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Fynbos and afrotemperate forest exist as alternate stable states in the Cape Floristic Region of South Africa. In parts of Table Mountain National Park, afrotemperate forest has expanded in recent decades. The aim of this project was to explore the drivers of this change and distinguish whether this expansion represents a recovery of forest after previous clearance during the 18th century or is a novel expansion of forest range that resulted from policies of fire suppression in the 20th century. To determine the relationships between forest and fynbos and its key drivers, pollen, non-pollen palynomorphs, charcoal, stable isotope ratios (δ13C) and major and trace elements were analysed from late-Holocene sediments extracted from Orange Kloof. Pollen data show that forest cover has fluctuated over the past 3690 years. At the start of the record, under drier conditions from 1670 BCE to ~170 CE, forests contracted, and dry, asteraceous fynbos dominated the landscape. Around ~170 CE there was a shift to ericaceous fynbos as water availability increased. Weak signals of Khoekhoen pastoralists may be visible in the record around 50 CE, indicated by increased spores and charcoal. A regime shift towards increased dominance of the forest occurred ~250 CE, associated with wetter climate. Clear anthropogenic signals are associated with European settlement from 1650 CE. Reinforced by human clearance of forest, fynbos expanded during the cool conditions of the late phase of Little Ice Age (~1750–1850 CE). Forest expansion in the 20th century likely reflects fire suppression and recovery from past forest clearance. Fire needs to be managed accordingly if further expansion of forest into fynbos is to be curbed. [ABSTRACT FROM AUTHOR]

We explore the correspondence between changing palaeoenvironments, patterns of site use, and lithic technology at the rock shelter site Klein Kliphuis (South Africa) across the interval 65–55 000 years before present. This period coincides with the termination of Marine Isotope Stage (MIS) 4, and the disappearance of an iconic late Pleistocene archaeological unit known as the Howiesons Poort. Wood charcoals indicate sufficient soil moisture around Klein Kliphuis throughout the Howiesons Poort to support diverse tree species at a time when site occupation was relatively intense. At least some fuelwood‐gathering in this period may have been undertaken to support heat treatment of silcrete, which was the dominant lithology in tool production. A coherent set of changes occurs across the MIS 4/3 transition: occupational intensity declines, tracked by declining diversity of fuelwood species, an increase in the proportion of charcoals from shrubs and small flowering plants, lower prevalence of silcrete, and less heat treatment. While declining soil moisture is implied, there appears to be a significant change in behaviour relating to site usage, whereby foraging for dense fuelwoods was replaced by the construction of 'fast fires' that may reflect briefer visits and increased forager mobility in early MIS 3. [ABSTRACT FROM AUTHOR]

This paper presents the first insight into the interpretation of the wood charcoal from the Holocene layers of Wonderwerk Cave. Situated in the Northern Cape Province in the arid interior of South Africa, the site provides a unique and valuable chronological record of past environmental fluctuations and responding human behavioural adaptations spanning the last two million years. The Holocene strata have been dated to cover the last 12.5 ka cal BP years, but exclude the last 100 years because of contamination. A sizeable amount of charcoal was recovered from these strata and remnants have been identified, described and the species composition amongst the strata compared. Most identified species are those that tolerate hot, dry conditions, signalling an arid trend during the Holocene. Comparison with present day species distributions suggests an eastwards shift in modern vegetation. The charcoal data also indicate that during the mid Holocene there was a wetter period from 6.2 to 4.5 ka cal BP, coinciding with stratum 4a. [ABSTRACT FROM AUTHOR]

Palaeoecological evidence is compared with the existing archaeological record to understand how changing human activity, over the past two millennia, impacted fire regimes and vegetation dynamics in the Drakensberg Mountains, South Africa. Sediment cores from two wetland sites in the Cathedral Peak area of the northern Drakensberg, KwaZulu-Natal are dated using accelerator mass spectrometry to chronologically support biological proxy data. Fossil pollen analysis is used to detect changes in vegetation composition, and macroscopic charcoal to reconstruct changing fire regimes. Charcoal accumulation rates (CHAR) are used as a proxy for burned biomass, and charcoal width-to-length ratio (W/L) as a proxy for dominant fuel type, whether grassy or woody. Results indicate an increase in CHAR, coincident with the appearance of cereal-type grasses (>40 μm) c. 550 cal BP, suggesting a change in fire regimes associated with the arrival of early agropastoralists. A notable decline in charcoal W/L at this time indicates a shift towards a more grassy fuel type. This is consistent with a seasonal shift in the timing of ignitions from high intensity late season lightning fires to low intensity early season anthropogenic fires. The latter are less damaging to woody vegetation explaining an overall shift to a more grassy fuel type. Large scale ecosystem change is evident in the colonial period, including decreased forest pollen taxa such as Podocarpus, which may be linked to colonial period logging. The increased dominance of Pteridium spores documents the invasion trajectory of bracken fern into montane grasslands in the area, which is attributed to ecosystem disturbance in the form of colonial fire suppression. The subalpine wetland clearly documents woody encroachment of the surrounding open grassland landscape during the agropastoral and subsequent colonial periods. By contrast, at the montane wetland site, these trends appear to be overprinted by local forest dynamics and recent deforestation, likely an elevation effect. Palaeoecological evidence demonstrates how changes in fire regimes and vegetation composition in the northern Drakensberg are closely tied to human activity over the past two millennia. [ABSTRACT FROM AUTHOR]

