Forest-savanna Transition Zone Research Articles

Efficacy and economic comparison of weed management in tomato

ABSTRACT Weed interference in tomato (Solanum lycopersicum L.) reduces fruit yield and economic return under tropical conditions for smallholder growers who pay for labor. Field experiments were conducted in a tropical forest-savanna transition zone to evaluate the efficacy and economic benefits of hand weeding, herbicides and their combination in tomato cultivation. Pre-emergence application of propaben® (metolachor+prometryn) and butachlor, each at 2 kg∙ha−1, plus hand weeding at 40 days after transplanting reduced weed density and biomass, and increased weed control efficacy (57–64%) less than the weed-free check (100%) and better than two hand weedings (45%), or either herbicide applied alone (34–38%). Propaben® or butachlor plus hand weeding increased number of leaves and branches, number of fruit and fruit yield of tomato similar to the weed-free check and better than two hand weedings, or either herbicide applied alone. Although the weed-free check gave similar fruit yield, propaben® or butachlor plus hand weeding was 37–44% higher in net return. Application of propaben® or butachlor alone gave comparable net returns to two hand weedings and the weed-free check, but had a 61–88% higher cost-benefit ratio. Multiple hand weeding did not guarantee the highest yield or net return and increased cost of production. The combination of propaben® or butachlor plus hand weeding will provide higher tomato yield and net return through efficient weed control at relatively lower cost.

Changing Agricultural Practices and Indigenous Food Crops in the Upper Afram Basin of Ghana

The Forest Savanna Transition zone within which the Upper Afram basin lies, account for a wide variety of food crops and plant species. This study examined the effects of changing ag­ricultural practices on cultivation and availability of indigenous food crops within the basin. Qualitative data obtained from 240 farmers through individual interviews and Focus group dis­cussions were analyzed thematically. The study revealed that even though the farmers employed the traditional mixed cropping system, the widespread use of agro-chemicals in the study area was limiting the practice of intercropping. This accounts for the current dominance of mono cropping system in the study area. These changes have affected the cultivation of a wide variety of indigenous foods within the basin. The uncontrolled use of agro-chemicals constituted one of the major agronomic constraints affecting the cultivation of these crops. Adequate technical support services to effectively control agrochemical abuse among the local farmers will, there­fore, be required. Increased sensitization on the need for local farmers to refocus and maintain some of the traditional agricultural practices that ensured the cultivation of a wide variety of indigenous food crop varieties (NUCS) in their farms is also suggested.

Evaluation of yield and yield related traits of exotic grain amaranth (<i>Amaranthus</i> spp.) accessions

Amaranth grain yield varies widely in response to environment, weather conditions, species, genotype and production techniques. With appropriate varieties, yields of grain amaranth can be improved. The objective of this study was to assess the extent of yield variability in exotic grain amaranth accessions between locations. Field trials involving 28 accessions as treatments were conducted at two locations namely the Vegetable Research Farm of the National Horticultural Research Institute (NIHORT), Idi-Ishin Ibadan and the Teaching & Research Farm of Ladoke Akintola University of Technology (LAUTECH), Ogbomoso. The two locations are in Oyo State, South-West, Nigeria, with Ibadan typifying Forest-Savanna transition zone and Ogbomoso Derived Savanna zone. The field trials were undertaken from August to December 2013. The 28 accessions were replicated three times in a randomized complete block design in each location. Data were collected on growth and yield parameters; inflorescence length, inflorescence weight, 1000-grain weight, grain production efficiency, and grain yield. Variability existed among the accessions of grain amaranth. There were significant ( p < 0.05) differences in grain yield of the accessions. Accessions 74-43, RRC1351, RRC399, RRC8 and RRC551 (all of which are Amaranthus Caudatus spp.) produced higher grain yields in both locations compared to the rest of the accessions. The top high-yielding accessions included RRC1351 (1.9 t ha −1 ), RRC399 (1.8 t ha −1 ), 74-43 (1.7 t ha −1 ), RRC8 (1.4 t ha −1 ) and RRC551 (1.3 t ha −1 ). Yield of grain amaranth was significantly lower in the more humid Ibadan than the less humid Ogbomoso. Keywords: grain production efficiency, inflorescence length, weight and location

