Scholarly works in Social and Environmental Forestry
Permanent URI for this collectionhttps://repository.ui.edu.ng/handle/123456789/13518
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Item Temperature variability and impact of vegetation cover in Ibadan metropolis, Ibadan, Nigeria(Faculty of Agriculture, Usmanu Danfodiyo University, Sokoto, Nigeria, 2021) Nwatu, U. J.; Alo A. A.; Agbor, C. F.This study evaluates the changes in Urban Green Spaces (UGS) and the impact of such changes on surface temperature in Ibadan Metropolis between 1984 and 2018 using Landsat images. Digital numbers of the imageries were converted to physical quantities, radiance, and brightness temperature, while the temperature retrieval from thermal channels of Landsat imagery was carried out and the derived surface temperature validation was done through near-surface air temperature. This was followed by the reclassification of the images using Normalized Difference Vegetation Index (NDVI) as a proxy for vegetation cover and was regressed with urban temperature to observe their nexus, which explains the ability of UGS to absorb solar radiation in the study area. The land use land cover maps of the metropolis were developed from green, red and near-infrared channels of Landsat data in Idrisi software environment using maximum likelihood classifier. Results show that the mean temperature of Ibadan metropolis increased from 33.29℃ to 35.76℃ over 34 years, and the temperature of different land cover types considered in this study revealed that built-up and bare soil areas recorded the highest temperature changes compared to other land cover types (green spaces and water body). Also, the correlation analysis between UGS and ST showed a strong negative relationship with R2 values ranging from -0.71 to -0.89. The study, therefore, concludes that the relationship is strong enough to ascertain that urban vegetation cover has the capacity to mitigate climate change effects. The increase in temperature may contribute to the variations in surface temperature, thus giving rise to the urban heat island effect. The study revealed the efficiency of geospatial techniques in data capturing for reliable information on sustainable management of urban green spaces.Item Human Settlements Interactions and Deforestation in Gambari Forest Reserve located in Oluyole Local Government Area (LGA) of Oyo State, Nigeria(The University of Port Harcourt, 2021) Agbor, C. F.; Alo, A. A.; Aigbokhan, O.J .This study was designed to examine changes in land cover types and the interaction of human settlements with the forest and impact of such interaction on the reserve. Community leaders and randomly selected community dwellers in each of the selected settlements were sampled for group discussion to obtain information on population and services of the forest that attract them to the reserve. Landsat images of 1984 and 2019 were used to extract land cover types using maximum likelihood classifier in Idrisi environment. The level of attractiveness and Interactions of the communities with the reserve were determined employing gravitational model. Results show that there was an increase in the size and number of settlements within the study area and decrease in in forest cover by 34% and 6.02% respectively. It was also revealed from the study that about 39% of the total area was taken over by development (building, roads and other classes) within the forest reserve, while 3% of the developed area gave way to forest cover. The degraded parts of the reserve in recent time was about 16% of the total reserve area and about 78% remained forest cover. From the results it is obvious that the level of interaction and imparts of such interaction depends on the community’s population size rather than distance. It is therefore imperative to regulate the activities of adjoining communities and those within the Gambari forest reserve by appropriate authorities.Item Forest Cover Dynamics of a Lowland Rainforest in Southwestern Nigeria Using GIS and Remote Sensing Techniques(Scientific Research Publishing, 2021) Oluwajuwon1, T. V.; Alo A. A.; Ogana, F. N.; Adekugbe, O. A.The rate of forest degradation and deforestation in Nigeria has been increasing over the years and is prominent in the southwestern parts. Despite the significant change and degradation observed in a lowland rainforest in the region—Ogbese Forest Reserve, there is a great dearth of information about the level of forest cover change. Therefore, this study determined the cover dynamics of the rainforest reserve over the epoch of 20 years using Geographic Information System and remote sensing techniques. Coordinates of the boundary and some other benchmark places within the forest reserve were obtained. Secondary data collection included: Landsat imageries of 1998, 2002 and 2018. An interview guide was used to obtain information from forest officials and locals of the surrounding communities to complement the spatial data obtained. Image classification was done using the maximum likelihood algorithm. The rate of change across the epochs was determined using the area of the land cover classes. The level of vegetation disturbance in the reserve was determined through Normalized Difference Vegetation Index. Five different forest cover classes were identified in the study area: forest, plantation, farmland, grassland, and bare land. The natural forest reduced significantly from 34.43 km2 (48%) in 1998 to 8.73 km2 (12%) in 2002 and was depleted further by 2018, while other cover classes increased. NDVI value also reduced from 0.25 to 