Here we present charcoal identifications for Rose Cottage Cave, Eastern Free State, from layers dated between about 96,000 and 35,000 years ago (~96 and ~35 ka ago). We then suggest plant community types that might have been established in the area in warm Marine Isotope Stage 5 (MIS5) versus cooler MIS4/MIS3 phases. The hypothesis is that frost-tender plants should occur in warm phases while hardy Leucosidea sericea , Protea spp. and Erica spp. should be more common during cooler phases more recent than ~74 ka ago. Leucosidea sericea thrives under moist conditions and its presence in late MIS4 and in several MIS3 layers at Rose Cottage implies that the area may have been moister than many other sites in the interior of southern Africa, thereby making it attractive for occupation. The charcoal identifications at ~96 ka ago included taxa like Buddleja salvifolia that need somewhat warmer conditions than taxa such as Leucosidea sericea. Taxa diversity based on the charcoal identifications is generally low at the site throughout the Middle Stone Age, but the vegetation from relatively warm MIS5 seems more diverse than that of MIS4 and MIS3. Some taxa identified, for example, Calodendrum capense , Leucosidea sericea , Erica caffra and Protea caffra no longer grow near the cave although they are commonly found in other parts of eastern South Africa. [ABSTRACT FROM AUTHOR]

The Greater Cape Floristic Region (GCFR) of South Africa is a biodiversity hotspot of global significance, and its archeological record has substantially contributed to the understanding of modern human origins. For both reasons, the climate and vegetation history of southwestern South Africa is of interest to numerous fields. Currently known paleoenvironmental records cover the Holocene, the last glacial–interglacial transition and parts of the last glaciation but do not encompass a full glacial–interglacial cycle. To obtain a continuous vegetation record of the last Pleistocene glacial–interglacial cycles, we studied pollen, spores and micro-charcoal of deep-sea sediments from IODP Site U1479 retrieved from SW of Cape Town. We compare our palynological results of the Pleistocene with previously published results of Pliocene material from the same site. We find that the vegetation of the GCFR, in particular fynbos and afrotemperate forest, responds to precessional forcing of climate. The micro-charcoal record confirms the importance of fires in the fynbos vegetation. Ericaceae-rich and Asteraceae-rich types of fynbos could extend on the western part of the Paleo-Agulhas Plain (PAP), which emerged during periods of low sea level of the Pleistocene. [ABSTRACT FROM AUTHOR]

In southern Africa, archaeobotanical studies are intrinsically linked to prehistoric investigation and the discipline of anthracology has already proved its potential for palaeoenvironmental and palaeoecological reconstructions. While the region benefits from particularly good preservation of macro charcoal remains in its sites, anthracological studies remain underexplored and the methodological framework still needs to be developed and adapted to the diverse southern African ecological contexts. Here we provide a review of sampling methods and sample representativeness and we compare it with wood charcoal analyses performed in southern Africa. We used the charcoal-rich layers from the Later Stone Age sequence of Bushman Rock Shelter (BRS) to elaborate a sampling strategy producing samples that can both be analysed in a timely manner and that are statistically representative of the whole assemblage. In light of our results, we discuss the relevance of applying anthracological methods developed in European contexts. The evaluation of the taxa richness, diversity and size distribution at BRS leads to the recommendation of the identification of at least 500 charcoal fragments per stratigraphic unit. Thick layers should be split into two distinct samples, one comprising the top half and the other one the bottom half of the layer. The analysis of thin layers with limited charcoal abundance necessitates increasing the surface of sampling. All size-classes should be analysed to avoid any sampling bias. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the Sibudu Cave habitat that is dated to the late Pleistocene using archaeological wood charcoal, in order to reconstruct the environment and the activity of the people who interacted with the landscape. Standard anthracology procedures were applied in this qualitative study to analyse charcoal remains from the cave. A representative subset of charcoal remains was subsampled from a larger assemblage and environmental data, as well as evidence of wood use, are interpreted from 72 charcoal types that include 42 types that we identified taxonomically. We highlight that the environment at Sibudu supported a multi-layered Forest with Savanna vegetation based on the presence of many important taxa of these vegetation communities. The wood of the identified taxa has much rot fungi and was also burrowed by pests; however, it is not possible to infer at this stage if the fungi seen here were pathogenic. The presence of fungi is indicative of an environmental setting with high humidity and warm temperatures, such as is optimal for these types of fungi to flourish. Climatic conditions interpreted here agree with previous interpretations that were made from other environmental proxies. These conditions were only intense enough to disturb the microhabitat at Sibudu and did not change the vegetation near the cave. Also noted during the analysis, is that burning wood logs that were infected with brown rot consistently from c.73 to 72 ka probably produced very warm fires. [ABSTRACT FROM AUTHOR]