Effects of planting dates on the growth and grain yield of two indigenous varieties of pearl millet (Pennisetum glaucum (L.) R.Br.) in a forest-savanna transition zone of Edo State, Nigeria

Effects of planting dates on the growth and grain yield of two indigenous varieties of pearl millet was carried out at the Teaching and Research Farm, Ambrose Alli University, Ekpoma. The experiment was a 2 × 5 factorial scheme fitted into a randomized complete block design with the two varieties of pearl millet (‘Gero Bida’ and ‘Gero Badeggi’) and five planting dates (April, May, June, July and August) replicated three times. The results obtained showed that delays in planting date significantly reduced growth in pearl millet examined. Similar pattern was observed on days to 50 % flowering and grain maturity. Improved growth with early sowing could have allowed increased availability of assimilates that later supported reproductive growth. These assimilates were remobilized under unfavourable climatic condition in the late cropping season to the reproductive structures. ‘Gero Badeggi’ sown in April, had significantly, the highest growth in the measured characters than ‘Gero Bida’ sown in August and other dates. ‘Gero Badeggi’ planted in May had the highest total grain yield (9.33 t ha-1) while ‘Gero Bida’ planted in July had the smallest (4.27 t ha-1). Therefore, ‘Gero Baddegi’ planted in May is a better variety for pearl millet grain production in Ekpoma.

Impact of cashew induced land use change on vegetation carbon stocks in the forest savanna transition zone

Impact of cashew induced land use change on vegetation carbon stocks in the forest savanna transition zone

Influence of Five Years of Tillage and Poultry Manure Application on Soil Properties and Ginger (Ziginber officinale Roscoe) Productivity

Tillage and use of organic manure are essential agronomic practices that affect soil properties and have a direct impact on soil sustainability and crop productivity. Hence, a five-year (2012 to 2016) field trial was carried at two sites (Owo — site 1 and Uso — site 2), in the forest-savanna transition zone of southwest Nigeria to assess the effect of tillage and poultry manure on soil physical and chemical properties, growth and yield of ginger (Zingiber officinale Roscoe). The study was a 2 × 5 × 5 factorial experiment with three replicates. The treatments were five tillage methods; zero tillage (ZT), manual ridging (MR), manual mounding (MM), ploughing plus harrowing (P+H), and ploughing plus harrowing twice (P+2H) and five levels of poultry manure (PM) (0, 5.0, 10.0, 15.0, 20.0 t ha−1). Soil bulk density (BD) increased, while soil water content (WC) decreased with increase in tillage intensity, whereas soil OM, N, P, K, Ca, and Mg reduced with increase in tillage intensity, thus ZT conserved soil OM and nutrients the most, and increased nutrient uptake. Soil OM and nutrient concentrations was lowest under the P+2H treatment due to leaching, oxidation, and increased biological activity. The ZT, MR, and MM treatments prompted quicker growth and higher rhizome yield. As PM increased from 0 to 20.0 t ha−1 soil BD and WC tend to improve and soil pH, OM, N, P, K, Ca, and Mg increased. The 15.0 t ha−1 PM gave the highest soil K, Ca, and Mg values. Site 1 had significantly higher growth and yield parameters of ginger compared with site 2. Growth and yield parameters of ginger increased with increase in PM level up to 15.0 t ha−1. Among all tillage cum manure treatments, ZT+15.0 t ha−1 PM gave the highest values of growth and yield parameters of ginger.

