Miombo Research Articles

Standing fuel with back‐fires are effective in reducing fire hazardous in prescribed burning in the deciduous miombo woodland

AbstractSavannah fires are of utmost importance to the livelihoods of rural households living in the miombo woodlands of southeast and southern Africa in carrying out their daily activities. In order to add to the existing knowledge on safe prescribed burning procedures, we developed an experimental physics‐based approach modelled on the implementation of a winter surface fire in northern Mozambique. Twelve experimental fire plots were established and burned to identify local conditions that allow a safe prescribed burn to be conducted in the Miombo woodland, northern Mozambique. Two non‐destructive methods were used to measure the amount of forest fuel, namely: the disk meter method and the triangular line‐intercept sample. The plots were burned alternately and parallel to the prevailing wind direction using a head and backing fire. Relationships between fire behaviour, fuel properties, site characteristics and weather conditions were determined using Analysis of Variance (ANOVA) and Covariance (ANCOVA). The ANOVA models predicted 51% and 55% of fire behaviour variance for the flame height and rate of spread, respectively, while the ANCOVA accounted for 67% and 65% of fire behaviour for the flame height and rate of spread, respectively. Findings from this research suggest that standing fuel with back‐fire produces lower‐intense fire with higher controllability.

The impact of bushfires on animal abundance and diversity across land tenures in Miombo woodlands, Tanzania

Abstract. Matimbwi L, Madoffe SS. 2022. The impact of bushfires on animal abundance and diversity across land tenures in Miombo woodlands, Tanzania. Asian J For 6: 43-51. Southern Africa is dominated by Miombo forests (woodlands), the world's largest savanna. The purpose of this research was to examine how bushfires affect mammalian populations in Miombo woodlands under various forest tenure systems. The data was gathered through household questionnaires, a probing question checklist for key informants, participant observation, Participatory Rural Appraisal (PRA) methods, and a field inventory. We enlisted the aid of the local communities in our analysis of the PRA data we collected. Quantitative and qualitative data and information were subjected to content and structural-functional analysis. Quantitative data was examined using Statistical Package for the Social Sciences (SPSS) software. Microsoft Excel was used to examine inventory data on animal stocks. The average number of mammals collected from each forest tenure system was compared using Analysis of Variance (ANOVA) to see if there were statistically significant variations. The variety of mammal species in various forest tenure systems was measured using the Shannon-Wiener Index (H). Based on the findings, agricultural activities (44.5%), charcoal production (21.1%), and wildlife hunting (18.9%) accounted for the vast majority of bushfires in Miombo woods. It was thought that illegal logging and honey collection were the only contributing factors. Mammal populations tend to be most significant in Central Governmental Forest Reserves, then in those of the Local Government, and finally in those of the Village Government. Mildly burned sections in the Central Governmental Forest Reserve had a diversity index of 3.2. In contrast, those in the Local Government Forest Reserve and the Village Forest Reserve had indices of 2.0. There was little difference in the diversity index values of the Central Governmental Forest Reserve (2.0) and the Village Forest Reserve (2.0) for moderately burned blocks and the Local Government Forest Reserve (1.6) for unburned blocks. The Central Governmental Forest Reserve had a diversity value of 1.5 for the severely burned blocks, the Village Governmental Forest Reserve had a value of 1.4, and the Local Government Forest Reserve had a value of 1.2. Like other mammals with a low fire escape rate, bushfires hit the rock hyrax particularly hard. As a result, it is suggested that the current management regimes of Local Government Authorities be strengthened to ensure enhanced local community participation with more effective law enforcement measures to save the woods from deterioration. Similarly, communities should be given access to financing and encouragement to pursue income-generating activities to lessen their reliance on Miombo woodlands.