With a rich sequence of floral and faunal remains spanning the past >65,000 years, Boomplaas Cave is among the more important paleoenvironmental archives from South Africa's southern Cape. However, over the last several decades, its paleoenvironmental records have been the subject of conflicting interpretations, fueling uncertainty over fundamental aspects of Quaternary climate change in the region. Most significantly, researchers have variably interpreted the fossil plant and animal assemblages dating to the Last Glacial Maximum (LGM) as indicating harsh and arid or humid and productive conditions. This review critically examines the paleoenvironmental evidence from Boomplaas Cave, focusing on its LGM deposits and how they relate to the contentious problem of moisture availability through time. We show that interpretations of aridity during the LGM either (i) lack robust ecological links between the evidence and the paleoenvironmental interpretation, or (ii) are based on spurious patterns arising from sampling effects. In contrast, interpretations of relatively humid conditions during the LGM are grounded in present-day ecological observations and are consistent with both local and regional paleoenvironmental datasets. Overall, the evidence strongly supports the characterization of the LGM as a time of relatively humid conditions, with the transition to the Holocene characterized by increasing aridity. Several lines of evidence from Boomplaas Cave further suggest that this phase of increased humidity was associated with a dominance of winter rainfall, in contrast to the aseasonal rainfall regime that characterizes the southern Cape today. • Boomplaas Cave is a critical but debated archive of LGM climate in southern Africa. • This study examines its paleo proxies and the interpretations derived from them. • The proxy records indicate greater moisture availability during the LGM. • The proxy records indicate a greater dominance of winter rainfall during the LGM. [ABSTRACT FROM AUTHOR]

Fire is a natural phenomenon along South Africa's southern Cape coast, but identifying its climatic drivers has been a subject of considerable debate. This study investigates the hydroclimatic and fire dynamics from a 9.6 m sediment core from Vankervelsvlei covering the past 7.2 ka. The fen is located near the southern Cape coast within the year-round rainfall zone of South Africa. A reconstruction of hydroclimatic variability through time applies oxygen isotopes from hemicellulose-derived sugars and hydrogen isotopes from leaf wax-derived n -alkanes. Coupling both isotopes enables a reconstruction of the atmospheric source and seasonality of precipitation as well as estimating local relative humidity. Past trends in fire activity are inferred from macro-charcoal and polycyclic aromatic hydrocarbon (PAH) analyses, the latter serving as fire biomarkers. Results indicate high fire activity at Vankervelsvlei accompanied by generally moist conditions and a year-round rainfall regime linked to both Westerly-derived winter precipitation and Easterly- and locally-derived summer precipitation from 7.2+0.2/ −0.2 to 4.5+0.3/ −0.3 cal ka BP. From 4.5+0.3/ −0.3 to 1.5+0.4/ −0.2 cal ka BP, a shift to a Westerly-derived winter rainfall regime is identified. This variation features alongside reduced fire activity and persistent drought conditions as Easterly- and locally-derived summer precipitation decreased. From 1.5+0.4/ −0.2 cal ka BP until present day, macro-charcoal and PAH accumulation rates show high fire activity. Paleoclimate evidence from the last two millennia suggests a variable climate with an overall increase in total moisture availability as contributions from both Westerly-derived winter precipitation and Easterly- and locally-derived summer precipitation support the year-round rainfall regime present today. Results from Vankervelsvlei support previous evidence from regional paleo-reconstructions, refining our understanding of the interplay between hydroclimatic variability and fire activity along South Africa's southern Cape coast. Our study discusses the role of large-scale climate modes, specifically the intensity of El Niño, as a potential driver of short-term hydroclimatic variability, which in turn drives fuel availability and fire activity at Vankervelsvlei during the Holocene. • Fire reconstruction based on macro-charcoal and polycyclic aromatic hydrocarbons. • Hydrological reconstruction based on coupling δ2H n -alkane –δ18O sugar. • During moist periods, fire activity is high due to high biomass availability. • Fire activity is low due to low biomass availability during dry periods. • El Niño is a potential driver of short-term hydroclimatic variability. [ABSTRACT FROM AUTHOR]

Charcoal rot incidence in soybean and sunflower in South Africa is increasing. Irrigation as a means to manage charcoal rot is limited as water resources are decreasing and oil seed production is predominantly on dry land. The effect of reduced soil moisture on charcoal rot incidence, severity and colonization of host tissues, as well as subsequent yield loss, was investigated under optimal and sub-optimal conditions for disease development on hosts grown in rotation with Zea mays (maize). Pot experiments were carried out in a greenhouse using a locally planted Glycine max (L.) Merr. (soybean) and Helianthus annuus L. (sunflower) cultivar, which were inoculated with Macrophomina phaseolina (Tassi) Goid. Isolated from sunflower grown in a major oil seed-producing region in South Africa. The disease index, calculated as the product of incidence and severity divided by the total number of observations made per treatment, ((incidence × severity)/(total number of observations made per treatment)), was 20% higher in soybean than in sunflower, even though colonization of sunflower, calculated as the frequency of M. phaseolina isolated from the stem section between the roots and the cotyledon, was 10% more than that of soybean. M. phaseolina was not isolated past the first node of either crop. Yield loss due to charcoal rot amounted to 6.13% in soybean and 12% in sunflower, relative to the uninoculated, reduced soil moisture controls. Microsclerotia were more concentrated in soybean than in sunflower, which indicates that a soybean crop could increase soil inoculum more readily than sunflower. Consideration should therefore be given to the charcoal rot susceptibility of the crop following soybeans. Reduced soil moisture and infection were synergistic to disease incidence and yield loss, but independent of colonization and disease severity. Results showed that an increase in soil moisture cannot prevent initial infection of the host, but can significantly reduce colonization of the stem at maturity. • Irrigation did not prevent infection by M. phaseolina, but reduced disease severity. • Increased colonization of sunflower plants by M. phaseolina resulted in higher yield loss. • Microsclerotia concentration was higher in soybean than sunflower. [ABSTRACT FROM AUTHOR]