Assessment of Some Production Practices on the Quality of Cocoa Beans (Theobroma cacao): A Case Study of Forest Savanna Transition and Semi-Deciduous Rainforest Zones of Ghana

Assessment of Some Production Practices on the Quality of Cocoa Beans (Theobroma cacao): A Case Study of Forest Savanna Transition and Semi-Deciduous Rainforest Zones of Ghana

Effects of 3-year cultivation on the soil nutrient status in a tropical forest and savanna of Central Africa, as determined by the microbial responses to substrate addition

ABSTRACTThe forest–savanna transition zone is widely distributed on nutrient-poor Oxisols in Central Africa, and a population explosion has led to the rapid cultivation of these vegetation types in this zone. To reveal and compare the effects of short-term (3 years) cultivation on the soil nutrient status of the forest and savanna vegetation in this area, we evaluated microbial nutrient limitation and availability by conducting hourly measurements of soil microbial respiration after the addition of glucose in combination with nitrogen (N) and/or phosphorus (P) to soils that were collected from a forest site (FOR), a savanna site (SAV), as well as cropland for 3 years derived from a forest (Crop-F) and a savanna (Crop-S), in eastern Cameroon. The N addition had little effect on the pattern of microbial respiration rate for the FOR and Crop-F sites, indicating N rich for microbes. In contrast, N addition resulted in the increases in maximal respiration rates after the exponential increase for the SAV and Crop-S sites, indicating microbial N limitation, and cultivation accelerated the soil N depletion. Furthermore, we observed that P addition resulted in the increase in the maximal respiration rates, indicating microbial P limitation for all sites, except for FOR site. Since the cultivation significantly affected the microbial properties only in the forest ecosystem, such as the increase in the microbial specific growth rate and the decreased microbial C:N and C:P ratios, these changes would induce the P limitation for Crop-F. These results indicate that (1) the FOR site was a N-rich ecosystem for soil microbes, and 3 years of cultivation in the Crop-F site did not alter the high soil N status but induced microbial P limitation, with the changes in the microbial properties, and that (2) the SAV site was N and P limited for soil microbes, and 3 years of cultivation clearly decreased the soil N availability.

Seasonal Polyphenism in Bicyclus dorothea (Lepidoptera: Nymphalidae) Across Different Habitats in Cameroon.

Many organisms exhibit changes in phenotypic traits as a response to seasonal environmental variation. We investigated the role of habitat in generating seasonal polyphenism in different populations of the light bush brown butterfly Bicyclus dorothea (Cramer, 1779) (Lepidoptera: Nymphalidae) in Cameroon. Butterflies were caught during the wet and dry seasons across four localities representing two distinct habitats, namely forest and ecotone (forest-savanna transition zone) over a 2-yr period (2015-2016). We found distinct variation in the wing pattern characteristics of butterflies in response to seasonality and habitat. Specifically we observed that: 1) all wing characters are not seasonally plastic in B. dorothea; 2) populations from ecotone tend to be more variable, with individuals exhibiting wings with large spots during the wet season and very reduced spots in the dry season while in forest populations, individuals exhibit wings with large spots during the wet season, but in the dry season, spots are not as greatly reduced as their ecotone counterparts; 3) this polyphenism in B. dorothea alternated consistently during the wet and dry seasons over the 2 yr of sampling. Bicyclus species have become a textbook example of seasonal polyphenism while this study extends this model system to the unique forest-ecotone gradient of Central Africa and demonstrates the complexity of seasonal forms in different habitats.

