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News - Feb 8, 2021

REDD + in Madagascar: a brilliant thesis defense on Forest Cover Dynamics

Fety Rakotomalala admirably defended his PhD thesis on December 22, 2020 at the University of Antananarivo

Fety Rakotomalala received the title of Doctorate in Physics and Applications, Specialty: Physics of the Globe. His thesis is entitled: "Measurement and Monitoring of Forest Cover Dynamics: Case of the Eastern Madagascar Humid Forest Ecoregion".

Methodology and results

The thesis proposes innovative methodological elements combining the analysis of spatial remote sensing data and field data for the monitoring of deforestation, degradation and regeneration of forests in Madagascar. The proposed method involves the spatial analysis of the evolution of forest cover crossed with the evolution of carbon stocks in the aboveground biomass over the whole rainforests the ecoregion of Madagascar. The results of this thesis shed new light on little-studied forest dynamics (forest degradation and restoration) and tools necessary for the establishment of the national forest cover monitoring system within the framework of the REDD+ mechanism in Madagascar.


Research framework

The thesis has benn carried out in partnership with the Institute and Observatory of Geophysics of Antananarivo (IOGA) of the University of Antananarivo and the NGO Nitidæ. Fety was supervised by Professor Solofo Rakotoniaina and Dr. Clovis Grinand (Nitidæ).

The jury was composed of :
- Mrs. Georgette RAMANANTSIZEHENA (Professor, President of the Jury)
- M.Solofoarisoa RAKOTONIAINA (Professor, Thesis Director)
- M.Clovis GRINAND (Doctor, co-director of thesis)
- Mr. Solofo RAKOTONDRAOMPIANA, (Professor, internal rapporteur)
- Mrs. Miadana Harisoa FARAMALALA (Professor, external rapporteur)
- Mr. Lilian BLANC (Doctor, Examiner)
- Mr.Samuel RAZANAKA (Professor, Examiner)

The whole jury congratulated the candidate by underlining the quality and quantity of his scientific work as well as his pedagogical skills.


Abstract

The fine and large-scale quantification of the dynamics of the forest cover is essential in the management of natural resources, providing knowledge to fight against the loss of biodiversity and reducing greenhouse gas emissions. In Madagascar, several recent studies have shown the importance of deforestation, mainly linked to slash and burn agriculture. However, the national definition of forests has never been taken into account in their data processing. In addition, there is little or no information on the extent and importance of forest degradation and regeneration processes. Thus, the objective of this thesis is to quantify deforestation, degradation and forest regeneration in the humid forest ecoregion of eastern Madagascar between 2000 and 2015. An approach based on the detection of multi-dates images changes has been applied to estimate and analyze the level of deforestation. The estimation of degradation and regeneration was mainly carried out by simultaneously analyzing the evolution of the cover and the forest carbon stock. Deforestation was estimated at 90,171 ha/year between 2000 and 2005, 27,103 ha/year between 2005 and 2010, 33,978 ha/year between 2010 and 2013 and 80,626 ha/year between 2013 and 2015. The forest degradation was estimated at 20,327 ha/year and regeneration at 7,997 ha/year between 2000 and 2015. The validation of these results was carried out by visual inspection of the points on high spatial resolution images. The overall accuracy of the deforestation map has been estimated at 90% while for degradation and regeneration has been estimated at 88.5%. The present thesis thus proposes innovative methodological elements based on spatial remote sensing for monitoring the dynamics of forest cover in Madagascar. It also contributes to providing the statistical information necessary for the establishment of the national forest cover monitoring system.
Keywords: Deforestation, degradation, regeneration, aboveground biomass, remote sensing

>> The pdf version of the thesis is available on the website of the University of Antananarivo

>> The presentation of the thesis is available below