Wonderwerk Cave in the Northern Cape Province of South Africa has a record of occupation spanning some 2 million years, comprising flora, fauna and cultural artifacts and, therefore, potentially, has the most complete macrobotanical record associated with hominin/human activities. The flora is described here for the lower levels: the Oldowan Stratum 12 ( ca. 2 Ma) to the Late Pleistocene Stratum 5 ( ca. 14 ka). The older material includes calcified roots, leaf litter of small dicotyledonous twigs and seeds, grass and sedge culms. From Stratum 5, there are about 134 pieces of charcoal that have been identified to eight woody species. Assuming the firewood was of local origin, the climate during the latest Pleistocene would have been slightly more mesic than today's arid to semi-arid climate. [ABSTRACT FROM AUTHOR]

The generation of coal chars is an important intermediate step in coal conversion processes such as combustion and gasification. The char structure impacts their behaviour in these processes. Detailed investigations on slow-heated coal chars utilizing molecular modelling approaches are limited in comparison to the more extensive work on coal. Also South African (SA) coal is generally not as well studied as the vitrinite-rich coals in the Northern Hemisphere. Both inertinite-rich and vitrinite-rich coals are available in SA, formed with the same inputs but in different depositional environments, thus providing an opportunity to examine maceral influences without the challenges associated with maceral separation. Experimental work was performed to characterize de-ashed chars generated by heating the inertinite- and vitrinite-rich South African Gondwana coals of the Permian Age under inert atmosphere (nitrogen gas) to 1000 °C at a rate of 20 °C/min and maintain this temperature for 60 min before cooling. Experimental work included petrographic analysis, elemental analysis, helium density, 13 C NMR, XRD, and HRTEM analyses. The maceral purity was enhanced with density separation prior to pyrolysis. Analytical data was used to construct molecular structures comprising polyaromatic hydrocarbons with oxygen, nitrogen and sulphur functionalities. Aromaticity and skeletal density measurements provided additional constraining data. The inertinite-rich char model comprised 8586 atoms comprising 21 individual molecules with a composition (normalised to 1000 carbon atoms) of C 1000 H 105 O 14 N 22 S 1 , while the vitrinite-rich char model was 8863 atoms within 37 molecules with a normalised composition of C 1000 H 125 O 21 N 22 S 3 . The two chars were thus chemically similar; however, the size of polyaromatic molecules differed, as observed from HRTEM and XRD data. The inertinite-rich chars contained larger molecules ( L a (10) = 37.61 ± 2.32 Å) than the vitrinite-rich chars ( L a (10) = 30.74 ± 0.77 Å). This will influence the fraction of active carbon sites located on the crystallite edges and defects of the basal planes that may contribute to the lower reactivity of inertinite-rich chars in comparison to vitrinite-rich chars. Atomistic representations of these chars was constructed capturing a portion of the structural diversity observed from image analysis of the HRTEM lattice fringe micrographs. While the char generation parameters used in this study produced similar chars derived from the South African inertinite- and vitrinite-rich coals, the crystallite diameter, L a , was found to be the property that distinguished the two chars significantly. This may hold promise for exploring structural-reactivity relationships. [ABSTRACT FROM AUTHOR]

Middle Stone Age technological and behavioural developments in southern Africa are central to understanding the emergence of modern humans, and elucidating the role of environmental change in this trajectory is dependent on emerging palaeoclimatic reconstructions. Climate proxies from Middle Stone Age sites are often poorly preserved, coarsely resolved or subject to anthropogenic selection and are not considered in favour of global environmental proxies despite the fact that the modern climate regimes at the relevant archaeological sites differ profoundly. Sibudu has a well-preserved Middle Stone Age sequence that has yielded abundant palaeoclimate proxy data. Isotopic analysis of charcoal, charcoal anatomy and species representation, macro- and micro-faunal remains, sediment texture, mineralogy and magnetic susceptibility, pollen and macrobotanical remains provide evidence for the environmental succession specific to this site. The isotopic data suggest that archaeological charcoal was not significantly post-depositionally altered. During the Howiesons Poort (65-62 ka) the local environment was thickly forested, moist and more humid than during the 58 ka occupations. The environment changes during the post-Howiesons Poort occupation (~58 ka) into the late MSA occupation (~48 ka); conditions became drier and colder than present with vegetation shifting to open savanna grassland or woodlands. [ABSTRACT FROM AUTHOR]