Nitrogen and weed management in transplanted tomato in the Nigerian forest-savanna transition zone

Abstract Weed infestation and inherent low soil fertility are among primary reasons for low yields of tomato in Nigeria. Field trials were carried out during the wet season of 2015 and 2016 to evaluate yield response of tomato to nitrogen (N) application and weed control methods in the forest-savanna transition zone of Abeokuta, Nigeria. Positive relationship exists between growth of weed species and increase in N application. Across the years of study, increase in N up to 90 kg/ha increased weed density by 11–25%, however, the increased N gave the transplanted tomato competitive advantage and thus enhanced weed smothering. Pre-transplant application of butachlor (50% w/v) or probaben® (metolachlor 20% w/v + prometryn 20% w/v) each at 2.0 kg a.i/ha followed by supplementary hoe weeding at 6 weeks after transplanting (WAT) significantly reduced weed density by at least 15% and increased fruit yield of tomato by at least 32%, compared to use of the pre-transplant herbicides alone, across both years of study. The greatest tomato fruit yield of 12.2 t/ha was obtained with pre-transplant application of butachlor at 2.0 kg a.i/ha followed by supplementary hoe weeding at 6 WAT, averaged for both years. In general, this study suggests that increased application of N up to 90 kg/ha, and complementary weed control by pre-transplant herbicide and hoe weeding at 6 WAT would improve yield of tomato in the forest-savanna transition zone of Nigeria.

Soil phosphorus of stable fraction differentially associate with carbon in the tropical forest and savanna of eastern Cameroon

ABSTRACTThe forest–savanna transition zone, which contains nutrient-poor soils (Oxisols), is found throughout central Africa. To evaluate the effect of deforestation on soil phosphorus dynamics, which regulate the plant growth in this area, we quantified the relationship between phosphorus (P) and carbon (C) in different fractions and compared their relationship to forest and savanna (deforested vegetation) in eastern Cameroon. We analyzed the P, C, and nitrogen (N) contents of soil using the physical fractionation method (0.25–2.0 mm as macro-particulate organic matter [M-POM]; 0.053–0.25 mm as micro-POM; and <0.053 mm as Clay+silt) in different land management (young and old forests and annual and perennial grass savannas at 100-cm soil depth). We found larger soil P stock in forests (4.7–4.9 Mg P ha−1) than that in savannas (3.4–4.0 Mg P ha−1), though soil C and N stocks were similar between the vegetation. We also observed lower soil P stock in the active fraction (M-POM) with its higher C:P and lower C:N ratio in forest surface layer (0–10 cm), indicating that forests have lower available soil P. By using the regression analysis, we found a clear relationship between P and C in the stable fraction (Clay+silt) of the upper layer (0–40 cm) for each land management, and the coefficient of the regression was clearly different between the forest and savanna. It indicates that a more chemically complex organic P form of the stable fraction exists in forest soil than in savanna soil. These results indicate that the deforestation (savannazation) affect the active and stable P dynamics and it should cause the lower soil P stock of the upper layer in savanna than in forest.

English

A grain yield trial was conducted in three locations in Southern Ghana. The objective of the trial was to determine the effects of genotype by environment interaction on 90 early maturing hybrid maize. The trial was conducted in Fumesua, Ejura and Kpeve; representing the forest, forest-Savanna transition and coastal-Savanna transition zones respectively. The analysis of variance for grain yield demonstrated that genotypic and environmental effects were highly significant (P&lt;0.001) while their interaction was significant (P&lt;0.005). The genotypes contributed 34.4% of total sum of square percentage while environment contributed 31.1% of the total sum of square of the variance. The genotype main effect plus genotype &times; environment interaction biplot explained 85.2% of total variation of the sum of squares for grain yield. P40, P16, P78, P53, P41 P9 and P3 were identified by GGE biplot analysis as high yielding and stable genotypes while P20, P80, P22, and P15 were low yielding but very stable genotypes. On the other hand, P59, P41, P16, P26 and P50 were high yielding but not stable and was recommended that genotypes with broad range adaptability can be tested on farmers field for possible release. &nbsp; Key words: Tropical maize early maturing (TZEI), Genotype &times; environmental interaction (GGE) biplot, hybrid, Fumesua, Ejura, Kpeve trial, environment, treatment.

