Research Journal of Biology, 2:18– 28 (2014) www.researchjournalofbiology.weebly.com RESEARCH ARTICLE Open Access Tree Regeneration after Logging in Rain-forest Ecosystem Edward D. Wiafe Department of Environmental and Natural Resources, Presbyterian University College, Ghana, P. O. Box 393, Akropong-Akuapem, Ghana. Abstract Successful forest regeneration is critical for the sustainable management of natural forests. This study assessed natural regeneration capacity of a logged tropical forest by comparing the species composition, diversity, density and basal area at varied levels of disturbance after logging operations. The regeneration capacities of trees were analysed at three levels of disturbances: heavily disturbed, partially disturbed and undisturbed in the Asenanyo Forest Reserve in moist forest reserve in Africa. Sixty sampled plots of 25m by 25m were equally distributed randomly in each of the stratified areas. A significant difference in abundance of naturally regenerated tree species in the partially disturbed, undisturbed areas and heavily disturbed areas was observed. The density of naturally regenerated tree species in the slightly disturbed was higher than the undisturbed areas while the later recorded higher density than heavily disturbed areas. The diversity of naturally regenerated trees in the undisturbed area differed from the slightly disturbed area and heavily disturbed area while slightly disturbed and heavily disturbed areas also differed. The high density of young trees in the slightly disturbed area might be enhanced by providing conditions that promote seed germination than the undisturbed areas. However, the activities of the logging might have also destroyed seeds and cause soil compaction which might have accounted for the less number of trees as well as diversity in the heavily disturbed area. It was concluded that natural regeneration are most favored when induced slightly. It is therefore recommended that there should be a limit to the total number of trees felled in a compartment as well as the size of loading bays and the width of forest roads. Key Words: Diversity, forest disturbances, forest regeneration, forest reserve, logging. (Received: 10/02/2014; Accepted: 27/02/2014; Published: 15/03/2014) Accurate descriptions of long term chronological Introduction Tropical forests are subject to a wide range of changes in rainforest ecosystems following both natural disturbances of variable duration, intensity, and and anthropogenic disturbances can increase our frequency. In their review of major disturbances in understanding of how these systems respond to various tropical rain forests, Whitmore and Burslem (1998) disturbances (Sheil, 2001). emphasized the pervasive nature of both natural and The concept of 'direct regeneration' after human disturbances in tropical forests. They suggested disturbance to ecosystems (Boucher, 1990; Vandermeer that contemporary human activity affecting tropical et al., 1990; Yih et al., 1991), in contrast to classical forests should be viewed in the context of the panoply models of succession, suggests that those species of natural disturbance events and the dynamism that dominant in the first years after the disturbance will be characterizes tropical forest systems. In 2000, an the same as the species which were dominant before estimated 60% of the world’s tropical forest was the disturbance. The first notions of sustainable classified as degraded forest, including secondary tropical forest management were directed towards forests, degraded primary forests and degraded forest maintaining the timber yields of valuable timber land (ITTO, 2002). species. This led to the establishment of the first Post-logging disturbance regeneration and silvicultural research plots in several countries with associated variation in rainforest ecosystems is tropical rainforests by the beginning of the twentieth complex, which involve a variety of responses including century (Lamprecht, 1989; Dawkins and Philip, 1998; species progressive replacement sequences (Hopkins, Bertauld and Kadir, 1998; Chazdon and Whitmore, 1992; Sheil, 2001). Models for species succession and 2002). The research focused mainly on identifying the underlying processes that involve changes in means to enhance the growth of commercial tree biomass, species diversity and homeostasis are well species while suppressing the unmerchantable species documented (Odum, 1970; Connell and Slatyer, 1977; (Lamprecht 1989, Dawkins and Philip 1998). With Brokaw and Busing, 2000). increasing environmental awareness, forest managers came to understand that there are many other valuable *Corresponding author: services provided by forests in addition to timber [email protected] production that must also be taken into consideration. Climate change has been embraced and measures are being taken to adapt in all aspects of its consequences. 