Abstract: The Cederberg Mountains (Western Cape Province, South Africa) are located within the Fynbos Biome, which exhibits some of the highest levels of species richness and endemism in the world. The region's post-glacial vegetation history, however, remains largely unknown. Presented here are high resolution pollen and microcharcoal records spanning the last 15,600years obtained from the De Rif rock hyrax midden from the Driehoek Valley of the central Cederberg. In this region, previous pollen studies have shown muted variability in vegetation community composition during periods of globally marked climatic variability (e.g. the last glacial–interglacial transition). In our record, however, significant changes in vegetation composition are apparent. Most notably, they indicate a shift from ericaceous/restioid fynbos (present from 15,600 to 13,300calyr BP) to a brief, but prominent, development of proteoid fynbos at the beginning of the Holocene around 11,200calyr BP. This vegetation shift is associated with increased moisture at the site, and coincides with reduced fire frequency as indicated by the microcharcoal record. At 10,400calyr BP, there is a marked reduction in Protea-type pollen, which is replaced by thicket, characterised by Dodonaea, which became the dominant arboreal pollen type. This shift was likely the result of a long relatively fire-free period coupled with warmer and wetter climates spanning much of the early Holocene. A brief but marked decrease in water availability around 8500–8000calyr BP resulted in the strong decrease of Dodonaea pollen. The vegetation of the mid- to late Holocene is characterised by the increased occurrence of Asteraceae and succulent taxa, suggesting substantially drier conditions. These data give unprecedented insight into the vegetation dynamics across a period of substantial, rapid climate change, and while they confirm the presence of fynbos elements throughout the last 15,600years, the results highlight significant fluctuations in the vegetation that were triggered by changes in both climate and fire regimes. [Copyright &y& Elsevier]

Abstract: The thermal treatment of coal causes a development of internal porosity of the resultant char due to the changes in the coal char pores, i.e. the opening of original closed pores, the formation of new pores, and an increase in pore size of existing and newly formed pores. Furthermore, the porosity formed during de-volatilisation causes changes in pore structural characteristics such as: density, pore size distribution, total open pore volume, porosities and average pore diameter. Much research has been conducted in this area, but was mainly focused on fine particle sizes (<1mm) and vitrinite-rich coals, particularly from the Northern hemisphere. The objective of this study was to obtain an understanding of both the macro- and micro-porosity development within the de-volatilisation zone of a packed bed consisting of lump inertinite-rich coal (75mm×6mm) from the Highveld coalfield in South Africa. This was achieved by generating samples in an air-blown packed bed reactor and conducting proximate, CO2 reactivity, mercury intrusion porosimetry, and BET CO2 surface area analyses on the dissected coal/char/ash samples. From mercury-intrusion porosimetry results obtained for the de-volatilisation reaction zone of the reactor, it was found that although the percentage macro-porosity and average pore diameter increased by 11% and 77% respectively (which confirms pore development), that these developments do not enlarge the surface area, and thus has no significant contribution on the reactivity of the coal/char. On the other hand, the micro-pore surface area, pore volume and pore diameter were all found to increase during de-volatilisation, resulting in an increase in the coal char reactivity. The micro-porosity is thus generally responsible for the largest internal surface area during de-volatilisation, which enables increased reactivity. The CO2 gasification reactivity (at 1000°C) increased from 3.8 to 4.5h−1 in the first stage of de-volatilisation, and then decreased to 3.8h−1 in a slower de-volatilisation regime. This is due to the maximum pore expansion and volatile matter evolution reached at 4.5h−1, before coalescence and pore shrinkage occur with a further increase in temperature within the slower de-volatilisation region of the reactor. During de-volatilisation there is thus both an increase and decrease in reactivity which might suggest two distinct intermediate zones within the de-volatilisation zone. [Copyright &y& Elsevier]

Abstract: Biomass from three invasive plant species of the Western Karoo region in South Africa, namely Kraalbos, Schotzbos and Asbos, was treated by vacuum pyrolysis. The influence of temperature, pyrolysis time, pressure and initial moisture content on the bio-oil and charcoal yields were investigated. Asbos with the largest ash content, 19.9wt.%, gave chars with an ash content between 40wt.% and 44wt.% making it difficult to use commercially. Vacuum pyrolysis of Kraalbos resulted in producing a biochar with a HHV of 23.0–25.5MJ/kg and an ash content of 13–19wt.% which compared favourable with commercial charcoal. The bio-oils from both Kraalbos and Schotzbos showed promise as potential heating oil with a HHV of 21.6–26.9MJ/kg. The tarry phase contained a number of phenolic compounds that can be separated and shows promise as a feedstock for upgrading. Finally ageing which acts on the lignocellulosic structure of biomasses decreased the charcoal and oil yields from the vacuum pyrolysis of intruder plants. [Copyright &y& Elsevier]

Abstract: Many South African medicinal plants are over-collected for use in traditional medicines. This necessitates developing methods for increasing production. Micropropagation can be used as an alternative to conventional propagation methods. Twin-scales, cut from large parent bulbs, were cultured on MS medium () supplemented with 25 plant growth regulator combinations. Bulblets formed on twin-scales in 24 of the treatments. All explants formed bulblets on plant growth regulator-free medium. The effect of plant growth regulators, activated charcoal, explant orientation, explant origin and photoperiod on bulblet production was investigated. Bulblet formation was greatest when twin-scales were excised from the middle of the parent bulb, placed adaxial side down on plant growth regulator-free medium and kept in a 16h photoperiod. [Copyright &y& Elsevier]

