Above ground woody biomass estimation in a communal African savanna woodland using microwave remote sensing based approach

Estimations of available fuelwood resources in communal savanna woodlands are widely based on conventional terrestrial and optical remote sensing approaches, which are constrained by limited geographic footprints and the use of leaf area indices and normalised difference vegetation indices, as surr...

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Main Authors: Paradzayi, Charles, Annegarn, H. J., Schmullius, C.
Format: Article
Language:English
Published: Midlands State University 2015
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Online Access:http://hdl.handle.net/11408/664
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author Paradzayi, Charles
Annegarn, H. J.
Schmullius, C.
author_facet Paradzayi, Charles
Annegarn, H. J.
Schmullius, C.
author_sort Paradzayi, Charles
collection DSpace
description Estimations of available fuelwood resources in communal savanna woodlands are widely based on conventional terrestrial and optical remote sensing approaches, which are constrained by limited geographic footprints and the use of leaf area indices and normalised difference vegetation indices, as surrogates for above ground biomass. As a result, reliable information about the location and estimated quantities of available woody biomass is scarce at local, national and global scales. Recent developments have shown that classification of backscatter information contained in full polarimetric radar retrievals from satellite borne sensors can discriminate between woody and non-woody vegetation. The intensity of the backscattered signal has been shown to be sensitive to above ground biomass density. However, no such studies have been reported across African savanna woodlands. This paper presents a study which used full polarimetric ALOS PALSAR retrievals to map and quantify fuelwood resources in communal savanna woodland in Welverdiend village, South Africa. Unsupervised entropy/alpha angle Wishart classification and maximum likelihood classification procedures are used to characterise the scattering classes from the ALOS PALSAR retrievals into eight major terrain scattering mechanisms. Five vegetation classes (random anisotropic, forest double bounce, vegetation, dihedral and dipole) are identified that are closely related to backscattering from woody vegetation components. Correlations between backscatter intensities acquired under dry and wet conditions with above-ground biomass densities estimated from field surveys are investigated to derive equations for predicting biomass densities. The regression analysis supports findings of similar studies where the HV backscatter intensity showed moderately strong relationship (R2>0.6) with above ground biomass densities. The inverted regression equations were used to estimate the biomass densities for areas covered with woody vegetation. Knowledge about the location and distribution of woody biomass has significant implications for fuelwood management and carbon sequestration initiatives. A combination of woodland management interventions, coupled with the transition to modern energy sources, has the potential of turning communal woodlands into carbon sinks.
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spelling ir-11408-6642022-06-27T13:49:06Z Above ground woody biomass estimation in a communal African savanna woodland using microwave remote sensing based approach Paradzayi, Charles Annegarn, H. J. Schmullius, C. Full polarimetric, synthetic aperture radar, above-ground woody biomass, fuelwood, ALOS PALSAR, savanna woodlands Estimations of available fuelwood resources in communal savanna woodlands are widely based on conventional terrestrial and optical remote sensing approaches, which are constrained by limited geographic footprints and the use of leaf area indices and normalised difference vegetation indices, as surrogates for above ground biomass. As a result, reliable information about the location and estimated quantities of available woody biomass is scarce at local, national and global scales. Recent developments have shown that classification of backscatter information contained in full polarimetric radar retrievals from satellite borne sensors can discriminate between woody and non-woody vegetation. The intensity of the backscattered signal has been shown to be sensitive to above ground biomass density. However, no such studies have been reported across African savanna woodlands. This paper presents a study which used full polarimetric ALOS PALSAR retrievals to map and quantify fuelwood resources in communal savanna woodland in Welverdiend village, South Africa. Unsupervised entropy/alpha angle Wishart classification and maximum likelihood classification procedures are used to characterise the scattering classes from the ALOS PALSAR retrievals into eight major terrain scattering mechanisms. Five vegetation classes (random anisotropic, forest double bounce, vegetation, dihedral and dipole) are identified that are closely related to backscattering from woody vegetation components. Correlations between backscatter intensities acquired under dry and wet conditions with above-ground biomass densities estimated from field surveys are investigated to derive equations for predicting biomass densities. The regression analysis supports findings of similar studies where the HV backscatter intensity showed moderately strong relationship (R2>0.6) with above ground biomass densities. The inverted regression equations were used to estimate the biomass densities for areas covered with woody vegetation. Knowledge about the location and distribution of woody biomass has significant implications for fuelwood management and carbon sequestration initiatives. A combination of woodland management interventions, coupled with the transition to modern energy sources, has the potential of turning communal woodlands into carbon sinks. 2015-09-14T13:00:02Z 2015-09-14T13:00:02Z 2013 Article http://hdl.handle.net/11408/664 en Midlands State University Journal of Science Agriculture and Technology;Vol. 4 (1); p. 4-25 open Midlands State University
spellingShingle Full polarimetric, synthetic aperture radar, above-ground woody biomass, fuelwood, ALOS PALSAR, savanna woodlands
Paradzayi, Charles
Annegarn, H. J.
Schmullius, C.
Above ground woody biomass estimation in a communal African savanna woodland using microwave remote sensing based approach
title Above ground woody biomass estimation in a communal African savanna woodland using microwave remote sensing based approach
title_full Above ground woody biomass estimation in a communal African savanna woodland using microwave remote sensing based approach
title_fullStr Above ground woody biomass estimation in a communal African savanna woodland using microwave remote sensing based approach
title_full_unstemmed Above ground woody biomass estimation in a communal African savanna woodland using microwave remote sensing based approach
title_short Above ground woody biomass estimation in a communal African savanna woodland using microwave remote sensing based approach
title_sort above ground woody biomass estimation in a communal african savanna woodland using microwave remote sensing based approach
topic Full polarimetric, synthetic aperture radar, above-ground woody biomass, fuelwood, ALOS PALSAR, savanna woodlands
url http://hdl.handle.net/11408/664
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AT annegarnhj abovegroundwoodybiomassestimationinacommunalafricansavannawoodlandusingmicrowaveremotesensingbasedapproach
AT schmulliusc abovegroundwoodybiomassestimationinacommunalafricansavannawoodlandusingmicrowaveremotesensingbasedapproach