Impact of Poultry Manure and NPK Fertilizer On Soil Physical Properties and Growth and Yield of Carrot

Abstract A field experiment was conducted in the forest-savanna transition zone of Nigeria from May to July 2014 and September to November 2015 to determine the impacts of poultry manure (PM) and NPK fertilizer on soil physical properties, and growth and yield of carrot (Daucus carota L.). The five treatments included no manure or fertilizer (control); 10, 20, and 30 megagrams (Mg)·ha-1 of PM; and 300 kg·ha-1 of 15 N-15 P-15 K fertilizer. All levels of PM reduced soil bulk density and temperature, and improved total porosity and moisture content compared to the NPK fertilizer and the control. Plant height, number of leaves, root diameter, root length, and fresh root yield in the PM and NPK fertilizer treatments were improved compared to the control. Growth and yield parameters of carrot plants treated with 20 and 30 Mg·ha-1 PM were higher than the other treatments. The 10 Mg·ha-1 PM and NPK fertilizer treatments produced similar growth and yield responses. There was an interaction for year (Y) × fertilizer (F) on plant height, number of leaves, and fresh root yield. Relative to the control 10, 20, or 30 Mg·ha-1 PM and NPK fertilizer increased fresh root yield of carrot by 39.9%, 62.0%, 64.9%, and 37.3%, respectively. The 20 Mg·ha-1 PM treatment best improved soil properties and carrot productivity as indicated by the benefit-to-cost ratio.

Farmers’ perception of water contribution to household and farming system in the Offinso North District of Ghana: rainfall a critical climatic factor

Water resources are increasingly under pressure from population growth, economic activity, and climate change/variability. Using survey and community meetings, the paper analyzed water resources accessible to three farming communities in the Offinso North District and the effects of rainfall changes on their farming livelihood. The study revealed that the households depended on water from three sources, namely: groundwater through boreholes for drinking and domestic use; surface water through streams for drinking, domestic use and irrigating vegetable farms and atmospheric water (i.e. rainfall) for farming. For about 80% of the respondents, changes in rainfall pattern adversely affected their crops yield which has implication on their livelihoods. Access to irrigation facilities was virtually absent. Also, the non-application of water harvesting techniques for farming thus left these smallholder farmers to the ‘mercies of the weather’. Education on climate change and adaptation strategies coupled with technological know-how on water management is recommended for the communities in this forest-savanna transition zone where abrupt changes in rainfall pattern are new to their livelihoods. Keywords: Water Resources, Rainfall, Climate Change, Farming Households, Farm Productivity

Winners and losers: tropical forest tree seedling survival across a West African forest-savanna transition.

Forest encroachment into savanna is occurring at an unprecedented rate across tropical Africa, leading to a loss of valuable savanna habitat. One of the first stages of forest encroachment is the establishment of tree seedlings at the forest–savanna transition. This study examines the demographic bottleneck in the seedlings of five species of tropical forest pioneer trees in a forest–savanna transition zone in West Africa. Five species of tropical pioneer forest tree seedlings were planted in savanna, mixed/transition, and forest vegetation types and grown for 12 months, during which time fire occurred in the area. We examined seedling survival rates, height, and stem diameter before and after fire; and seedling biomass and starch allocation patterns after fire. Seedling survival rates were significantly affected by fire, drought, and vegetation type. Seedlings that preferentially allocated more resources to increasing root and leaf starch (starch storage helps recovery from fire) survived better in savanna environments (frequently burnt), while seedlings that allocated more resources to growth and resource‐capture traits (height, the number of leaves, stem diameter, specific leaf area, specific root length, root‐to‐shoot ratio) survived better in mixed/transition and forest environments. Larger (taller with a greater stem diameter) seedlings survived burning better than smaller seedlings. However, larger seedlings survived better than smaller ones even in the absence of fire. Bombax buonopozense was the forest species that survived best in the savanna environment, likely as a result of increased access to light allowing greater investment in belowground starch storage capacity and therefore a greater ability to cope with fire. Synthesis: Forest pioneer tree species survived best through fire and drought in the savanna compared to the other two vegetation types. This was likely a result of the open‐canopied savanna providing greater access to light, thereby releasing seedlings from light limitation and enabling them to make and store more starch. Fire can be used as a management tool for controlling forest encroachment into savanna as it significantly affects seedling survival. However, if rainfall increases as a result of global change factors, encroachment may be more difficult to control as seedling survival ostensibly increases when the pressure of drought is lifted. We propose B. buonopozense as an indicator species for forest encroachment into savanna in West African forest–savanna transitions.