Roughing filtration is an important pre-treatment process for wastewater, because it efficiently separates fine solid particles over prolonged periods, without the addition of chemicals. For this study, a pilot plant was designed at Delmas Coal Mine in the Mpumalanga province of South Africa. The design and sizing of the pilot plant was guided by Wegelin's design criteria. Gravel was used as a control medium because it is one of the most commonly used roughing filter media and because it was used in developing the criteria. We compared the performance of gravel as a filter medium to that of another locally available material, charcoal, for the removal of turbidity in wastewater. The pilot plant was monitored continuously for 90 days from commissioning until the end of the project. The overall performance of the roughing filter in turbidity removal, using gravel or charcoal, was considered efficient for the pre-treatment of waste water. Charcoal performed slightly better than gravel as a filter medium for the removal of turbidity, possibly because charcoal has a slightly higher specific surface area and porosity than gravel, which could enhance sedimentation and other filtration processes, such as adsorption, respectively. [ABSTRACT FROM AUTHOR]

An elevated valley-fill peat bog (Wilson Bog) near Mount Lofty, South Australia, failed in November 2005 following a flooding event, and exposed representative sections of the sediment infill. Two distinct units were revealed: 2 m of coarse-grained, siliciclastic sand/gravel, overlain by 2 m of peat.Asimple charcoal extraction technique based on floatation and skimming was developed to extract coarse charcoal from coarse-grained gravels to determine the palaeofire record at a proximal site of sedimentation. Optically stimulated luminescence (OSL) dating of basal sediments revealed a minimum age of deposition of 7.02 +0.50 -0.56 ka, while the oldest charcoal peak yielded a radiocarbon age of 6000-5740 cal. yr BP. The lower half of the siliciclastic unit contains three distinct charcoal peaks suggesting there were infrequent but intense fires associated with wetter conditions during the Holocene climatic optimum 8000-5000 years ago. The period from 4000 to 2000 cal. yr BP is characterised by more frequent charcoal peaks and higher background levels of charcoal, which is consistent withmore regular but less intense fires during drier, cooler conditions. The sharp transition from siliciclastic sedimentation to peat formation began ∼1200 cal. yr BP, which may relate to a return to wetter conditions. However, fire frequency appears to have increased in this time suggesting augmentation by anthropogenic or ENSO-related factors. Charcoal-rich layers in the siliciclastic unit are associated with poorly sorted, bimodal sediments with high proportions of clay, silt and gravel, which supports the hypothesis that there is an association between past fire events and rapid, coarse-grained, post-fire aggradation. By analogy with active colluvial aggradation following recent fires at nearbyMount Bold, it is evident that fire plays a significant role in hillslope destabilization and subsequent sediment movement, leading to rapid valley- fill aggradation - a chain of events to which we apply the term 'pyrocolluviation'. [ABSTRACT FROM AUTHOR]

Abstract  Understanding the interplay between climatic and anthropogenic factors is a major challenge in palaeo-ecology. In particular, it is often difficult to distinguish anthropogenic and “natural” fire in the charcoal record. In this paper, analysis of fossil pollen, charcoal, diatoms and isotopic evidence from Mapimbi, a small lake in the Kruger National Park, South Africa, suggests that for most of the past ca. 700 years, the riverine gallery forests surrounding Mapimbi were primarily influenced by climate, and benefited during warmer, wetter periods. The transitions between four, statistically different phases in the time-series data coincide with regional climate records previously constructed from speleothem data, and are consistent with the transition from the medieval warm period ending in the 14th century a.d. to the cooler, drier conditions prevailing during the little ice age of ca. a.d. 1400–1800. The data also suggest a period of significant, anthropogenic influence after a.d. 1800, when maize was grown and the incidence of localised fires increased. An increase in woody cover in recent decades may be associated with the management of the area by Kruger National Park. A decline in cultivation occurred in the end of the 20th century linked with changes in socio-political organisation. [ABSTRACT FROM AUTHOR]

Abstract: Savanna ecosystems of southern Africa are strongly influenced by water availability and fire intensity, and this study aimed to show whether these two specific environmental variables are reflected in fossil pollen and charcoal records. Palaeoecological records of charcoal concentration from three short sedimentary sequences were used to reconstruct fire intensity (the rate of energy released along a fire front) over 50 yrs in the Kruger National Park (KNP), South Africa. Fossil pollen percentages from surface and core-sediment samples taken from water bodies were compared with the reconstructed fire intensity over space and time. Higher fire intensity led to increased herbaceous cover and decreased woody plant growth. Fossil pollen percentages and charcoal concentrations were also compared with rainfall records. Increased macroscopic charcoal abundances and percentages of Cyperaceae pollen corresponded to periods of increased rainfall. The results of this study have shown that fossil pollen and charcoal records from savanna environments can be used to reconstruct past fire intensity and its impact on terrestrial vegetation, as well as changes in rainfall. [Copyright &y& Elsevier]

