An Assessment of Urban Vegetation Abundance in Accra Metropolitan Area, Ghana: A Geospatial Approach

Abstract

The essential role played by urban vegetation in making urban areas livable is often overlooked in many developing cities. This is the case of Ghana where its capital, Accra is developing at the expense of urban vegetation. This study was conducted at the metropolitan area of Accra to estimate how the extent of vegetation cover has changed in the period of 1986-2013, using remote sensing satellite data from Landsat TM and ETM+. Furthermore, views of key informants were assessed on changes in the livability of the city of Accra which may be attributed to loss of urban green vegetation in the city. It was found that between 1986 and 2013, 42.53 km2 of vegetation was lost representing 64.6% of total vegetation in 1986. The rate of change in vegetation cover between 1986 and 1991 measured around 2.14% of the total land area annually. This however, reduced in the subsequent years measuring 0.26% between 2002 and 2008. Key informants interviewed, also believe that the loss of vegetation in the city creates livability concerns relating to ecosystem functioning, temperature rise and air quality. It is therefore recommended for urban planners and decision makers to address three critical concerns of resilience, sustainability and livability, which are the missing links in the city development agenda.

Tracking Urban Expansion Using Random Forests for the Classification of Landsat Imagery (1986–2015) and Predicting Urban/Built-Up Areas for 2025: A Study of the Kumasi Metropolis, Ghana

“…The kappa statistics, user and producer accuracies also produced satisfactory results in our research. The accuracies were higher compared to accuracies produced in the works of [20,[37][38][39] for Kumasi and other parts of Ghana. The higher accuracy results obtained in this research could be attributed to the use of the machine learning algorithm, RF classifier.…”

“…Initial work on Kumasi and other cities in Ghana including [20,31,[33][34][35][36][37][38] utilized traditional classifiers for the classification of satellite imageries used in their researches. Hence, it is imperative to improve on the extant literature from the methodological point of view by utilizing the state of the art machine learning Random Forest (RF) classifier to classify satellite images of Kumasi.…”

Analysis of Pattern and Extent of Deforestation in Akure Forest Reserve, Ondo State, Nigeria

“…Akure forest reserve is geographically located in a humid rainforest zone of Akure South Local government area of Ondo State, Nigeria (Fig. 2) Owusu (2018) affirmed that the loss of vegetation in the city creates livability concerns relating to ecosystem functioning, temperature rise and air quality. He therefore recommended that decision makers should address three critical concerns of resilience, sustainability and livability.…”

Tree Cover of Accra’s Neighbourhoods—a Green Divide

“…In 1986, about 38% of the city was covered in vegetation, reducing to 13.5% in 2013. While neighbourhoods like Cantonments or Ridge lost some of their green cover, the majority of loss occurred in the northern part of the metropolis (Owusu 2018). Stow et al (2013) also report a decrease of almost 6% between 2002 and 2010 which they attribute to an increase in built-up areas as previously green areas are converted into residential and commercial land use.…”

“…While the city of Accra had continuously been expanding over time, increasing by 318% between 1975 and 1997, the majority of this expansion happened in the post-SAP years. This growth took the form of 'encroaching on rural settlements or into green spaces between rural settlements' (Yeboah 2000, p. 70) and it coincided with the period of highest amount of vegetation loss in Accra (Owusu 2018). Increased urbanisation and the conversion of green spaces into residential and commercial land use were, according to Owusu (2018), directly related to the SAP and its predecessor, the economic recovery programme.…”