18 Copyright © 2014 RJB Res. J. Biol., 2014 [2:18-28] E-ISSN: 2322-0066 The atmosphere delivers both resources such as rain, of various tree species composition of the natural sun, wind and hazards such as hurricanes, blizzards, regeneration after exploitation. droughts; to ecosystems and societies. Through autonomous and/or planned adaptation, species and Materials and methods individuals, ecosystems and societies, are fashioned to Study area a considerable extent by these climatic constraints. The study was conducted in the Asenenyo River Forest Ecosystems and our human cultures and economies are Reserve which can be found in the Nkawie Forest ‘tuned’ to the climate in which they evolve (Green et. District of the Ashanti Region (Ghana); located on al., 2003). between Latitude 6o 17’ -6o36’N and Longitude 2o 03’- The major concern has been that the globe is 2o 16’ W. It is wholly owned by the Golden stool but undergoing climate change at unprecedented rates and under caretaker stools or Chiefs of Nkwaie-kuma, the real situation is that temperatures are rising and Nkawie-Panin, Nyinahin, Domi-Kwamiago, the global weather patterns are changing. Patterns of MansoNkwanta and Akwamu. It covers an area of about seasonality and the intensity and frequency of more 228.0 km2 or 22,800 hectares and a perimeter of 100.26 extreme events, such as hurricanes and droughts are km. The vegetation type of Asenanyo River Forest being altered. There has been a 10% increase in Reserve is the Moist Semi Deciduous North West atmospheric CO2 concentration over the past four subtype and plant association of the Celtis – decades and the mean global temperature has o Triplochiton. According to Forest Services Division increased by about 0.5 Cover the same period and the (2010), it was constituted as Forest Reserve in the year temperature in tropical rainforest regions are projected o o st 1940 and currently it is under Forest Management Unit to increase between 2 and 5 by the end of 21 (FMU) 37 of The Forest Management Unit categories. century (Malhi and Wright, 2004). Rainfall projections The dominant flora species were Celtis mildbraedii are less certain and more variable geographically, yet (Esa), Triplochiton scleroxylon (Wawa), probably most crucial for anticipating climate change Entandrophragma spp. and Thaumatococus spp. impact on rain forests. Patterns of regional landuse (Aworomoo) and that of the fauna were Tragelaphus affect the changes in atmospheric conditions and scriptus (Owansane), Tropicranus albocristatus (White- climate. For instance atmospheric contribution of crested hornbill) and Dendropicos gabonensis nitrogen inputs from atmospheric deposition of (Abobonua). nitrogen has increased within tropical regions and its Asenanyo river forest reserve has a low lying impact on growth is complicated and remains uncertain terrain with few hilly outcrops notable amongst these (Ghazoul and Sheil, 2010). hills is the Sumtwitwi Range. It is also drained by the In Ghana, between 10-25% of the total area of Asenanyo River from which the forest reserve derived Ghana’s managed forests is affected by logging roads its name. It has an average height of about 152.40m to and tracks, some of which are characterized by soil 182.88m above sea level (Figure 1). It has twenty (20) erosion and poor plant regeneration (Hawthorne and admitted farms and one settlement namely Akotaa Abu-Juam, 1993). In his work on post-logging town ship which covers an area of about 955.70 regeneration study in the Bia South Game Production hectares. Asenayo River Forest Reserve has seven (7) reserve, Hawthorne (1993) observed that gap size main management categories namely Swamp influences the extent and type of regeneration of forest Sanctuaries, Hill Sanctuaries, Convalescence, Research, tree seedlings. Yet he noted that logging operations Plantation, Timber Production and Admitted farms. The showed few signs of having any adverse effect on management prescriptions for these management regeneration in that reserve. categories include pillaring and conservation of flora The goal of this study was to investigate whether and fauna, protection of high elevations, protection of the removal of tree species would be replaced naturally areas for regeneration and biodiversity areas, by the same or different species as timber or would be evaluation of Tropical Shelterwood system, area to be the balance of species likely to be upset by logging. It converted into plantations, growth potential of Teak as further examined the tree species composition of the well as extraction of timber and non-timber forest various levels of disturbances