António Ferraz

António Ferraz
California Institute of Technology | CIT · Jet Propulsion Laboratory

28.39
 · 
PhD

About

62
Publications
21,947
Reads
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731
Citations
Research Experience
May 2014 - May 2016
Institut national de l’information géographique et forestière
Position
  • PostDoc Position
October 2007 - December 2011
Institut de Physique du Globe de Paris
Position
  • PhD Student

Publications

Publications (62)
Article
Selective logging, fragmentation, and understory fires directly degrade forest structure and composition. However, studies addressing the effects of forest degradation on carbon, water, and energy cycles are scarce. Here, we integrate field observations and high‐resolution remote sensing from airborne lidar to provide realistic initial conditions t...
Article
Full-text available
Plant biodiversity supports life on Earth and provides a range of important ecosystem services, but is under severe pressure by global change. Structural diversity plays a crucial role for carbon, water and energy cycles and animal habitats. However, it is very difficult to map and monitor over large areas, limiting our ability to assess the status...
Article
Full-text available
In tropical rainforests, trees size and number density are influenced by disturbance history, soil, topography, climate, and biological factors that are difficult to predict without detailed and widespread forest inventory data. Here, we quantify tree size–frequency distributions over an old‐growth wet tropical forest at the La Selva Biological Sta...
Article
Full-text available
Large trees, here defined as ≥60 cm trunk diameter, are the most massive organisms in tropical rain forest, and are important in forest structure, dynamics and carbon cycling. The status of large trees in tropical forest is unclear, with both increasing and decreasing trends reported. We sampled across an old-growth tropical rain forest landscape a...
Article
Full-text available
Surface Biology and Geology, a new NASA Earth observation effort, is developing a path forward for monitoring the Earth system from space. Citation: Schneider, F. D., A. Ferraz, and D. Schimel (2019), Watching Earth’s interconnected systems at work, Eos, 100, https://doi.org/10.1029/2019EO136205. Published on 31 October 2019.
Article
Full-text available
Global ecology – the study of the interactions among the Earth's ecosystems, land, atmosphere, and oceans – depends crucially on global observations: this paper focuses on space‐based observations of global terrestrial ecosystems. Early global ecology relied on extrapolation of detailed site‐level observations, using models of increasing complexity...
Article
Full-text available
Tropical forest canopies are comprised of tree crowns of multiple species varying in shape and height, and ground inventories do not usually reliably describe their structure. Airborne laser scanning data can be used to characterize these individual crowns, but analytical tools developed for boreal or temperate forests may require to be adjusted be...
Article
Full-text available
Background Wet tropical forests of Chocó, along the Pacific Coast of Colombia, are known for their high plant diversity and endemic species. With increasing pressure of degradation and deforestation, these forests have been prioritized for conservation and carbon offset through Reducing Emissions from Deforestation and forest Degradation (REDD+) me...
Article
Full-text available
We present an exploratory study examining the use of airborne remote-sensing observations to detect ecological responses to elevated CO2 emissions from active volcanic systems. To evaluate these ecosystem responses, existing spectroscopic, thermal, and lidar data acquired over forest ecosystems on Mammoth Mountain volcano, California, were exploite...
Article
Full-text available
Aim Large tropical trees form the interface between ground and airborne observations, offering a unique opportunity to capture forest properties remotely and to investigate their variations on broad scales. However, despite rapid development of metrics to characterize the forest canopy from remotely sensed data, a gap remains between aerial and fie...
Article
Aim: Large tropical trees form the interface between ground and airborne observations, offering a unique opportunity to capture forest properties remotely and to investigate their variations on broad scales. However, despite rapid development of metrics to characterize the forest canopy from remotely sensed data, a gap remains between aerial and fi...
Article
Full-text available
The forests of Kalimantan are under severe pressure from extensive land use activities dominated by logging, palm oil plantations, and peatland fires. To implement the forest moratorium for mitigating greenhouse gas emissions, Indonesia's government requires information on the carbon stored in forests, including intact, degraded, secondary, and pea...
Article
Tropical forests are a key component of the global carbon cycle. Yet, there are still high uncertainties in forest carbon stock and flux estimates, notably because of their spatial and temporal variability across the tropics. Several upcoming spaceborne missions have been designed to address this gap. High-quality ground data are essential for accu...
Article
Full-text available
Aim: Large tropical trees form the interface between ground and airborne observations, offering a unique opportunity to capture forest properties remotely and to investigate their variations on broad scales. However, despite rapid development of metrics to characterize the forest canopy from remotely sensed data, a gap remains between aerial and fi...
Article
