Forests for People

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Development study of the forest carbon

monitoring system using remote sensing

Yoshiki Yamagata, Hasi Bagan, Akihiko Ito and Minaco Adachi,

National Institute for Environmental Studies, Center for Global Environmental Research, Japan

educing emissions from deforestation and forest degrada-

tion (REDD) is considered to be one of the most important

carbon emission reduction efforts. The post-Kyoto regime

under the United Nations Framework Convention on Climate

Change requires forest carbon monitoring systems of signa-

tory nations. Deforestation and land-use changes are human

activities with a major impact on regional carbon budgets. For

instance, carbon emission from land-use change accounts for

between 12 per cent

and 20 per cent

of the total anthropo-

genic emissions worldwide. Forest carbon biomass in Southeast

Asia is the largest in the region; however, the area of primary

forest has continuously decreased due to land-use conversion.

The Food and Agriculture Organization (FAO) reported in 2010

that the forest area in South and Southeast Asia decreased by

0.68 million ha (23 per cent of the forest area) between 2000

and 2010.

In an effort to develop a larger-scale system for monitor-

ing forest carbon, we used time-series satellite (optical

and radar) remote-sensing data to track the history of

forest disturbance, and estimated the resulting forest

carbon budget using a terrestrial ecosystem model. We

found that the active radar sensor Phased-Array L-Band

Synthetic Aperture Radar (PALSAR) is especially advanta-

geous for monitoring tropical forest cover under clouds,

and that the time series of forest changes could be detected

using Moderate Resolution Imaging Spectroradiometer

(MODIS) data. We used a process-based model,

Vegetation Integrative Simulator for Trace Gases (VISIT),

to estimate the resulting forest carbon budget during the

last 25 years. Borneo Island is one of the main sites of

forest carbon tracking by the Global Earth Observation

System of Systems (GEOSS), because forest disturbances

Location of the study area

The left-hand image shows the location of the study area on Borneo Island. The right-hand image is the full-scene PALSAR image acquired on 25 March 2010

(RGB = HH, HV, and VV)