Effect of methods and time of poultry manure application on soil and leaf nutrient concentrations, growth and fruit yield of tomato (Lycopersicon esculentum Mill)

In order to obtain maximum economic value of plant nutrients in poultry manure and increase in tomato yield, field experiments were conducted at Owo, southwest Nigeria, during 2012 and 2013 early cropping seasons to study the effect of two methods (broadcasting on the soil surface and the incorporated) and four times (3weeks before transplanting (3 WBTP), 0week at transplanting (0 WATP), 3weeks after transplanting (3 WATP), and 6weeks after transplanting (6 WATP) of poultry manure (PM)) applications on soil chemical properties, leaf nutrient concentrations, growth and yield of tomato. The eight treatments were factorially arranged in a randomized block design with 3 replications. Results showed that PM incorporated into the soil produced higher soil organic matter and soil and leaf N, P, K, Ca, Mg, growth and yield (0.9tha−1) of tomato compared with broadcast method. Also PM applied at 3 WBTP had higher leaf nutrient concentrations and better growth and yield of tomato compared with 0 WATP, 3 WATP and 6 WATP. The higher yield of 3 WBTP was adduced to better synchrony between crop demand and nutrient supply. Using the mean of the two years, 3 WBTP increased tomato fruit yield by 4.0, 2.8 and 1.5tha−1 compared with 6 WATP, 3 WATP and 0 WATP, respectively. This yield difference can be economical on large scale tomato production. Therefore application of PM at 3 WBTP with incorporated method is recommended for tomato cultivation in the forest-savanna transition zone of southwest Nigeria.

Agro-Diversity in the Forest-Savannah Transition Zone of Ghana: A Strategy for Food Security against Climatic and Socio-Economic Stressors

&lt;p class="1Body"&gt;Food security is a major issue affecting about 239 million people in Sub-Saharan Africa. Therefore, local ecosystems-based adaptive strategies for reducing the impact of climate change and other stressors on food production systems are very relevant in the national food security agenda. This study assessed how farmers in communities of the environs of the Kogyae Strict Nature Reserves in the forest-savanna transition zone of Ghana exploit a range of options for food production that spread and reduce risks and ensure sustainability of the local environment. Through a cross-sectional survey involving focus group discussions, institutional data search and on-site observations, the study investigated different ways to which the natural diversity of the environment has been used by farmers to enhance farm productivity and farmer income. The study observed that climate variability, land expropriation for protected area establishment, inappropriate use of farm technology and low pricing for farm produce pose as major threats to sustainable agriculture in the area. These constraints have compelled farmers to adopt a range of agro-diversity practices for increased farm productivity and income. They include introduction of new crop varieties, adoption of innovative farm management practices, diversified farm fields and sequential cropping systems. The study noted that the diversified systems have boosted farmer productivity and incomes and contributed to their socio-cultural needs. The study recommends greater crop intensification through the use of appropriate technologies and improved access to markets to consolidate farmer gains and livelihoods as well as ensuring food and nutritional security.&lt;/p&gt;

Agroecological Niches as Ecosystem-Based Adaptive Option to Environmental Change in the Forest-Savanna Transition Zone of Ghana

