A comprehensive framework for assessing the accuracy and uncertainty of global above-ground biomass maps

Over the past decade, several global maps of above-ground biomass (AGB) have been produced, but they exhibit significant differences that reduce their value for climate and carbon cycle modelling, and also for national estimates of forest carbon stocks and their changes. This paper develops and demonstrates a framework to compare AGB maps with AGB estimates from a global collection of National Forest Inventories and research plots that accounts for the uncertainties of significant plot errors. Plot uncertainty estimates are used to assess four AGB maps. Maps are corrected for bias, and estimates of map precision are improved after spatial averaging as indicated by variograms. Total pantropical AGB and its associated standard deviation (SD) are then derived for the four map epochs. Plot uncertainty depends strongly on plot size, and is dominated by the combined errors from tree measurements and allometric models. Estimates of sampling errors are also important, especially in the most common case where plots are smaller than map pixels. The bias model is particularly sensitive to the map estimate of AGB and tree cover, and exhibits strong regional biases. AGB map errors have map-specific spatial correlation up to a range of 50-104 km. The derived pantropical forest AGB becomes increasingly close to that estimated by the Forest Resources Assessment and shows a similar decrease with time. The framework is applicable to both local and global-scale analysis.

ARAZA Arnan;  DE BRUIN Sytze;  HEROLD Martin;  QUEGAN S.;  LABRIERE Nicolas;  RODRIGUEZ VEGA Pedro;  AVITABILE Valerio;  SANTORO Maurizio;  MITCHARD E. T. A.;  RYAN Casey;  PHILLIPS Oliver L.;  WILLCOCK Simon;  VERBEEK Hans;  CARREIRAS Joao;  HEIN Lars;  SCHELHAAS M. J.;  PACHECO PASCAGAZA Ana Maria;  DA CONCEIÇÃO BISPO Polyanna;  VAGLIO LAURIN Gaia;  VIEILLEDENT Ghislain;  SLIK Ferry;  WIJAYA Arief;  LEWIS Simon L.;  MOREL Alexandra;  LIANG Jingjing;  SUKHDEO Hansrajie;  SCHEPASCHENKO Dmitry;  CAVLOVIC Jura;  GILANI Hammad;  LUCAS Richard; 

2022-02-25

ELSEVIER SCIENCE INC

JRC128376

0034-4257 (online),   

https://www.sciencedirect.com/science/article/pii/S0034425722000311,    https://publications.jrc.ec.europa.eu/repository/handle/JRC128376,   

10.1016/j.rse.2022.112917 (online),