Using the U-net convolutional network to map forest types and disturbance in the Atlantic rainforest with very high resolution images

Author(s)

Wagner, Fabien H. ^[1] ; Sanchez, Alber ^[1] ; Tarabalka, Yuliya ^{[2, 3]} ; Lotte, Rodolfo G. ^[1] ; Ferreira, Matheus P. ^{[1, 4]} ; Aidar, Marcos P. M. ^[5] ; Gloor, Emanuel ^[6] ; Phillips, Oliver L. ^[6] ; Aragao, Luiz E. O. C. ^{[1, 7]}

Affiliation

^[1] Natl Inst Space Res INPE, Remote Sensing Div, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[2] INRIA Sophia Antipolis, F-06902 Sophia Antipolis - France

^[3] Luxcarta Technol, Parc Act Argile, Lot 119b, F-06370 Mouans Sartoux - France

^[4] Mil Inst Engn IME, Cartog Engn Sect, Praca Gen Tiburcio 80, BR-22290270 Rio De Janeiro, RJ - Brazil

^[5] Inst Bot, Dept Plant Physiol & Biochem, PB 4005, BR-01061970 Sao Paulo - Brazil

^[6] Univ Leeds, Sch Geog, Ecol & Global Change, Leeds LS2 9JT, W Yorkshire - England

^[7] Univ Exeter, Coll Life & Environm Sci, Exeter EX4 4RJ, Devon - England

• Document type: Journal article
• Source: REMOTE SENSING IN ECOLOGY AND CONSERVATION; v. 5, n. 4, p. 360-375, DEC 2019.
• Web of Science Citations: 17

Abstract

Mapping forest types and tree species at regional scales to provide information for ecologists and forest managers is a new challenge for the remote sensing community. Here, we assess the potential of a U-net convolutional network, a recent deep learning algorithm, to identify and segment (1) natural forests and eucalyptus plantations, and (2) an indicator of forest disturbance, the tree species Cecropia hololeuca, in very high resolution images (0.3 m) from the WorldView-3 satellite in the Brazilian Atlantic rainforest region. The networks for forest types and Cecropia trees were trained with 7611 and 1568 red-green-blue (RGB) images, respectively, and their dense labeled masks. Eighty per cent of the images were used for training and 20% for validation. The U-net network segmented forest types with an overall accuracy >95% and an intersection over union (IoU) of 0.96. For C. hololeuca, the overall accuracy was 97% and the IoU was 0.86. The predictions were produced over a 1600 km(2) region using WorldView-3 RGB bands pan-sharpened at 0.3 m. Natural and eucalyptus forests compose 79 and 21% of the region's total forest cover (82 250 ha). Cecropia crowns covered 1% of the natural forest canopy. An index to describe the level of disturbance of the natural forest fragments based on the spatial distribution of Cecropia trees was developed. Our work demonstrates how a deep learning algorithm can support applications such as vegetation, tree species distributions and disturbance mapping on a regional scale. (AU)

• FAPESP's process: 16/03397-7 - Tools for satellite images management in array databases
• Grantee: Alber Hamersson Sánchez Ipia
• Support Opportunities: Scholarships in Brazil - Technical Training Program - Technical Training
• FAPESP's process: 16/24977-1 - Measuring and mapping Atlantic Forest canopy foliar traits with hyperspectral images and radiative transfer modeling
• Grantee: Matheus Pinheiro Ferreira
• Support Opportunities: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 15/50484-0 - Functional diversity of intact and regenerating Amazon, Atlantic Forest, and Cerrado systems using hyperspectral imagery
• Grantee: Fabien Hubert Wagner
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 13/50533-5 - Understanding the response of photosynthetic metabolism in tropical forests to seasonal climate variations
• Grantee: Luiz Eduardo Oliveira e Cruz de Aragão
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/51872-5 - ECOFOR: Biodiversity and ecosystem functioning in degraded and recovering Amazonian and Atlantic Forests
• Grantee: Carlos Alfredo Joly
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants