Moist Semi-deciduous Forest Zone Research Articles

Drivers of land use land cover change and intensity analysis of land transformation in the moist semi-deciduous forest zone of Ghana: Case of Bobiri Forest Reserve and its environs

Understanding land cover transformation over time and space is crucial for comprehending ecological challenges, particularly in environmentally vulnerable areas. In Sub-Saharan Africa, the demand for fuel, food, and fibre is expected to significantly expand croplands, resulting in the degradation of natural ecosystems. This research presents a spatiotemporal analysis of land-cover change in the Bobiri forest and its surrounding areas in Ghana's moist semi-deciduous forest zone. The study’s main objectives were to identify the drivers of land-cover change, and to analyse the intensity of land transformation from 1986 to 2022 in the study area. The methodology used measured land-cover changes at different levels, including intervals, categories, and transitions. The findings indicate that the annual rate of land change was higher from 1986 to 2007 (1.64%) compared to the period from 2007 to 2022 (1.04%). Additionally, the analysis at the category level reveals that the increase in cropland and non-vegetated areas during both time intervals was higher than the uniform intensity. The analysis at the transition level suggests that most of the cropland gains originated from non-vegetated areas during both periods. There is also evidence of localized increases in closed forests, likely due to afforestation policies implemented by the Ghanaian government. However, overall, there has been a decline in closed forests over the entire timeframe, with an annual rate of change of -1.25%. This study contributes valuable data for enhancing our understanding of the scale and direction of land-cover change, which is essential for developing policies aimed at mitigating the impact on local livelihoods and the environment at national and sub-national levels.

A Comparative Study of Carbon Storage in Two Cocoa (Theobroma cacao) Shade-Types and a Teak Plantation in the Moist Semi-deciduous Forest Zone of Ghana.

on life, it is important that steps are taken to mitigate its effects. With the intensification of cocoa production, there has been a shift in traditional cocoa farming over the years leading to the removal of shade trees, hence, removal of carbon sinks. This study was carried out to compare the amount of carbon stored in cocoa ecosystems to that of a 20 years teak plantation and to calculate the trade-off of carbon between the two systems. Cocoa farms of similar ages (20 years) were selected in which three-subplots were demarcated on each farm at Piase in the Bosomtwe District. Tree Diameter at Breast Height (DBH) was measured and soils samples were collected and analyzed for organic carbon percentage and bulk density. One-way Analysis of Variance was used to analyze above and belowground tree carbon and two-way analysis of variance was used to analyze soil organic carbon stored. Teak plantation recorded higher carbon stock (739.33±2.24 Mg C.ha-1) compared to full sun cocoa (9.36±2.24 Mg C.ha-1). Soil organic carbon across the three farms showed significant (p = 0.0010) variations with depths. The 0-20 cm soil depth stored significantly more (p = 0.0000) organic carbon compared to 20-40 cm soil depth. Total soil carbon stored revealed significant differences amongst the various farms with the full sun (40.857±0.52 Mg C.ha-1) being the least whilst the teak plantation stored the highest (72.42±0.52 Mg C.ha-1). Total carbon (above-ground tree carbon + below-ground tree carbon + soil organic carbon) showed significant difference (p= 0.0000) between land use types with shaded cocoa farm (74.3±0.89 Mg C.ha-1), full sun cocoa farm (32.02±0.89Mg C.ha-1) and that of the teak plantation (950.91±0.89 Mg C.ha-1) respectively. Traditional cocoa ecosystem (shaded cocoa farms) has the potential to store carbon significantly higher than that of the full sun systems.

Effects of Boiled Water Pre-Sowing Treatment on the Germination and Early Growth Performance of Faidherbia albida in Three Ecological Zones of Ghana

Aims: To identify an appropriate boiled water pre-sowing treatment regime for improved germination, survival and early growth performance of Faidherbia albida (Delile) A. Chev., in three ecological zones of Ghana.
 Study Design: The design was a Completely Randomized Block Design (CRBD) in three replicates, where the three different ecological zones were considered as blocks.
 Place and Duration of Study: The study was conducted in Bolgatanga (Guinea Savannah Zone), Abofuor (Forest-Savannah Transitional Zone), and Kumasi-Mesewam (Moist Semi-deciduous Forest Zone) between April 2017 and April 2018.
 Methodology: Matured seeds of F. albida were harvested, dried and cleaned. For each treatment replicate, one hundred F. albida seeds were immersed in boiled water (100ºC) for 0, 30, 60, 120, 180 and 300 seconds and then, soaked in water at room temperature for 24 hours. Seeds were then sown in drills on well prepared seed beds, and then observed for germination. Watering was done to keep the soil moist until the onset of germination.
 Results: There were significant interactive effects between ecological zones and pre-sowing treatments with respect to Final germination percentage (P<0.001), Germination rates (P<0.001) and Survival percentage (P=0.007). Root length (P=0.040), total plant length (P=0.040) and Number of leaves (P<0.001) also exhibited significant interactive effects due to ecological zones and pre-sowing treatments. Roots were significantly longer in the GSZ than in the more humid ecological zones whereas stems were significantly longer in the MSFZ than in the drier GSZ.
 Conclusion: Different durations of F. albida seeds in boiled water had different effects on germination and growth in the different ecological zones.

Biochar and inorganic nitrogen fertilizer effects on maize (Zea mays L.) nitrogen use and yield in moist semi-deciduous forest zone of Ghana

Maize (Zea mays L.) is a major nitrogen consuming crop, as nitrogen is considered as an important determinant of its grain yield. Though inorganic fertilizer is widely recommended, the problem of high cost and inaccessibility limit its usage by resource poor farmers. Biochar application provides a new technology for both soil fertility and crop productivity improvement. With limited research on the suitability of biochar for soil improvement practices in Ghana, our objective was to determine the synergistic effect of biochar and inorganic fertilizer on the nitrogen uptake, nitrogen use efficiency, and yield of maize. Field experiment was conducted in Ghana, KNUST, in the major and minor raining seasons. Biochar was applied at 0, 5, 10, 15, and 20 t ha−1 and fertilizer N applied at 0, 45, and 90 kg ha−1. The results showed significantly (p < .05) higher N uptake, N use efficiency and yield of maize when biochar was applied with fertilizer N compared to both the control and sole N fertilizer plots. Biochar applied at 10 t ha−1 supplemented with 45 kg N ha−1 increased N uptake by 200%, and grain yield by 213% and 160% relative to the control in the minor and major rainy seasons, respectively. The greater yield of maize recorded on biochar-amended soils was attributed to the improved N uptake and nitrogen use efficiency. In conclusion, our finding suggests that the application of combined biochar and inorganic N fertilizer is not only ecologically prudent, but economically viable and a practicable alternative to current farmers’ practice of cultivating maize in Ghana.

New aboveground biomass and nitrogen yield in different ages of gliricidia (Gliricidia sepium Jacq.) trees under different pruning intensities in moist semi-deciduous forest zone of Ghana

Pruning of woody perennials is extensively practiced among farmers in agroforestry. We investigated different pruning frequencies on new aboveground biomass, nitrogen concentration and nitrogen yield on gliricidia (Gliricidia sepium) trees of different ages. Two sites were selected in Ghana where gliricidia trees were intercropped in cocoa agroforestry system. One site had young (within 5 years) trees whilst the other had old (above 10 years) trees. A total of 15 gliricidia trees were selected from each site. Five pruning regimes (2, 4, 6, 8 and 10 months) was assigned to each tree and replicated 3 times. The result showed that shoot biomass among the different pruning regimes varied significantly (P < 0.05) in both age groups, with more biomass found in the shoot axes than in leaves as pruning delayed. Maximum biomass in old trees was 67.15 kg/tree at 8 months compared to 49.37 kg/tree at 10 months in young trees. N concentration pattern differed from the biomass, as %N were significantly lower (P < 0.05) as pruning delayed in both age groups. At 4 months, young trees had 57 kg N ha−1 compared to 64 kg N ha−1 at 8 months in old trees. In conclusion, pruning regimes in gliricidia should be guided by the age of the trees. Hence, it would be theoretically enough to prune young trees at 4 months and old trees at 8 months to meet the N need (58–80 kg ha−1) of cocoa to diminish external N-fertilizer needs.

Early cultivation and bioturbation cause high long-term soil erosion rates in tropical forests: OSL based evidence from Ghana

Soil erosion in forests is often considered negligible or minimal. In some tropical forest ecosystems, however, the combination of continuous surface exposure of fine soil particles at the upper slope by soil macrofauna and episodic precipitation can cause considerable downslope soil transport, and the introduction of slash and burn agriculture is often found to speed up soil erosion even more. Here we, for the first time, use OSL dating to quantify the long-term soil erosion rate along a hillslope in the moist semi-deciduous forest zone of Ghana. During the last ~4–5000years about 100cm of sediment has accumulated at an approximately constant rate of ~0.13–0.21mmyear−1 (1.95–3.15tha−1year−1). This is about an order of magnitude higher than literature estimates from similar environments, primarily obtained using short-term experimental setups; this suggests that care should be taken when extrapolating short-term erosion estimates to centennial or millennial timescales. We further deduce that an apparent acceleration in erosion began ~4500years ago. This may be due to the introduction of cultivation in the area, slightly earlier than previously suggested (2800–3500years ago). In this case the erosion rate based on deposition below 100cm (~0.05mmyear−1) can be taken to represent the (natural) erosion rate without human influence; this value is consistent with literature estimates. More retrospective studies of soil erosion rates are needed in order to confirm the validity of our methodology and results, as well as to test the reliability of extrapolated short-term erosion estimates.

Determination of dust deposition and associated nutrients in natural forest and plantation - A case study from the moist semi-deciduous forest zone in Ghana

Every year in December to February the dust laden Harmattan blows from Sahara towards southwest to the countries along the east west going coast of the Gulf of Guinea. Only few investigations have quantified external dust deposition in forests and plantations in that region and hereby the nutrient input by dust. This paper investigates three different methods for sampling and quantifying dust deposition in natural forests and plantations in the moist semi-deciduous forest zone in Ghana. The three methods tested were the following: bowls with water, plastic mats with straws and funnels for determining canopy drip. The study shows that the canopy drip method overestimates the external dust deposition due to a significant enrichment of organic matter during the throughfall. Therefore, it is necessary to combine the canopy drip method with sampling from outside the forest to determine the external organic matter content in the dust deposited to a forest. The study showed that the dust deposition in the forest and in the rubber and cocoa plantations was 1.5 to 2.0 times bigger than on the plastic mats located outside the forested area and further, that the external nutrient input by dust to the natural forests is very low in the Kade area, only about 0.2 kg ha-1 total P and the readily available Ca, Mg and K are respectively 0.4 kg ha-1, 0.2 kg ha-1 and 0.7 kg ha-1.

Blood-Feeding Behavior of &lt;I&gt;Anopheles gambiae&lt;/I&gt; and &lt;I&gt;Anopheles melas&lt;/I&gt; in Ghana, Western Africa

Anopheles gambiae is the predominant malaria vector species in Ghana, western Africa, with a strong local presence of Anopheles melas Theobald along the southern coast. We studied the biting behavior of these two species of the Anopheles gambiae complex inland and at the coast in Ghana, with special attention to the local peoples' preference for outdoor sleeping. We collected mosquitoes at two sites in 2007, representing the moist semideciduous forest zone and the strand and mangrove zone, and the sampling was repeated in the dry and rainy seasons. Sampled mosquitoes were examined for species, parity and size (wing length), and we identified the hosts of their bloodmeals. We interviewed 288 of the village people to determine where and when they slept outdoors. Our study confirmed that An. gambiae is the only species of the An. gambiae complex in the Ashanti region and revealed that An. melas is highly dominant on the western coast of Ghana. Both species showed high human blood rates in indoor resting mosquito samples. More people sleep outside on the coast than inland. An. melas demonstrated high exophily. An. gambiae bit people more frequently indoors and did so more often during the dry season than in the rainy season. We suggest that the degree of exophily in An. melas may be affected by humidity and the availability of human as well as by the mosquitoes' innate habits.

The Flora and mammals of the moist semi-deciduous Forest Zone in the Sefwi-Wiawso District of the Western Region, Ghana

The study presents results of a floristic and mammal survey undertaken in the Sefwi-Wiawso District within moist semi-deciduous vegetation zone of the Western Region of Ghana. The floral survey involved estimating the floral distribution, abundance and diversity using the standard indices, Shannon-Wiener, Simpson’s, evenness, species richness, similarity, and â-diversity, while the mammal survey was conducted using direct opportunistic observation, live-trapping (small mammals), animal spoors/trophies, and interviews. There were 271 plant species recorded, out of which 174 species comprising 172 species and 67 families of angiosperms (Angiospermae) and two species of ferns (Pterydophyta) were scientifically-named. Forty species of mammals representing eight orders were recorded, with the dominant orders being Rodentia and Artiodactyla. The greatest faunal diversity occurred in the forest reserves, where suitable habitat niches still occur. There were 48 individuals of seven species of rodents and one individual of one insectivore species captured during live-trapping, with the commonest species being common mice (Mus spp.) and brush-furred mice (Lophuromys flavopunctatus). The greatest threat to the survival of the fauna is habitat destruction. Generally, the Sefwi-Wiawso District is very rich in forest tree species, the commonest being the Celtis-Triplochiton Associations, but bad agricultural practices, bush burning, intense logging, fuelwood harvesting and pollution have resulted in poor soil quality and land degradation in certain areas. Hunting of animals for meat, and destruction of habitats were the greatest threats to faunal diversity and abundance in the Sefwi-Wiawso District.

Soil properties of a toposequence in the moist semi-deciduous forest zone of Ghana

Soil properties of a toposequence in the moist semi-deciduous forest zone of Ghana

Relative susceptibility of four species of African mahogany to the shoot borer Hypsipyla robusta (Lepidoptera: Pyralidae) in the moist semideciduous forest of Ghana

We examined the relative susceptibility of four mahogany species, Khaya ivorensis, Khaya anthotheca, Entandrophragma angolense, and E. utile, to Hypsipyla robusta attack. Seeds were obtained from one to three parent trees for each species. The research was conducted in the moist semideciduous forest zone in Ghana and used a randomized complete block design. Tree height and diameter and height to first branch were measured until 24 months after out-planting in the field. H. robusta damage was assessed by counting the numbers of shoots attacked, branches, and dead shoots. Khaya spp. grew better but experienced more attack than Entandrophragma spp. The relative susceptibility to H. robusta attack, from most to least, of the four species was: K. anthotheca > K. ivorensis > E. angolense > E. utile. At 24 months, the mean number of shoots attacked per tree ranged from 1.0 for an E. utile seed source to 3.6 on for a K. anthotheca seed source. At 15 months, K. anthotheca and K. ivorensis started branching at about 1.5 m, but height of clear trunk increased over time due to self-pruning. As K. anthotheca grew taller, the number of H. robusta attacks per tree declined. This suggested that selection of genotypes and species that are tolerant of H. robusta attack based on infestation of young plants may not be appropriate. Genetic factors more completely reflecting the response of different species and genotypes to H. robusta attack may manifest themselves at later growth stages.

Soil sampling size estimates for soils under teak (Tectona grandis Linn. F) plantations and natural forests in Ashanti Region, Ghana

The variability of forest soil properties and the number of samples required to achieve desired levels of precision for estimation of property means have received little attention in the tropics. Highly variable forest soil properties require more intensive sampling and often have less predictive value for site assessment purposes. Sites at Offinso and Juaso Forest Districts in the Ashanti region, Ghana, were used to study the variability patterns for selected physical and chemical properties. Sites selected for this study were in the moist semi-deciduous forest zone and had nearly identical physiographic characteristics. A simple random sampling procedure was used to obtain soil samples at each site. In each of three natural forest stands and three teak plantations, 16 soil pits were examined and soil samples from the 0- to 20-cm (major rooting depth) and 20- to 40-cm depths were analyzed for selected chemical and physical properties. In the 0- to 20-cm depth, coefficients of variation varied from 8% (pH) to 72% (available P), and in the 20- to 40 cm depth from 16% (pH) to 116% (available P) under teak plantations. Similarly, in the 0- to 20-cm depth coefficients of variation varied from 11% (pH) to 40% (exchangeable K) and in the 20- to 40-cm depth from 10% (bulk density) to 86% (available P) under natural forests. Under both cover types, more samples were required to estimate means at ±10% allowable error with a confidence level of 95% for chemical properties than for physical properties. Key words: Tectona grandis plantations, moist semi-deciduous forest zone, Ghana, soil physico-chemical properties, forest ochrosol

Studies on a Wood-Feeding Termite Community in Ghana, West Africa

Following the partial clearance of farm scrub some termite species became locally extinct or scarcer, some were not affected, whilst others were adversely affected but became re-established and increased their activity. Wood-feeding termites in the moist semi-deciduous forest zone of Ghana consume about 0.2 kg m-2 yr-1 of woody material. This weight accounts for about 20 percent of the litter fall or about 8 to 10 percent of the annual primary production of the deciduous forest and a rather greater proportion of the lower production of more open sites. There is a spatial heterogeneity in the species distribution. Although water, clay, silt and sand contents of soil, and temperature, sunshine, and sunflecks were measured, the only significant correlations are of these parameters with Microtermes subhyalinus, which is more frequent in the moister areas with higher silt and lower sand content, and also shows a temperature preference. The lack of significance in correlation and principal component analyses is attributed to the observations being made away from the unknown location of the underground nest, and the ability of termites partially to modify their environment. The several coexisting wood-feeding species show slight micro-environment preferences leading to some spatial separation, and also show a series of size differences. The species show different responses to potential food resources, some apparently preferentially attacking wood in which fungal decomposition has begun and others not. TERMITES (Isoptera) are an important component of the fauna of tropical soils. Their efficiency in utilizing many food sources has meant that some species have become pests of crops or timber, and a few species have attacked a great variety of manmade materials. Because of their economic importance, the majority of studies of tropical termites have concentrated on the pest species and their control. The species known to attack crops have been reviewed by Harris (1961, 1969), whilst Sands (1960) has reviewed the species destroying timber and crops in West Africa. Further, Harris (1970) has listed all the species known to attack structural timbers, whilst Small et al. (1960) have described the effect of termites upon West African timbers. There have been relatively few studies on the populations of tropical termites. The relations between termites and soil have been reviewed by Lee and Wood (1971), though much of their detailed work was undertaken in Australia where the Macrotermitinae, the termites with perhaps the greatest population density in Africa, are absent. A general review of African termites is given by Bouillon (1970). Sands (1965b) attempted to sample subterranean termite populations during studies on the effect of human interference with vegetation communities in the West African savanna. However, later Sands (1972) drew attention to the extreme difficulty of obtaining estimates of the population density of truly subterranean, as opposed to moundbuilding, termite species. The work described here gives an indirect estimate of the population size and impact of a woodfeeding termite community, the majority of whose members are subterranean. These studies were undertaken during the development of a termite test site, mainly designed for conducting 'graveyard'-type tests. The Ghanaian Council for Scientific and Industrial Research wished the site to be developcd in an area of farm scrub near the village of Fumesua, about 10 km east of Kumasi (6?40'N, 1?35'W), in the Ashanti Region of Ghana. Since no previous work has been undertaken on the termite fauna of the area, the present study was designed to cover the first year of the creation of the test site, prior to any tests being carried out. It was thought important to know the ecological characteristics of the termites potentially able to attack the test samples, and the community structure of the termites that might be killed by chemical treatments of soil or wood.