Tree Species Composition and Diversity in Fire-Affected Areas of Miombo Woodlands, Central Mozambique

Fire strongly impacts the composition and structure of ecosystems, with consequences yet to be understood. We used Moderate Resolution Imaging Spectroradiometer (MODIS) data to map fire frequency and fire intensity and investigate their effects on miombo woodlands (MW) of central Mozambique. Tree species diversity was evaluated and compared using rarefaction curves. Non-metric multidimensional scaling (NMDS) ordination was used to identify patterns of species composition occurrence. The indicator value index method was applied to verify the occurrence of fire indicator species. In general, tree communities responded differently to varied fire regimes. We found low tree density in Intermediate fire frequency and intensity (IfIi) (180 trees ha−1) and High-frequency and Low intensity (HfLi) (316 trees ha−1) areas. The IfIi fire regime had the lowest carbon stocks (9.1 Mg ha−1), when compared to the rest of fire regimes. The species diversity decreased as fire intensity increased. IfIi areas had the maximum species diversity. The NMDS showed a varied species composition according to fire regime. We found a strong relationship between the species diversity and composition, and the pattern of fire occurrence in each fire regime. Our results are critical in supporting fire management policies and understanding fire regimes and their effects on miombo trees’ structure and composition.

DYNAMICS OF THE FOREST LANDSCAPE IN THE MIKEMBO SANCTUARY: 20 YEARS AFTER ITS CREATION AS A FLORA AND FAUNA CONSERVATION RESERVE, UPPER-KATANGA, DR CONGO

Remote sensing is very important for conservation and biodiversity research and applications. For instance, it can be used for monitoring changes in ecosystems. Objective: The objective of this paper was to analyze the change in the forest landscape of Mikembo Sanctuary between 2002 and 2022 using satellite imagery. Method: Supervised classification by maximum likelihood algorithm was performed and helped to differentiate 3 land use classes. Results: The cartographic and statistical analysis show that land use dynamics of the study area are dominated by an increase in forest and a reduction in bare soil. The forest increases with 0.78 km2 (18.04% of the study area) and therefore had a rate of change of more than 32.25%. Conclusion: It has been demonstrated that the Miombo woodland, specially Mikembo Sanctuary is capable of regenerating naturally or by assisted means. Encouraging people for using alternative solutions is necessary to ensure the sustainable forest management and utilization.

The size of clearings for charcoal production in miombo woodlands affects soil hydrological properties and soil organic carbon

Charcoal production is a major driver of forest degradation in miombo woodlands. Forests play a crucial role in regulating the hydrological cycle, so it is critical to understand how forest degradation and management practices impact water availability, particularly in drylands. Few studies have examined the effect of forest clearing size on the hydrological functioning of soil, particularly under real-world conditions where, following clearing, forests are subject to multiple and prolonged anthropogenic disturbances, as occurs in miombo woodlands which are cleared for charcoal production and commonly used for livestock grazing. The pilot project Transforming Tanzania's Charcoal Sector was established in 2012 with the aim of establishing a sustainable wood harvesting system for charcoal production based on rotational harvesting cycles that allow for natural forest regeneration. Two clearing sizes were established: large clearings (300 × 300 m) harvested by clear-felling, and small clearings (50 × 50 m) harvested in a checkerboard pattern. We examined the effect of these two clearing sizes on soil hydrological properties and soil organic carbon (SOC) in Kilosa district, Morogoro, Tanzania. Our analysis included four treatments: large clearings, small clearings, small intact plots (unharvested plots within the checkboard pattern), and village land forest reserve. For each treatment we assessed the tree cover and measured soil infiltration capacity, soil bulk density, SOC stock, and texture. We also examined the relationship between these variables and the distance to the closest road to better understand the impact of livestock and human disturbance. Our results show that large clearings had the lowest mean infiltration capacity (121 ± 3 mm h−1) and SOC stock content (12 ± 0.2 tonnes ha−1), and the highest bulk density (1.6 ± 0.005 g cm−3) of all the treatments. We found a positive relationship between infiltration capacity and basal area (R2 = 0.71) across all treatments. We also found that infiltration capacity, SOC stock and tree basal area increased with increasing distance from the closest road, while bulk density decreased. We conclude that, in terms of their impact on soil hydrological functioning and SOC stock, small clearings, while not completely unaffected, are better than larger ones. In small clearings, concurrent reductions in tree cover and a relatively low impact on soil hydrological properties could result in increased soil and groundwater recharge compared to unharvested forest areas. Controlling livestock grazing can further minimize soil degradation, producing additional gains.

