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Landscapes and Landforms of Nigeria
GeoJournal, 2020
Land-use and cover change reflects choices in natural resource governance. Despite heavy targets ... more Land-use and cover change reflects choices in natural resource governance. Despite heavy targets on the forest and woodland, the southwest Nigeria states have little quantitative information on the magnitude and direction of land-use change across the states. This drives unsustainable land management and deforestation. This study utilized vegetation sampling and enumeration, GIS mapping and analyses of base maps and multi-temporal Landsat imageries to generate current vegetation status and time-series land-use and cover change for the southwest Nigeria. The results suggest that the woody species density in the forest plots ranges from 512 to 1040/ha with mean density of about 770.67/ha and species diversity values range from 2.014 to 2.911. The woody species in the savanna woodland ranged from 624 to 1232/ha in density and species diversity varies between 1.189 and 2.737. Relatively fewer number of trees of larger diameter at breast height in forest and low number of species per family in savanna reflect the influence of selective forest logging and woodland degradation. The study area experienced a historical net deforestation rate of − 1.1% per annum between 1986 and 2016 with deforestation rate of the primary forest at − 3.3% between 1986 and 2016 and − 10% between 2006 and 2016. Savanna woodland grew 0.8% annually from 1986 to 2016. The states recorded net deforestation rate ranging from − 2.63 to − 7.41% between 2006 and 2016. Reforestation through exotic Teak and Gmelina plantation grew at 43% annually between 1986 and 2016.
Tamarabrakemi Akoso, 2019
Wetlands are transition zones where the flow of water interacts with land and performs environmen... more Wetlands are transition zones where the flow of water interacts with land and performs environmental functions to create a balance in the ecosystem. Despite these functions, they are considered the be lost at an alarming rate. This study evaluates the fusion of Sentinel-1 (optical) variables and Sentinel-2 (synthetic aperture radar, SAR) for estimating the carbon pool in the coastal region of Southwest Nigeria. The field survey encompassed the collection of tree samples, top-soil samples (0-15m), plant litters, and plant herbs within a 25 × 25 m plot. Djomo’s allometric equation and the IPCC biomass-carbon constants were used to calculate the carbon stock from the sampled plot. The relationship between the field sampled carbon and the Sentinel variables produces 3 models to estimate the carbon of the study area. The first and second model observed field carbon within the sample plot correlated with Sentinel-1 and Sentinel-2 derived variables with R2= 0.342 and R2=0.708, respectively. But with the combined multi-source data of Sentinel-1 and Sentinel-2 using their complementary variables, the third model correlated with the field sampled carbon increased R2= 0.744. The result suggests that the spatially explicit model of the carbon pool was better estimated using the fusion of radar and optical satellite data from the Sentinel-1 and Sentinel-2 missions, respectively. The study recommends the use of freely available optical and radar images for cost-effective and timely mapping and estimation of carbon stock across different land covers for carbon trades and policies development to further improve wetland and forest management.
This research explores the concept of image classification, particularly Supervised classificatio... more This research explores the concept of image classification, particularly Supervised classification. It expounds on the method to develop a training area and describes some classification algorithm. It also practicalize some algorithm using a particulr training area.
Landscapes and Landforms of Nigeria
GeoJournal, 2020
Land-use and cover change reflects choices in natural resource governance. Despite heavy targets ... more Land-use and cover change reflects choices in natural resource governance. Despite heavy targets on the forest and woodland, the southwest Nigeria states have little quantitative information on the magnitude and direction of land-use change across the states. This drives unsustainable land management and deforestation. This study utilized vegetation sampling and enumeration, GIS mapping and analyses of base maps and multi-temporal Landsat imageries to generate current vegetation status and time-series land-use and cover change for the southwest Nigeria. The results suggest that the woody species density in the forest plots ranges from 512 to 1040/ha with mean density of about 770.67/ha and species diversity values range from 2.014 to 2.911. The woody species in the savanna woodland ranged from 624 to 1232/ha in density and species diversity varies between 1.189 and 2.737. Relatively fewer number of trees of larger diameter at breast height in forest and low number of species per family in savanna reflect the influence of selective forest logging and woodland degradation. The study area experienced a historical net deforestation rate of − 1.1% per annum between 1986 and 2016 with deforestation rate of the primary forest at − 3.3% between 1986 and 2016 and − 10% between 2006 and 2016. Savanna woodland grew 0.8% annually from 1986 to 2016. The states recorded net deforestation rate ranging from − 2.63 to − 7.41% between 2006 and 2016. Reforestation through exotic Teak and Gmelina plantation grew at 43% annually between 1986 and 2016.
Tamarabrakemi Akoso, 2019
Wetlands are transition zones where the flow of water interacts with land and performs environmen... more Wetlands are transition zones where the flow of water interacts with land and performs environmental functions to create a balance in the ecosystem. Despite these functions, they are considered the be lost at an alarming rate. This study evaluates the fusion of Sentinel-1 (optical) variables and Sentinel-2 (synthetic aperture radar, SAR) for estimating the carbon pool in the coastal region of Southwest Nigeria. The field survey encompassed the collection of tree samples, top-soil samples (0-15m), plant litters, and plant herbs within a 25 × 25 m plot. Djomo’s allometric equation and the IPCC biomass-carbon constants were used to calculate the carbon stock from the sampled plot. The relationship between the field sampled carbon and the Sentinel variables produces 3 models to estimate the carbon of the study area. The first and second model observed field carbon within the sample plot correlated with Sentinel-1 and Sentinel-2 derived variables with R2= 0.342 and R2=0.708, respectively. But with the combined multi-source data of Sentinel-1 and Sentinel-2 using their complementary variables, the third model correlated with the field sampled carbon increased R2= 0.744. The result suggests that the spatially explicit model of the carbon pool was better estimated using the fusion of radar and optical satellite data from the Sentinel-1 and Sentinel-2 missions, respectively. The study recommends the use of freely available optical and radar images for cost-effective and timely mapping and estimation of carbon stock across different land covers for carbon trades and policies development to further improve wetland and forest management.
This research explores the concept of image classification, particularly Supervised classificatio... more This research explores the concept of image classification, particularly Supervised classification. It expounds on the method to develop a training area and describes some classification algorithm. It also practicalize some algorithm using a particulr training area.