The charcoal record contained in lake sedimentary sequences is often used to infer past fire events. Studies to calibrate such charcoal records have been carried out in a range of mid- to high-latitude regions and relationships have been determined between size and quantity of charcoal in the sediment and proximity and spatial extent of the fires. Very little is known, however, about the relationship between fire events in savanna ecosystems and how these are represented in the charcoal record in lake sedimentary sequences. This study presents the results of a project that aimed to calibrate the micro- and macroscopic charcoal record from Kruger National Park, South Africa, with known fire events. Surface sediment samples were analysed for charcoal of different size classes and compared with data on fire proximity, area and intensity (the rate of energy released along a fire front) from fire events over the last 10 years, and the relevant source areas for micro- and macroscopic charcoal were quantified. Results indicated that (i) the Relevant Source Area of Charcoal for lakes c. 200 m diameter is between 0 and 5 km for charcoal particles >50 μm in length and between 10 and 15 km for charcoal particles <50 μm; (ii) that charcoal deposits are most likely to represent combined fire events from the preceding five years; (iii) that fire proximity, area and intensity are each significantly represented in the charcoal record, but not equally, as the signal resulting from fire intensity is stronger than that for fire proximity or area. Mathematical equations linking charcoal with fire proximity, area and intensity are presented. [ABSTRACT FROM AUTHOR]

Carbonized seeds, nuts and the stones of fruits are present in Middle Stone Age (MSA) layers at Sibudu Cave from more than ∼60 ka ago to about ∼37 ka ago. In spite of the preservation of at least 66 taxa, the lack of comparative material allowed for the identification of only 35 taxa to family, genus or species. The remaining taxa were assigned Type numbers. The identified taxa consist of sedges, grass and woody climbers, shrubs and trees that are mostly present in the evergreen forest, forest margins and riverine vegetation in the shelter environs, or occur in similar habitats nearby. The sedges indicate the presence of open water, probably in the Tongati River, and they may have been harvested by people throughout the MSA sequence. Because of the widespread distribution and the wide range of environmental tolerances of many of the identified woody plants, various likely interpretations about vegetation change are possible and the taxa on their own provide inconclusive evidence of vegetation change during the MSA occupations at Sibudu. Frequency distributions of evergreen and deciduous taxa were compared through time. Taxa identified by charcoal analyses were combined with seed data to increase the sample size and provide more comprehensive representation of the prevailing vegetation. When the taxa are grouped according to age clusters, evergreen woody taxa appear to predominate at about 60 ka, followed by a marked increase in deciduous taxa. This trend may alter when larger reference collections allow for identification of more of the unidentified seed and charcoal taxa. The increase in deciduous taxa occurs at a time of gradual warming indicated by magnetic susceptibility studies, but it is unclear exactly how the increase relates to moisture availability and temperature. The trend may be interpreted as an indication of a greater deciduous element in the forest, or of more open vegetation near Sibudu Cave around ∼50 ka ago than was previously the case. [ABSTRACT FROM AUTHOR]

Analysis of charcoal from Middle Stone Age layers in Sibudu Cave shows evidence for environmental change and wood selection during the Last Glacial. Layers analysed encompass the end of the cold stadial, Oxygen Isotope Stage (OIS) 4, and the warmer interstadial, OIS 3. Layers are grouped into > 60 ka, ∼60 ka, ∼50 ka and ∼37 ka assemblages. Pre-60 ka layers within the Howiesons Poort (HP) occupations are dominated by evergreen forest taxa, including Podocarpus spp., Buxus sp., Brachylaena sp., Sapium/Spirostachys and Ptaeroxylon obliquum. Kirkia sp. suggests that a warm, woodland savanna habitat grew beyond the forest vegetation. At ∼60 ka there are taxa from evergreen, riverine forest communities, including Erica spp., Leucosidea sericea and Rapanea melanophloeos. Some of the taxa in these layers suggest a shift in vegetation, possibly related to the marine regression of the Last Glacial. A lowered sea-level and slightly cooler climates in South Africa may have enabled taxa currently found farther inland in the mountain foothills to grow closer to the rock shelter than at present. By ∼50 ka, fewer evergreen forest components and more bushveld taxa, which are common in northern, drier regions of South Africa, are present. These ∼50 ka layers also contain more Acacia spp. and other Fabaceae taxa, and fewer Erica spp., than the samples from the ∼60 ka layers. This may be a result of environmental change, a change in wood selection, charcoal fragmentation, or sampling bias. At ∼37 ka, there are evergreen and deciduous taxa, many of which grow in KwaZulu-Natal today, while Kirkia sp. again provides evidence for a dry habitat. Taxa that are currently unidentified may indicate that a vegetation community existed for which there is currently no reference material. Fuel-woods commonly used by modern societies in Africa were routinely collected by ∼60 ka. In contrast, the pre-60 ka HP layers are dominated by Podocarpus spp. and the 'good' fuel-woods, Acacia spp. and Erica spp., are absent. This pattern may be a result of changes in the local vegetation, sample bias or simply a different approach to wood collection and use between the HP and ∼60 ka occupations. [ABSTRACT FROM AUTHOR]