0.13. Agriculture, among others, was observed as the main driver of forest degradation and deforestation in Ogbese Forest Reserve. The study concluded that the remaining forest (i.e. plantation) could also be depleted by 2025, as it decreases by −0.94 km2 per year if proper reforestation and management practices are not introduced.Item Spatio-Temporal Dynamics of Urban Green Space and Temperature in Ado-Ekiti Metropolis, Nigeria(Forests and Forest Products Journal, 20, pp.40-53, 2020) Okikiola M. A.; Alo A. A.The Nexus between the Urban Green Space (UGS) and Land Surface Temperature (LST) helps to formulate policy for sustainable management of UGS where there is an urban sprawl like Ado Ekiti. However, there is a dearth of information on UGS and LST in Ado-Ekiti. Therefore, this study adopted remote sensing and geographic information system techniques to determine the dynamics and nexus between UGS and LST as well as investigating the perceived factors responsible for the UGS changes in Ado-Ekiti metropolis, Nigeria with a view to providing relevant information for sustainable management of the UGS and mitigating the Urban Heat Island. Landsat imageries of 1987 (TM), 1998 (ETM) and 2019 (OLI) were obtained. Map of Ado-Ekiti was georeferenced and digitized to obtain its shapefile. The maximum likelihood algorithm of supervised classification in ArcGIS was used to classify Landsat imageries. The shapefile was superimposed on the classified imageries and clipped for the determination of land use land cover sizes. The LST was extracted from the imageries by converting the digital numbers to the surface temperature. Correlation analysis was used to determine the nexus between the UGS and LST. Four land use land cover: green spaces, built-up area, water bodies and bare land, were identified in the Ado-Ekiti metropolis. The UGS decreased from 74.4% in 1987 to 38.7% in 2019. Similarly, water bodies reduced from 0.9% in 1987 to 0.1% in 2019 respectively. However, built-up area and bare land increased from 21.9% and 2.9% in 1987 to 51.1% and 10.5% in 2019 respectively. The LST in Ado-Ekiti metropolis increased from 22.1°C in 1987 to 30.5 °C in 2019 respectively. The Built-up area and bare land had the highest LST values compared with UGS and water body in all the years. The relationship between the UGS dynamics and LST was negatively correlated with r2 ranging from -0.51 to -0.83. By the year 2049, the vegetation would have reduced to 36.0% while built-up and bare land would have increased to 52.4%. on the other hand, water with no significant change.Item Modelling forest cover dynamics in Shasha forest reserve, Osun state, Nigeria(Faculty of Agriculture, Usmanu Danfodiyo, Sokoto, Nigeria, 2020) Alo A.A.; Adetola, A.A.; Agbor, C.F.Understanding the dynamics of forest cover change is vital to forest manager for planning, formulation of policies and decision making. Nigeria’s forest reserves have witnessed significant changes over the years due to various anthropogenic activities. Incessant activities of poachers, illegal fellers and other farming activities in Shasha Forest Reserve have adverse effects on the ecosystem with consequence for global warming. However, there is no up-to-date information on the dynamics of forest cover in Shasha Forest Reserve. Therefore, this study aimed at assessing forest cover changes using remote sensing in Shasha Forest Reserve. Landsat Thematic mapper (TM), Enhanced Thematic Mapper (ETM+) and Operational Land Imager (OLI) data for the periods of 1984, 2000 and 2017 were obtained. The Landsat images were pre-processed and classified using maximum likelihood classification algorithm. The Classification was based on Anderson scheme of land use/cover for change detection between 1984 and 2017. Kappa coefficient was used for accuracy assessment. The future pattern of forest cover changes for 2034 was forecast using the Multi-Layer Perception (MLP) Markov chain model in IDRISI. Three land cover classes were identified: Built up, Shrubs and Forest land. Built up and Shrubs increased at an annual rate of 0.09% and 0.18% respectively and forest decreased at an annual rate of 0.27% between 1984 and 2017. Large area of forest land has been converted to built-up and shrubs with no significant replacement from 2000 till date. The forest was projected to decrease between 2017 till 2034 at the rate of 0.15% per annum.Item Geospatial modeling of forest landscape assessment: a case study from Ikere forest reserve(African Journal of Open Libraries (AJOL)., 2020) Chukwuka A. F.; Alo A. A.; Aigbokhan, O. J.This study set out to assess the dynamic characteristics of the Ikere forest reserve landscape between 1985 and 2017 using remote sensing data and spatial metrics. Landscape of the study area maintained complex patterns of spatial heterogeneity over the years. Forest cover loss to other land cover types results in new large non-forest area at increasing rate. As at the year 2017, the changes in land cover types were not yet at equilibrium, thus the need to determine the future forest cover extent using a three-way markov Chain model. The decrease in number of patches of forest land (NumP) with increase in its mean patch size (MPS) shows that the forest is becoming a single unit probably due to clearing of existing patches of forest trees. The decrease in class diversity and evenness (SDI and SEI) of the general landscape over the years strengthens this assertion. The findings of this study would be very helpful to government and other stakeholders responsible for ensuring sustainable forest and general environment.