Full-text available
Large tropical trees store significant amounts of carbon in woody components and their distribution plays an important role in forest carbon stocks and dynamics. Here, we explore the properties of a new lidar-derived index, the large tree canopy area (LCA) defined as the area occupied by canopy above a reference height. We hypothesize that this sim...
Article
Full-text available
NASA's Global Ecosystem Dynamic Investigation (GEDI) mission has been designed to measure forest structure using lidar waveforms to sample the earth's vegetation while in orbit aboard the International Space Station. In this paper, we used airborne large-footprint (LF) lidar measurements to simulate GEDI observations from which we retrieved ground...
Article
Full-text available
We present an exploratory study examining the use of airborne remote sensing observations to detect ecological responses to elevated CO2 emissions from active volcanic systems. To evaluate these ecosystem responses, existing spectroscopic, thermal, and lidar data acquired over forest ecosystems on Mammoth Mountain volcano, California, were exploite...
Article
Full-text available
Mountain ecosystems are among the most fragile environments on Earth. The availability of timely updated information on forest 3D structure would improve our understanding of the dynamic and impact of recent disturbance and regeneration events including fire, insect damage, and drought. Airborne lidar is a critical tool for monitoring forest change...
Article
Full-text available
Large tropical trees store significant amounts of carbon in woody components and their distribution plays an important role in forest carbon stocks and dynamics. Here, we explore the properties of a new Lidar derived index, large tree canopy area (LCA) defined as the area occupied by canopy above a reference height. We hypothesize that this simple...
Article
Full-text available
Background Accurate estimation of aboveground forest biomass (AGB) and its dynamics is of paramount importance in understanding the role of forest in the carbon cycle and the effective implementation of climate change mitigation policies. LiDAR is currently the most accurate technology for AGB estimation. LiDAR metrics can be derived from the 3D po...
Article
Full-text available
National forest inventories in tropical regions are sparse and have large uncertainty in capturing the physiographical variations of forest carbon across landscapes. Here, we produce for the first time the spatial patterns of carbon stored in forests of Democratic Republic of Congo (DRC) by using airborne LiDAR inventory of more than 432,000 ha of...
Article
Full-text available
Airborne lidar is a technology well-suited for mapping many forest attributes, including aboveground biomass (AGB) stocks and changes in selective logging in tropical forests. However, trade-offs still exist between lidar pulse density and accuracy of AGB estimates. We assessed the impacts of lidar pulse density on the estimation of AGB stocks and...
Article
Full-text available
Improvements in the management of pine plantations result in multiple industrial and environmental benefits. Remote sensing techniques can dramatically increase the efficiency of plantation management by reducing or replacing time-consuming field sampling. We tested the utility and accuracy of combining field and airborne lidar data with Random For...
Technical Report
Full-text available
High Resolution Carbon Distribution in Forests of Democratic Republic of Congo A summary report of the Carbon Map and Model Project Performed at the University of California Los Angeles
Conference Paper
Full-text available
Tropical forests are an important component of global carbon stocks, but the response of tropical forest biomass to climate is not sufficiently studied or understood. Airborne lidar (Light Detection and Ranging) is well suited for quantifying tropical forest carbon stocks, however, trade-offs exist between lidar pulse density and acquisition cost....
Conference Paper
Full-text available
Tropical forest play an important role in mitigating global warming. Airborne LiDAR (Light Detection and Ranging) has been used to predict aboveground biomass in tropical forest. However, few studies have modeling and predicting tropical forest AGB at plot-level from individual tree LiDAR-derived metrics. The aim of this study was to model and pred...
Conference Paper
Full-text available
Airborne lidar has become a well-suited technology for predicting and mapping many tropical forest attributes, including aboveground biomass (AGB). However, trade-offs exist between lidar pulse density and acquisition cost. The aim of this study was to evaluate the influence of lidar pulse density on AGB change predictions using airborne lidar and...
Article
Full-text available
Characterization of tropical forest trees has been limited to field-based techniques focused on measurement of diameter of the cylindrical part of the bole, with large uncertainty in measuring large trees with irregular shapes, and other size attributes such as total tree height and the crown size. Here, we introduce a methodology to decompose lida...
Article
Full-text available
The scientific community involved in the UN-REDD program is still reporting large uncertainties about the amount and spatial variability of CO 2 stored in forests. The main limitation has been the lack of field samplings over space and time needed to calibrate and convert remote sensing measurements into aboveground biomass (AGB). As an alternative...
Article
Full-text available
