軸試験(σ1≧σ2≧σ3, ε2≠0)の実測データによって検証し, その一般性を検討する。また非誘水せん断試験に適用する方法を述べ, その結果を実測データと比較する。さらに, この提案式によれば, 上記の試験法, 試料の間げき比, 拘束応力の大小にかかわらず, また砂であっても粘土であっても, 全て同一原理にもとづいて説明できることを示す。最後に, これらの応力～ひずみ関係式中の係数(λ, μ, μ', γ0)の物理的意味およびその決定法について述べる。Based on the basic relations between stress and strain on the mobilized ((τ/σN)max-) planewhich are obtained from a microscopic analysis of shear resistance and dilatancy, a general stress-strain relationship of soils under three different principal stresses is derived by introducing a newconcept of three mobilized planes. These stress-strain relationships are verified on the basis ofmeasured data obtained by the conventional triaxial compression test (σ1≧σ2=σ3), conventionaltriaxial extension test (σ1=σ2≧σ3), plane strain test (ε =0) and universal triaxial test (σ1≧σ2≧σ3, ε2≠0).相異なる3主応力下の土の一般的な応力～ひずみ関係式を,微視的観点からも妥当な土の根源的なパラメーターによって規定することは,現在の土質力学の最重要課題の1つであると考えられる。ここでは,せん断時の土粒子の挙動についての微視的な解析から得たモービライズ面((τ/σn)max の面)上の応力～ひずみ間の基本関係式1》にもとづき,複合モービライズ面の概念を新たに導入して,相異なる3主応力下の土の一般的な応力～ひずみ関係式を誘導する。ついで,この応力～ひずみ関係式を三軸圧縮試験(最大主応力σ1≧中間主応力σ2=最小主応力σ3),三軸伸張試験(σ1=σ2≧σ3),平面ひずみ試験(中間主ひずみε2=0)および多軸試験(σ1≧σ2≧σ3,ε2≠0)の実測データによって検証し,その一般性を検討する。また非誘水せん断試験に適用する方法を述べ,その結果を実測データと比較する。さらに,この提案式によれば,上記の試験法,試料の間げき比,拘束応力の大小にかかわらず,また砂であっても粘土であっても,全て同一原理にもとづいて説明できることを示す。最後に,これらの応力～ひずみ関係式中の係数(λ,μ,μ',γ0)の物理的意味およびその決定法について述べる。Based on the basic relations between stress and strain on the mobilized ((τ/σN)max-) planewhich are obtained from a microscopic analysis of shear resistance and dilatancy, a general stress-strain relationship of soils under three different principal stresses is derived by introducing a newconcept of three mobilized planes. These stress-strain relationships are verified on the basis ofmeasured data obtained by the conventional triaxial compression test (σ1≧σ2=σ3), conventionaltriaxial extension test (σ1=σ2≧σ3), plane strain test (ε =0) and universal triaxial test (σ1≧σ2≧σ3,ε2≠0)