Fire regime of peatlands in the Angolan Highlands.

The Angolan Highlands region includes the Angolan miombo woodland ecoregion which supports miombo woodland, grasslands, subsistence agricultural land, and peatland deposits. Extensive fires, slash and burn agriculture, peat fuel extraction, and peatland drainage are among the anthropogenic practices that threaten these peatland deposits. Peat fires cause peatland degradation, release significant amounts of greenhouse gases, deteriorate air quality, and contribute towards climate change and biodiversity loss. This study presents an analysis of the fire regimes over the period 2001 to 2020 in an under-studied area of the Angolan Highlands. Moderate Resolution Imaging Spectroradiometer (MODIS) fire and vegetation data were used in combination with a land use/land cover (LULC) classification map to calculate fire frequency, burn area, and fire regimes. The fire patterns within the study site are comparable to those found in African woodland savannas. Across the study site, 6976 km2 (11.31%) of the land surface area burned at least nine times from 2001 to 2020, occurring largely within in the river valley environment. Considering the different LULC classes, peatlands were calculated to (a) burn more frequently (average fire frequency from 2001 to 2020 = 9.12), (b) have the smallest proportion (4.11%) of area which remained unburnt over the fire archive, and (c) have the largest average proportion (45.65% or 746 km2) of burnt area per year. Peatland burning occurred predominantly during drier months from May to September. The results of this study highlight the strong influence of LULC on the fire frequency and distribution in the study area, requiring unique fire management strategies. As has been documented for boreal and tropical peatlands across the globe, we stress the importance of peatland conservation and protection; continued unsustainable management practices may lead to the loss of these important peatland deposits.

Linking Bacterial Rhizosphere Communities of Two Pioneer Species, Brachystegia boehmii and B. spiciformis, to the Ecological Processes of Miombo Woodlands

Miombo is the most extensive ecosystem in southern Africa, being strongly driven by fire, climate, herbivory, and human activity. Soils are major regulating and supporting services, sequestering nearly 50% of the overall carbon and comprising a set of yet unexploited functions. In this study, we used next-generation Illumina sequencing to assess the patterns of bacterial soil diversity in two pioneer Miombo species, Brachystegia boehmii and Brachystegia spiciformis, along a fire gradient, in ferric lixisol and cambic arenosol soils. In total, 21 phyla, 51 classes, 98 orders, 193 families, and 520 genera were found, revealing a considerably high and multifunctional diversity with a strong potential for the production of bioactive compounds and nutrient mobilization. Four abundant genera characterized the core microbiome among plant species, type of soils, or fire regime: Streptomyces, Gaiella, Chthoniobacter, and Bacillus. Nevertheless, bacterial networks revealed a higher potential for mutualistic interactions and transmission of chemical signals among phylotypes from low fire frequency sites than those from high fire frequency sites. Ecological networks also revealed the negative effects of frequent fires on the complexity of microbial communities. Functional predictions revealed the core “house-keeping” metabolisms contributing to the high bacterial diversity found, suggesting its importance to the functionality of this ecosystem.

Trees in agricultural landscapes maintain soil organic carbon following miombo woodland conversion to shifting cultivation

The main driver of deforestation and degradation of miombo woodland is shifting cultivation (SC). SC is the main farm system and livelihood of the people in miombo woodlands. Assessing the current body of knowledge, the following apparent gaps were identified: (i) researches analysing the response of soil-C to woodland (miombo) conversion to SC are contradictory; (ii) studies reporting all the stages of agriculture-induced ecological succession (woodland, shifting cultivation, fallow vegetation, and reconversion to shifting cultivation or to woodland) are lacking. The response of soil-C to (1) dry miombo woodland (DM) conversion to SC, (2) SC conversion to fallow vegetation, (3) reconversion of fallow vegetation to SC, (4) the length of the cropping and fallowing periods, and (5) land-use intensification, was studied. The study was carried out in a landscape mosaic consisting of treeless SC, tree-based SC, grass fallow (treeless SC-fallow), and woody fallow (tree-based SC-fallow). DM conversion to treeless SC resulted in depleted soil-C by up to 72%; the depletion increased with the increasing length of the cultivation period. The fallow period (grass fallow) recovered part of the soil-C lost during the cultivation period: grass fallow lands were approximately threefold larger in soil-C stocks than treeless SC lands. Soil-C increased with increasing grass fallow age. No significant changes in soil-C were observed when DM was converted to tree-based SC, or when tree-based SC lands were left under fallow (woody fallow); consequently, soil-C did not vary with the increasing lengths of cultivation and fallow periods. Woody fallows were up to 45% higher in soil-C stocks than grass fallows. Reconversion of grass fallow to treeless SC resulted in soil-C loss; no changes were observed when woody fallows were reconverted to tree-based SC. Land-use intensification by increasing the frequency of SC cycles did not alter soil-C in either treeless or tree-based SC. It was concluded that, under the study area conditions, the response of soil-C to agriculture-induced land-use changes depends mainly on the presence or absence of the arboreal component. Maintaining or introducing the arboreal component is recommended to avoid or mitigate soil-C loss following DM conversion to SC.

The Application of UASs in Forest Management and Monitoring: Challenges and Opportunities for Use in the Miombo Woodland

The Miombo woodland is the most extensive tropical woodland in south-central Africa. However, field sample plot data on forest cover changes, species distribution and carbon stocks in the Miombo ecoregion are inadequate for effective forest management. Owing to logistical challenges that come with field-based inventory methods, remote sensing plays an important role in supplementing field methods to fill in data gaps. Traditional satellite and manned aircraft remote sensing platforms have their own advantages and limitations. The advent of unmanned aerial systems (UASs) has made it possible to acquire forest data at unprecedented spatial and temporal scales. UASs are adaptable to various forest applications in terms of providing flexibility in data acquisition with different sensors (RGB, multispectral, hyperspectral, thermal and light detection and ranging (lidar)) at a convenient time. To highlight possible applications in the Miombo woodlands, we first provide an overview of the Miombo woodlands and recent progress in remote sensing with small UASs. An overview of some potential forest applications was undertaken to identify key prospects and challenges for UAS applications in the Miombo region, which will provide expertise and guidance upon which future applications in the Miombo woodlands should be based. While much of the potential of using UASs for forest data acquisition in the Miombo woodlands remains to be realized, it is likely that the next few years will see such systems being used to provide data for an ever-increasing range of forest applications.

Spatio-temporal changes in chimpanzee density and abundance in the Greater Mahale Ecosystem, Tanzania.

Species conservation and management require reliable information about animal distribution and population size. Better management actions within a species' range can be achieved by identifying the location and timing of population changes. In the Greater Mahale Ecosystem (GME), western Tanzania, deforestation due to the expansion of human settlements and agriculture, annual burning, and logging are known threats to wildlife. For one of the most charismatic species, the endangered eastern chimpanzee (Pan troglodytes schweinfurthii), approximately 75% of the individuals are distributed outside national park boundaries, requiring monitoring and protection efforts over a vast landscape of various protection statuses. These efforts are especially challenging when we lack data on trends in density and population size. To predict spatio-temporal chimpanzee density and abundance across the GME, we used density surface modeling, fitting a generalized additive model to a 10-year time-series data set of nest counts based on line-transect surveys. The chimpanzee population declined at an annual rate of 2.41%, including declines of 1.72% in riparian forests (from this point forward, forests), 2.05% in miombo woodlands (from this point forward, woodlands) and 3.45% in nonforests. These population declines were accompanied by ecosystem-wide declines in vegetation types of 1.36% and 0.32% per year for forests and woodlands, respectively; we estimated an annual increase of 1.35% for nonforests. Our model predicted the highest chimpanzee density in forests (0.86 chimpanzees/km2 , 95% confidence intervals (CIs) 0.60-1.23; as of 2020), followed by woodlands (0.19, 95% CI 0.12-0.30) and nonforests (0.18, 95% CI 0.10-1.33). Although forests represent only 6% of the landscape, they support nearly one-quarter of the chimpanzee population (769 chimpanzees, 95% CI 536-1103). Woodlands dominate the landscape (71%) and therefore support more than a half of the chimpanzee population (2294; 95% CI 1420-3707). The remaining quarter of the landscape is represented by nonforests and supports another quarter of the chimpanzee population (750; 95% CI 408-1381). Given the pressures on the remaining suitable habitat in Tanzania, and the need of chimpanzees to access both forest and woodland vegetation to survive, we urge future management actions to increase resources and expand the efforts to protect critical forest and woodland habitat and promote strategies and policies that more effectively prevent irreversible losses. We suggest that regular monitoring programs implement a systematic random design to effectively inform and allocate conservation actions and facilitate interannual comparisons for trend monitoring, measuring conservation success, and guiding adaptive management.

Calling for landscape-level assessments of participatory forestry's role in improving forest biophysical conditions

Participatory forest management (PFM) has been applied to address declining tropical forest conditions. In the literature, there is a mixed evidence on PFM's role in improving forest conditions. However, most assessments ignore a relationship between household distance from PFM forests and impacts to non-PFM forests albeit being an essential aspect. Some PFM assessments show that distance matters in determining an individual's participation But, sparsely discussing the distance in relation to forest biophysical conditions in a landscape context. Drawing on the landscape approach and insights from Miombo forests of Kilwa in southern Tanzania, we illustrate the importance of studying PFM schemes in a landscape context to illuminate the relationship between household distance from PFM forests and impacts to non-PFM forests. Our study villages have forest abundances in areas between households and PFM forests. The average distance between households and PFM forests is 7.8 km. The long distances and forest abundances produce an ‘outbound effect’, whereby degrading and deforesting activities shift from PFM to non-PFM forests. Our analysis calls for landscape-level assessments that include forests under different governance regimes even those in unreserved landscapes – non-PFM forests. This is important for two reasons. First, for generating locally grounded contextual insights necessary for developing understandings of global forest conservation efforts from the ‘ground up’. Second, for revealing correct forest conditions in the entire landscape critical in the light of ongoing national and international interests to manage trees inside and outside designated forest reserves for both carbon sequestration and landscape restoration.

Nuclear ribosomal phylogeny of Brachystegia: new markers for new insights about rain forests and Miombo woodlands evolution

Background and aims – Brachystegia is a species-rich tree genus found in tropical Africa and a typical element of Miombo woodlands, a widely distributed subtype of the Zambezian savanna. Plastid DNA was shown to be largely uninformative to assess species phylogenetic relationships due to widespread chloroplast capture among species. Here, we aim to assess the capacity of nuclear ribosomal DNA (rDNA) to clarify the phylogeny of Brachystegia species while accounting for intra-individual site polymorphisms (2ISPs), which are often present in rDNA and potentially phylogenetically informative. Material and methods – Genome skimming sequencing on 47 samples representing 27 of the 29 currently recognized Brachystegia species, allowed us to retrieve complete nuclear ribosomal cistrons encoding for 18S, 5.8S, and 25S rRNA genes (35S rDNA). We reconstructed the Brachystegia phylogeny using Maximum Likelihood methods based on the standard substitution model or integrating 2ISPs (GENOTYPE implementation in RAxML-NG). We additionally tested the effect of partitioning the data (one partition for rDNA genes and one for the ITS1+ITS2). We also conducted network inferences (Neighbor-Net splits graph), as a strict bifurcative approach might not properly model topological uncertainty at shallow phylogenetic depth. Key results – 2ISPs-aware and standard phylogenetic reconstructions are largely congruent. We identified several well-supported main clades clarifying the species relationships, including two clades of Miombo woodlands species. Miombo Group A includes species with ovoid to globose axillary dormant buds, while Miombo Group B species have flattened ones. Two morphologically close Brachystegia species (B. kennedyi and B. leonensis) found in Guineo-Congolian rain forests form also a robustly supported clade. 2ISPs coding allowed to identify an additional Guineo-Congolian clade (B. eurycoma and B. nigerica). Ribosomal DNA therefore proves more useful to explore the generic phylogeny than plastid DNA but the species relationships within and among the main clades remain poorly resolved, probably due to recent diversification and/or recurrent hybridization, so that the diversification of Brachystegia remains to be more properly characterised. Conclusion – Nuclear and plastid phylogenetic reconstructions of Brachystegia species are discordant. Even if not well-resolved, rDNA phylograms and networks are characterized by taxonomic sorting, while we observe a strictly geographic sorting in the plastid dataset. Most of the species’ relationships remain to be characterized using additional nuclear markers combined with in-depth morphological investigations.

Hunter-gatherer environments at the Late Pleistocene sites of Mwanganda's Village and Bruce, northern Malawi

Mwanganda's Village (MGD) and Bruce (BRU) are two open-air site complexes in northern Malawi with deposits dating to between 15 and 58 thousand years ago (ka) and containing Middle Stone Age (MSA) lithic assemblages. The sites have been known since 1966 and 1965, respectively, but lacked chronometric and site formation data necessary for their interpretation. The area hosts a rich stone artifact record, eroding from and found within alluvial fan deposits exhibiting poor preservation of organic materials. Although this generally limits opportunities for site-based environmental reconstructions, MGD and BRU are located at the distal margins of the alluvial fan, where lacustrine lagoonal deposits were overprinted by a calcrete paleosol. This has created locally improved organic preservation and allowed us to obtain ecological data from pollen, phytoliths, and pedogenic carbonates, producing a regional- to site-scale environmental context for periods of site use and abandonment. Here, we integrate the ecological data into a detailed site formation history, based on field observations and micromorphology, supplemented by cathodoluminescence microscopy and μ-XRF. By comparing local, on-site environmental proxies with more regional indicators, we can better evaluate how MSA hunter-gatherers made decisions about the use of resources across the landscape. Our data indicate that while tree cover similar to modern miombo woodland and evergreen gallery forest prevailed at most times, MSA hunter-gatherers chose more locally open environments for activities that resulted in a lithic artifact record at multiple locations between 51 and 15 ka.

English

Habitat type and their vegetation composition play important role in determining the abundance and diversity of animals including small mammals, hence any change in habitat type will influence their abundance and spatial distribution. This study aimed at investigating the influence of habitat types (that is, Wetland grassland, Miombo and Vachellia woodlands) on small mammal abundance, diversity, and richness in the Usangu area, in southern part of Ruaha National Park, in Tanzania. Sherman and pitfall plastic bucket traps were employed both for trapping small mammals. A total of  92 small mammals were captured in 2124 trap nights giving 13% trap success representing two families, namely, Muridae (6 species) and Soricidae (1 species). Furthermore, trap success differed among habitat types with the highest being in wetland grassland. Species diversity was higher in Vachellia woodlands compared to other habitat types. It would therefore seem that wetland grassland and Vachellia woodland habitats are very crucial in maintaining small mammal abundance and diversity in Usangu Area. Therefore, future management plan should incorporate these refuge habitats for continued existence of small mammals in Usangu. Further study is warranted in wet season in order to have comparison information that will assist in management of small mammal in Usangu.    Key words:  Conservation, habitat preferences, habitat restoration, Miombo woodlands, rodents, Ruaha National Park, Tanzania, Vachellia woodlands, wetland grassland.

An analysis of the recent fire regimes in the Angolan catchment of the Okavango Delta, Central Africa

BackgroundThis paper presents an analysis of fire regimes in the poorly studied Angolan catchment of the Okavango Delta in Botswana. We used MODIS data to examine the frequency and seasonality of fires over 20 years (from 2000 to 2020) in three dominant vegetation types (miombo woodlands, open woodlands and grasslands, and short closed to open bushlands), and in areas where people were present, and where they were absent.ResultsThe median fire return intervals for both open woodlands and grasslands and short bushlands were relatively short (1.9 and 2.2 years respectively). In miombo woodlands, fires were less frequent (median return periods of 4.5 years). Human population density had no discernible effect on the fire return intervals, but about 14% of the miombo woodlands experienced no fires over 20 years. Ongoing shifting cultivation within miombo woodlands has led to structural changes and the introduction of fire into this vegetation type where fires were rare or absent in the past. About 12% of the miombo did not burn during the period examined where people were present, whereas close to 20% of the sites remained unburnt where people were absent. This suggests that people did not change the fire return interval in any of the vegetation types studied, but that they altered the amount of the landscape that is flammable in miombo vegetation. Fires occurred between June and September, with a peak in the late dry season (August and September).ConclusionsHistorical research indicates that late dry-season fires are detrimental to miombo woodlands, and our analysis suggests that degradation in parts of the catchment has led to the introduction of fire to this previously fire-free and fire-sensitive vegetation type. Deforestation of miombo woodlands, and the consequent introduction of fire, is a cause for concern with respect to the ecological stability of the Okavango Delta. Managers should therefore aim to protect the remaining closed-canopy miombo stands from further clearing and to attempt to shift the timing of burns to the early dry season to reduce their intensity.

Effect of Organic Amendment on the Physicochemical Characteristics of Tailings Dam Soil and Root Development of Tree Species, Fifteen Years After Planting

Among mine wastes, tailings are known to have the largest environmental impact, as they have high concentrations of trace elements and are susceptible to wind dispersal and water erosion. A tree plantation trial was installed at Kipushi tailing (DR Congo) in order to mitigate the contaminant dispersal in the surrounding areas. Fifteen years later, the present study was conducted for the purpose of investigating the macronutrient and metal content in amended holes and assessing the performance of tree species through root behavior in the tailings dams. Results show elevated available P, K, Ca, and Mg concentration in the surface and amended layers, which is higher than the unpolluted soil of the miombo woodland. Trace metals were manifold higher compared to the pedo-geochemical background of the region, with Cu and Co concentration tending to increase in the organic matter-rich layers, while Zn, Cd, Pb, and As remained higher in tailings. Compared to the tailing layer, roots grew well in the amended layers, but few roots ranging from very fine to big from all the surviving species were able to grow beyond the amended layers, indicating the possibility of tree survival on the tailings dams over many years. Acacia polyacantha and Psidium guajava are species that showed a higher quantity of roots in the unamended tailing layers. Leaves should be avoided for human or animal consumption, but as the concentration of Cu, Zn, and Co in guava was lower, there is no indication of hazards in case of their consumption. Therefore, the use of well-adapted tree species on the mix-up of the organic amendments with the uncontaminated topsoil seemed to be a good technique for the reclamation of larger polluted areas.

Influence of Charcoal Production on Forest Degradation in Zambia: A Remote Sensing Perspective

A multitemporal dataset of medium-resolution imagery was used to document a tree cover loss process in three forest reserves of Zambia. This degradation process was attributed to charcoal production with a high degree of certainty, as evidence of kiln scars was found in more than 85% of sites sampled with high-resolution imagery across the study areas. The spatial and temporal pattern of mapped kiln scars exposed an intense and fast-paced degradation process, with kiln densities reaching 2.3 kiln/ha, removal of about 79.3% of the aboveground biomass and reductions of 74.2% of tree cover. The analysis revealed that this forest degradation process progressively moves further away from urban centers. In the year 2010, charcoal production took place around 190 km away from Lusaka, whereas extraction areas in 2020 were located around 350 km from this city. These results underline the negative impact of charcoal production on forest resources and question its characterization as localized and periurban. The post-disturbance LCLUC trajectories of degraded woodlands in forest reserves revealed a partial conversion to agricultural land over time, with less than 25% of these woodlands cultivated seven years after charcoal production. The disaggregation of the supply sources of charcoal for the city of Lusaka based on consumption figures and remote sensing deforestation records showed that the charcoal generated as a byproduct of agricultural expansion is not enough to meet the annual charcoal demand of Lusaka. On the contrary, the majority (65%) of this charcoal is the result of a forest degradation process that alters 197.4 km2 of miombo woodlands annually. These findings highlight the role of charcoal production as a direct driver of forest degradation and suggest that forest degradation resulting from charcoal production has surpassed deforestation due to agricultural expansion as the main tree cover loss process in Zambia. These results provide data-driven evidence to improve the characterization of forest degradation resulting from charcoal production across the woodlands of southern Africa and aid the REDD + monitoring, reporting and verification systems in compliance with international reporting commitments.

Indigenous knowledge on wild mushrooms in communities bordering miombo woodlands of central Zimbabwe

ABSTRACT Apart from timber, fruits, honey, firewood and other benefits from forests, mushrooms are an important forest food resource whose gathering has largely relied on indigenous knowledge systems (IKS). We surveyed five miombo woodland rural communities in central Zimbabwe with respondents of at least 16 years old, focusing on wild mushroom identification criteria used, ethnomycological knowledge transmission mechanisms, known mushroom foragers, known woody species associated with gathered mushrooms, and indigenous mushroom nomenclature systems used. Mushroom cap colour (99.52 %) was of similar importance to use of cap texture (95.78%) but more important (p ≤ .05) than cap shape, or other attributes. Women (69.04%) were more important (p ≤ .05) knowledge transmitters than other family members. Millipedes (91.79%) and insects (83.55%) constituted higher (p ≤ .05) mushroom foraging mention than other invertebrates. Julbernardia globiflora (84.16%) was more favourably mentioned (p ≤ .05) to associate with most mushrooms than other woody species. Mushroom nomenclature largely derived from their morphological traits, texture and habitat. The study demonstrates prevalence of moderately strong IKS and mushroom links to vegetation. These findings will help in ethnomycological research on aspects of miombo mushrooms and any relevant forest policy to benefit rural communities.

Forest mapping and monitoring in Africa using Sentinel-2 data and deep learning

We propose and investigate a method for creating large scale forest height maps at 10 m resolution from Sentinel-2 data using deep neural networks. In addition, we demonstrate how clear-cutting events can be detected in a time series of the resulting forest height maps. The network architecture is a convolutional neural network based on the U-Net architecture. The 13 Sentinel-2 spectral bands are resampled to 10 m spatial resolution and input to the U-Net, which outputs a map with per-pixel forest height estimates. The network is trained with ground truth data acquired from airborne lidar scanning surveys from three different geographical regions. They cover different types of forests: lowland tropical rainforest in the Democratic Republic of Congo, Miombo woodlands (dry forest) in Liwale, Tanzania, and submontane tropical rainforest in Amani, Tanzania. We demonstrate that the trained network generalizes to new geographical regions within the African continent with a mean average error of 4.6 m. This is on-par with a previously published method’s ability to generalize to new geographical regions within the same country. Clear-cutting events are detected using a t-test. The null-hypothesis of the t-test is that the forest height has not changed after any given point in time in the forest height time-series.

Effects of Income and Price on Household’s Charcoal Consumption in Three Cities of Tanzania

More than 80% of the urban and periurban population in Tanzania depend on charcoal as their main source of energy for cooking. This charcoal is supplied from natural forests, mainly Miombo woodlands, and the high charcoal consumption is a main trigger for deforestation, forest degradation, and climate gas emissions. The country’s urban population is increasing at an annual rate of 5-6%, and better understanding of the urban demand for charcoal is of high interest regarding the country’s energy development, climate mitigation, and land use. We surveyed 360 households situated in the Tanzanian cities Dodoma, Morogoro, and Mtwara and analyzed statistically the impacts of household income, charcoal prices, and household size on the per capita charcoal consumption. For the total sample, statistically significant elasticities were found to be 0.03, −0.13, and −0.62 for per capita income, charcoal price, and household size, respectively. In the low-income group, the elasticities of charcoal price and household size were found to be statistically significant with the values of −0.44 and −0.59, respectively, whereas in the middle-income group, the household size was the only statistically significant variable, with elasticity −0.81. In the high-income group, we got statistically significant elasticities of 0.17 for per capita income and −0.44 for household size. These results are based on small samples and should be followed up by larger surveys.