Canopy structure plays an essential role in biophysical activities in forest environments. However, quantitative descriptions of a 3-D canopy structure are extremely difficult because of the complexity and heterogeneity of forest systems. Airborne laser scanning (ALS) provides an opportunity to automatically measure a 3-D canopy structure in large...
Article
Full-text available
In forested mountainous areas, the road location and characterization are invaluable inputs for various purposes such as forest management, wood harvesting industry, wildfire protection and fighting. Airborne topographic lidar has become an established technique to characterize the Earth surface. Lidar provides 3D point clouds allowing for fine rec...
Article
Full-text available
The canopy density model (CDM), a new product interpolated from airborne laser scanner (ALS) data and dedicated to forest structure characterization is presented. It exploits both the multiecho capability of the ALS and a nonparametric density estimation technique called kernel density estimators (KDEs). The CDM is used to delineate the outmost per...
Article
Full-text available
In forested mountaneous areas, the road location and its geometric description are necessary information for many purposes linked to ecological issues. Topographic airborne laser scanning has become an established technique to characterize the Earth surface. Lidar provides 3D point clouds allowing for a fine reconstruction of the topography : very...
Article
Full-text available
Timely and accurate measuremen ts of forest parameters are critical for ecosystem studies, sustainable forest resources management, monitoring and planning. This paper presents a processing chain for individual tree segmentation over large areas with airborne LiDAR 3D point cloud and very high resolution (VHR) optical imagery. The proposed processi...
Conference Paper
Full-text available
In this paper, we present an approach that is able to deal with large-scale road network extraction in montaneous forested areas. While former methods focus on delineating patches of roads without computing a coherent road network, we formu-late a very large number of road hypothesis that are pruned using a graph reasoning and weak a priori knowled...
Conference Paper
Full-text available
Timely and accurate measurements of forest parameters are critical for ecosystem studies, sustainable forest resources management, monitoring and planning. This paper presents a processing chain for individual tree segmentation over large areas with airborne LiDAR 3D point cloud and very high resolution (VHR) optical imagery. The proposed processin...
Article
Full-text available
Dans le cadre des politiques de lutte contre le réchauffement climatique (programme UN-REDD des Nations Unies), les techniques de télédétection sont désormais utilisées pour extrapoler des estimations de la biomasse aérienne à l’échelle locale (dérivées à partir des mesures terrain obtenues via des inventaires forestiers) sur des grandes surfaces o...
Article
Full-text available
Accurate Digital Terrain Models (DTMs) are inevitable inputs for mapping and analyzing areas subject to natural hazards. Topographic airborne laser scanning has become an established technique to characterize the Earth's surface: lidar provides 3D point clouds allowing for a fine reconstruction of the topography while preserving high frequencies of...
Conference Paper
Full-text available
Accurate Digital Terrain Models (DTM) are inevitable inputs for mapping areas subject to natural hazards. Topographic lidar scan-ning has become an established technique to characterize the Earth surface: and reconstruct the topography. For flood hazard model-ing in coastal areas, the key step before terrain modeling is the dis-crimination of land...
Conference Paper
Full-text available
Canopy height and canopy cover are two important biophysical variables in forest characterization. As far as airborne laser scanning (ALS) studies is concerned, canopy height has been mapped at a high spatial resolution through canopy height models (CHM). Conversely, canopy cover had been computed at a coarser resolution (plot-level) by means of pe...
Conference Paper
Full-text available
Current methods for accurately estimating vegetation biomass with remote sensing data require extensive, representative and time consuming field measurements to calibrate the sensor signal. In addition, such techniques focus on the topmost vegetation canopy and thus they are of little use over multi-layered forest ecosystems where the underneath st...
Conference Paper
Full-text available
Consistent and accurate information on 3D forest canopy structure is required by many applications like forest inventory, management, logging, fuel mapping, habitat studies or biomass estimate. Compared to other remote sensing techniques (e.g., SAR or photogrammetry), airborne laser scanning is an adapted tool to provide such information by generat...
Article
Full-text available
Wildland fire is a common threat in many European countries, especially in the Mediterranean Basin. Every summer in Portugal, Spain, Greece, Italy or France thousands of hectares of forests and shrub-land burn and even people are endangered. Since wildland fires represent a social and economic risk for the society, there is a compelling interest in...
Technical Report
Full-text available
Wildland fire is a common threat in many European countries, especially in the Mediterranean Basin. Every summer in Portugal, Spain, Greece, Italy or France thousands of hectares of forests and shrub-land burn and even people are endangered. Since wildland fires represent a social and economic risk for the society, there is a compelling interest in...

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Project (1)
Project
Forest structure change over mountainous forests using ASO lidar data