A Survey of the Economically Valued Forest Trees and Shrubs at the Proposed Site for an Airport in Asaba, Delta State, Nigeria
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Journal of Horticulture and Forestry Vol. 2(8) pp.190-195, September 2010 Available online http://www.academicjournals.org/jhf ISSN 2006-9782 ©2010 Academic Journals Full Length Research Paper A survey of the economically valued forest trees and shrubs at the proposed site for an airport in Asaba, Delta State, Nigeria O. M. Agbogidi Department of Forestry and Wildlife, Faculty of Agriculture, Delta State University, Asaba Campus, Asaba, Delta State, Nigeria. E-mail: [email protected]. Tel: +2347038679939, +2348056306219. Accepted 19 October, 2009 This study assessed the economically valued forest trees and shrubs at the proposed site for an airport in Asaba, Delta State with a view to noting them before the commencement of work in the area. 2520 × 20 m quadrants were laid randomly along the five 1 km line transect and assessed accordingly. Thirty tree species producing various economically valued products were assessed and 10 out of the 33 were observed to be rare while 23 were abundant. Fifteen species of shrubs were assessed out of which, 8 were identified as abundant and rare (3). Products collected from these plants have varying use categories as leafy vegetables, edible and medicinal fruits, leaves, seeds, barks, fodder, poles, timber, stakes and chewing sticks. The study established that over exploitation, exploration and conversion of forest ecosystems in the area has brought about decimation of biodiversity as well as extinction of many valuable plant and animal species. It is strongly recommended that domestication of indigenous tree and shrub species should be encouraged and supported. Conservation efforts, through the establishment of nature reserves, botanical gardens, sacred grooves, sanctuaries, rare breed centers, game banks and on-site gene banks should be supported to enhance sustainability. Key words: Forest trees, shrubs, proposed site, airport, Asaba, Delta State. INTRODUCTION The environment according to Agbogidi and Ofuoku agriculture, the accommodation and furniture he acquires (2007) is the closest neighbour of man. Man depends as a worker/ entrepreneur, his diet and health sustaining directly and indirectly on the environment for almost systems, the armchair he relaxes on in his old age, and everything relating to growth and survival on planet earth. the coffin or casket in which he returns to Mother Earth Among the major biotic components of the environment are forest dependent. Abu and Adebisi (2002) stated that are forests and other vegetation and the wise the traditional uses of forests are basically for management of the environment depends on a better subsistence, income, environmental and social/ culture. understanding of its components. Given the dynamic Agbogidi and Eshegbeyi (2008) maintained that forests nature of the global ecosystem, environment changes, are often called the lungs of the earth for their role in the driven by man-made natural cause is inevitable. contribution to carbon sequestration and other global Economic activities and the rate of population growth ecological services yet, everywhere we look the lungs are have increased to a point where the effect of humanity on gasping. Udo (2001) noted that forest benefits include; 1), the environment can no longer be ignored (Aimufia, tangible benefits: wood products and non-wood products 2002). and; 2) intangible benefits (Table 1). Etukudo (2000) The importance of forest to mankind cannot be emphasized that forests are man’s divine treasure. overemphasized. Agbogidi and Eshegbeyi (2008) noted Aliyu (2006) stated that reasonable species of medici- that forests and forest products play vital roles in human nal species are threatened with habitat loss following life from the cradle to the grave. Aimufia (2002) heightened deforestation (Agbogidi, 2002; Agbogidi and emphasized that the cot on which the baby lies at birth, Ofuoku, 2006). Although there is great incompatibility in the buildings and furniture he uses, at the various levels urbanisation/industrialisation and agriculture, develop- of his education, his endeavours in industry and mental activities should be environmentally friendly to Agbogidi 191 Table 1. Benefits of forests. Benefits Products/Uses a) Wood products: Saw logs, veneer logs, pulpwood, poles, match wood, chew sticks, yam stakes etc. Tangible benefits b) Non-wood products: Leaves, forage, fruits and seeds, medicinal herbs, tannins (dyes), latex, resins, gums, canes/ rattans, laterite, honey, mushrooms, wildlife. a) Environmental/ protection: Soil protection against erosion, purification of air, protection of houses against windstorm, protection of water catchments, provision/ protection of wildlife