&lt;p&gt;Generally, local farmers are able to adapt to environmental change (and developments in socio-economic conditions) by engaging in a range of creative practices of on-farm management, use of improved crop varieties and adoption of new technologies. However in the past few decades, there has been growing interest in other adaptive options with the potential of addressing household food security and the multiple dimensions of sustainable agriculture. This study therefore examined the use of niche environments in the agricultural landscape as ecosystem-based adaptive strategy to environmental change among 102 farmers of 9 fringe communities of the Kogyae Strict Nature Reserve of the forest-savanna transition zone in Ghana. The study noted the increasing shift from maize cultivation to rice production using marshy areas and low-lying parts of farm fields and farms. The farmers mentioned climatic, ecological and other socio-economic reasons for this trend. They cited growing insecurity associated with maize production due to changing rainfall pattern and reduction in rainfall amounts, and changes in land cover and soil conditions. Additionally, they emphasized the relative ease with which they are able to store rice and the willingness of padi buyers to visit the villages in spite of the poor nature of the roads. The study advocated for greater institutional support to boost local rice production in order to reduce the country’s heavy dependence on imports.&lt;/p&gt;

Effects of vegetation on soil microbial C, N, and P dynamics in a tropical forest and savanna of Central Africa

The forest–savanna transition zone is widely distributed on nutrient-poor oxisols in Central Africa. To reveal and compare the nutrient cycle in relation to soil microbes for forest and savanna vegetation in this area, we evaluated seasonal fluctuations in microbial biomass carbon (MBC), nitrogen (MBN), and phosphorus (MBP) for 13 months as well as soil moisture, temperature, soil pH levels, and nutrients for both vegetation types in eastern Cameroon. Soil pH was significantly lower in forest (4.3) than in savanna (5.6), and soil N availability was greater in forest (87.1mgNkg−1 soil) than in savanna (32.9mgNkg−1 soil). We found a significant positive correlation between soil moisture and MBP in forest, indicating the importance of organic P mineralization for MBP, whereas in savanna, we found a significant positive correlation between soil N availability and MBP, indicating N limitation for MBP. These results suggest that for soil microbes, forest is an N-saturated and P-limited ecosystem, whereas savanna is an N-limited ecosystem. Additionally, we observed a significantly lower MBN and larger MB C:N ratio in forest (50.7mgNkg−1 soil and 8.6, respectively) than in savanna (60.0mgNkg−1 soil and 6.5, respectively) during the experimental period, despite the rich soil N condition in forest. This may be due to the significantly lower soil pH in forest, which influences the different soil microbial communities (fungi-to-bacteria ratio) in forest versus savanna, and therefore, our results indicate that, in terms of microbial N dynamics, soil pH rather than soil substrate conditions controls the soil microbial communities in this area. Further studies should be focused on soil microbial community, such as PLFA, which was not evaluated in the present study.

English

A proposed timber plantation site (approximately 1,900 hectares) located in the forest-savanna transition zone of the Ashanti Region, Ghana was surveyed. The objectives of the study were (1) to analyze the present stand structure (2) and to assess the tree regeneration potential on the plantation site. The forest assessment used systematic sampling design which revealed an open and fire disturbed stand structure with an estimated average basal area per hectare (&alpha; = 0.05) of 9.89&plusmn;1.94 m2. The forest vegetation comprises of a single layer and features an average top height (&alpha; = 0.05) of 17.7 &plusmn; 0.8 m. The assessment of the tree species composition indicated a relatively homogeneous floristic composition with an average tree species number per sample plot of 10.0&plusmn;1.0. A total of 65 tree species belonging to 48 genera and 25 families was recorded. Tree regeneration from seeds and resprouts recorded an average number per hectare (&alpha; = 0.05) of 3.884 &plusmn; 746 with a total of 38 species regenerating. The remnant forest vegetation is assumed to be in a regressive succession stage towards savanna vegetation. A conversion of the remnant forest vegetation to production forest seems to be possible, if the existing socio-economic pressure on the forest resources can be reduced and wildfires can be prevented. &nbsp; Key words: Savanna, fire, forest regeneration, stand structure, Ghana.