Toward a forest biomass reference measurement system for remote sensing applications

• Published in: Global change biology Vol. 29; no. 3; pp. 827 - 840
• Main Authors: Labrière, Nicolas, Davies, Stuart J., Disney, Mathias I., Duncanson, Laura I., Herold, Martin, Lewis, Simon L., Phillips, Oliver L., Quegan, Shaun, Saatchi, Sassan S., Schepaschenko, Dmitry G., Scipal, Klaus, Sist, Plinio, Chave, Jérôme
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.02.2023; Wiley; John Wiley and Sons Inc
• Subjects: aboveground biomass; Biomass; Carbon; Carbon capture and storage; Carbon sequestration; Climate change; Climate change mitigation; Earth Observation; Environmental conditions; Environmental Sciences; Forest biomass; forest vegetation; Forests; Literature reviews; Measurement; Mitigation; permanent plots; Remote sensing; Remote Sensing Technology; representativeness; Trees; Tropical Climate; Uptake; validation; Working conditions; Earth Observation; carbon; representativeness; aboveground biomass; forest vegetation; permanent plots; validation
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/gcb.16497

Forests contribute to climate change mitigation through carbon storage and uptake, but the extent to which this carbon pool varies in space and time is still poorly known. Several Earth Observation missions have been specifically designed to address this issue, for example, NASA's GEDI, NASA‐ISRO's NISAR and ESA's BIOMASS. Yet, all these missions' products require independent and consistent validation. A permanent, global, in situ, site‐based forest biomass reference measurement system relying on ground data of the highest possible quality is therefore needed. Here, we have assembled a list of almost 200 high‐quality sites through an in‐depth review of the literature and expert knowledge. In this study, we explore how representative these sites are in terms of their coverage of environmental conditions, geographical space and biomass‐related forest structure, compared to those experienced by forests worldwide. This work also aims at identifying which sites are the most representative, and where to invest to improve the representativeness of the proposed system. We show that the environmental coverage of the system does not seem to improve after at least the 175 most representative sites are included, but geographical and structural coverages continue to improve as more sites are added. We highlight the areas of poor environmental, geographical, or structural coverage, including, but not limited to, Canada, the western half of the USA, Mexico, Patagonia, Angola, Zambia, eastern Russia, and tropical and subtropical highlands (e.g. in Colombia, the Himalayas, Borneo, Papua). For the proposed system to succeed, we stress that (1) data must be collected and processed applying the same standards across all countries and continents; (2) system establishment and management must be inclusive and equitable, with careful consideration of working conditions; and (3) training and site partner involvement in downstream activities should be mandatory. A permanent, global, in situ, site‐based forest biomass reference measurement system relying on ground data of the highest possible quality is needed to validate products from biomass‐related Earth Observation missions. Here, we have assembled a list of almost 200 high‐quality sites. We explore how representative these sites are in terms of their coverage of environmental conditions, geographical space and biomass‐related forest structure, compared to those experienced by forests worldwide.