habitats, windbreak against desert encroachment, cooling of the environment, protection of plants, animals and man against excessive sunrays, regulation of drought and flood, Intangible benefits amelioration of climate, harbour unique genetic resources. b) Nutrient and hydrological cycles: Helps in nutrient cycling to improve soil fertility, contribute to hydrological cycle, control of semi-metals of downstream bodies and control of ground water recharge. c) Aesthetics and education: Beautification of avenues and improvement of landscape, research ground on biodiversity, provision of tourism and recreational facilities. Source: Etukudo (2000); Udo (2001); Agbogidi and Eshegbeyi (2008). allow for sustained yield (Agbogidi and Okonta, 2009). were laid at 150 m interval. The transects ran through forest and Anthropogenic activities including farming, hunting, tree the surrounding farm fallow and 2520 × 20 m quadrants were points felling, bush burning, mining operation, petroleum along each of the transects following the procedure of Olajide et al. (2006). Assessment of forest plant species and shrub species exploitation, civil engineering construction and water producing economically valuable products subsequently followed. A exploration have been shown to impact on the forest total area of 10,000 m2 was assessed along each transect which negatively (Adeyemi and Jegede, 2002). Adelusi et al. summed up to a gross total area of about 50 ha assessed. A plant (2002) noted that urban forest reserves and enclaves species was classified as abundant or rare based on its frequency have suffered more undue depletion and degradation count in all the assessed quadrants. A plant species found in 40% and above of all the assessed quadrants was considered abundant with loss of biodiversity and renewable resources as a while a species present in < 40% of all the assessed quadrants was result of urbanization and encroachment on areas regarded rare following the procedure of Olajide et al., (2006). originnally perceived as forest reserves and estate. In the same vein, Okonkwo et al. (2002) reported that serious anthropogenic activities of man constitute great RESULTS AND DISCUSSION environmental hazards. Impact of certain projects on the vegetation of ecosystems in the tropics including Nigeria Thirty three tree species producing various economically is widespread. For example, establishment of modern valued products were assessed (Table 2). 10 of the 30 trees markets, television stations, amusement parks, housing species were observed to be rare while 23 species were estates, company sites and stadia in Nigeria and other abundant (Table 2). Fifteen species of the shrub species parts of the tropics, have led to the removal and were evaluated and twelve were identified as abundant and destruction of various economic vegetation, with the use three rare (Table 3). The economic products that are of some of these projects, yet to be discovered. harvested or collected from these plant species include nuts, The link between the environment and development fruits, seeds, leaf vegetables, bark, leaves, fodder, chew calls for an environmental impact assessment of a sticks, poles, stakes, timber, juices, resins and dyes and deemed large scale economic project that will impact on have varying use categories such as medicine, food, local the generality of the populace and Asaba in particular. construction, craft as well as socio-cultural and environ- This study has been undertaken to assess the mental values (Agbogidi and Eshegbyi, 2008; Jimoh and economically valued forest trees and shrubs on the Haruna; 2007; Idumah et al., 2008). proposed site for an airport in Asaba, Delta State with a Over exploitation, exploration and utter conver-sion of view to noting them before their utter disappearance on forest ecosystems or other land use normally result in the the conversion of the area to an airport. decimation of biological diversity as well as extinction of many valuable plant and animal species (Agbogidi, 2002; Iroko et al., 2008). The reduced population densi-ties of MATERIALS AND METHODS the studied area testified to the fact that the studied area has been under intense exploitation for commercial value The experiment was conducted at latitude 6°14’N and longitude ’ attributed mainly to man-influenced activities (anthropo- 6°49 E at the proposed site for the airport in Asaba, Delta State, Nigeria (Asaba Meteorological Office, 2008). The study was genic forces). The disappearance of many economically conducted in 2006 using line transects. Five 1 km line transects valued tree and shrub species across Nigeria is a well 192 J. Hortic. For. Table 2. Economically valued tree species of the proposed Airport site in Asaba, Delta State. S/No. Botanical name Common name Total abundance (%) Products Uses Ecological status 1. Juglaris nigra Walnut