Mapping Tropical Forest Biomass by Combining ALOS-2, Landsat 8, and Field Plots Data

Luong Viet Nguyen,Dinh Ho Tong Minh,Ryutaro Tateishi,Hoan Thanh Nguyen,Akihiko Kondoh,Tu Trong To,Ram Sharma

doi:10.3390/land5040031

Abstract

This research was carried out in a dense tropical forest region with the objective of improving the biomass estimates by a combination of ALOS-2 SAR, Landsat 8 optical, and field plots data. Using forest inventory based biomass data, the performance of different parameters from the two sensors was evaluated. The regression analysis with the biomass data showed that the backscatter from forest object (σ°forest) obtained from the SAR data was more sensitive to the biomass than HV polarization, SAR textures, and maximum NDVI parameters. However, the combination of the maximum NDVI from optical data, SAR textures from HV polarization, and σ°forest improved estimates of the biomass. The best model derived by the combination of multiple parameters from ALOS-2 SAR and Landsat 8 data was validated with inventory data. Then, the best validated model was used to produce an up-to-date biomass map for 2015 in Yok Don National Park, which is an important conservation area in Vietnam. The validation results showed that 74% of the variation of in biomass could be explained by our model.

Highlights

The role of forests in mitigating global climate change was again recognized in the ParisAgreement, with “key components of landmark climate deal agreed as well as an instrument to contribute to reducing emissions and enhancing carbon sinks” (COP 21, 2015)
Information on forest biomass is essential for increasing our understanding of the terrestrial carbon cycle and promoting conservation and sustainable management of the forest resources
−1 the variability (R = 0.64 and root mean square error (RMSE) = 48.04 Mg ha ) in the biomass could be explained by the best single parameter, σ°forest

Summary

Introduction

The role of forests in mitigating global climate change was again recognized in the Paris. With “key components of landmark climate deal agreed as well as an instrument to contribute to reducing emissions and enhancing carbon sinks” (COP 21, 2015). FAO report on global forest resource assessment, forest area reduced by 3% from 4128 M ha (1990) to. The rate of forest loss is higher in the tropics, whereas the temperate forest area has increased. The forest loss is higher in low income countries [2], and deforestation is a serious issue in many places in the world [3]. Information on forest biomass is essential for increasing our understanding of the terrestrial carbon cycle and promoting conservation and sustainable management of the forest resources. Remote sensing has become a major source of data to estimate biomass, carbon storage, and CO2 sequestration [4,5,6]

Objectives

Results

Conclusion