We present 21 radiocarbon dates on 19 charcoal samples from the sedimentary sequence preserved in Border Cave, South Africa. The background radiocarbon activity for charcoal from the cave was determined to be 0.050±0.018 percent modern carbon, from the analysis of a radiocarbon-dead sample from unit 5WA. Radiocarbon ages for individual samples ranged from 25.2 to >58.2 ka BP.The error-weighted mean ages for successively older strata are 38.5+0.85/−0.95 ka BP for unit 1WA, 50.2+1.1/−1.0 ka BP for units 2BS.LR.A and 2BS.LR.B, 56.5+2.7/−2.0 ka BP for unit 2BS.LR.C and 59.2+3.4/−2.4 ka BP for unit 2WA. This radiocarbon chronology is consistent with independent chronologies derived from electron spin resonance and amino acid racemization dating. The results therefore provide further evidence that radiocarbon dating of charcoal by the ABOX-SC technique can yield reliable radiocarbon ages beyond 40 ka BP. They also imply that Border Cave 5, a modern human mandible, predates >58.2 ka BP and that the Middle Stone Age (Mode 3)—Later Stone Age (Mode 5) transition of Border Cave was largely effected between ∼56.5 and ∼41.6 ka ago. [Copyright &y& Elsevier]

Preliminary research at Sibudu shows that the cave contains a palimpsest of Middle Stone Age layers. The upper layers are dated by radiocarbon to between 42 000 and 26 000 b.p.; the deeper layers have been sampled for luminescence dates, but results are not yet available. Bone, charcoal and burnt seeds are well preserved in all layers excavated thus far. Stone tools are abundant in all except the deepest layers of the present excavation. Unifacial and bifacial points are the most common retouched tools, but scrapers, knives and adzes are also present. [ABSTRACT FROM AUTHOR]

Test excavations at Adullam Cave show that it contains a palimpsest of undated Oakhurst Industry occupations and an ephemeral recent Later Stone Age occupation. Faunal remains include Burchell's zebra and bovids in the size range one to three. Charcoal analysis suggests that the vegetation near the site was of low species diversity. [ABSTRACT FROM AUTHOR]

Presents information on a study which examined wood charcoal and pollen from terminal Pleistocene-dated levels at Africa's Elands Bay Cave. Methodology and results of the study; Conclusions.

Mpondoland on the South African east coast is a particularly dynamic region in terms of climate change as it is influenced by both temperate and tropical circulation and climate systems. We present a sediment record that indicates regional climatic change and anthropogenic influence during the last ∼5500 yr. Catchment data allow an understanding of signal transmission from the catchment to the site of the marine core. Plant-wax isotope distributions and elemental composition, as well as palynological, burned phytolith and micro-charcoal data, are used to infer paleoclimatic shifts and reconstruct past human activity. Whereas previous studies have often disregarded early anthropogenic drivers of environmental change, our study provides palynological evidence of human impacts and geochemical evidence of increased erosion starting as early as ∼1500 years ago. Downcore proxy analysis suggests that particularly humid conditions persisted from ∼900 to ∼300 cal yr BP, encompassing both the Medieval Climate Anomaly and the Little Ice Age. We suggest that humidity during the Medieval Climate Anomaly was sourced from a poleward shift of the Southern Hemispheric Westerlies and the South African high-pressure cell, allowing for the southward expansion of the Southern Indian Ocean Convergence Zone. During the Little Ice Age, the equatorward movement of the Southern Hemispheric Westerlies probably brought increased rainfall to areas that are normally beyond the northern limit of the Southern Hemispheric Westerlies. Comparison of our record to available regional archives of centennial-scale late Holocene climate variability in South Africa demonstrates that Mpondoland is located at a transition zone of tropical and sub-tropical climatic influences. • Anthropogenic drivers of environmental change as early as ∼1500 years ago. • A southward expansion of the Southern Indian Ocean Convergence Zone caused a wet Medieval Climate Anomaly in Mpondoland. • A Southern Hemispheric Westerlies equatorward shift brought increased rainfall to Mpondoland during the Little Ice Age. [ABSTRACT FROM AUTHOR]

Summary Aim The aim of this paper is to analyse fossil charcoal deposits, largely identified to the species level and spanning a sequence from the late Holocene to < 40,000 BP, in order to reconstruct Late Quaternary vegetation and climatic patterns in the western (winter-rainfall) fynbos biome of South Africa. Location The charcoals were excavated from the Elands Bay Cave (32°19S, 18°20E) on the semiarid (200–250 mmyr-1 ), winter-rainfall coastline of the western fynbos biome. Methods Patterns in the charcoal data set over time were sought by manual sorting of the charcoal×sample matrix, as well as by subjecting the data to multivariate analysis. Palaeoclimatic reconstruction was attempted by comparing the climatic controls on contemporary vegetation communities that resembled the fossil assemblages. Charcoal diversity was modelled using sample age and number of charcoal fragments as explanatory variables. Results The fossil assemblages ranged from xeric communities (similar to those presently occurring at the site) during the Holocene, to more mesic thicket and fynbos vegetation in the terminal Pleistocene, to Afromontane forest and riverine woodland communities after about 18,000 BP. Diversity of the charcoal samples increased monotonically with increasing sample age. Main conclusions The results suggest that, unlike the eastern fynbos biome, which is under fundamentally different climatic controls, soil moisture conditions in the western part of the biome were higher in the Last Glacial than during the Holocene. This scenario may help to explain the higher regional richness and associated diversification in the western than eastern part of the biome. [ABSTRACT FROM AUTHOR]

The mid-Piacenzian Warm Period (mPWP, 3.264–3.025 Ma) of the Pliocene epoch has been proposed as an analog for future climate scenarios. Disagreement between the paleoenvironmental reconstruction and model simulations of the climate in subtropical regions for this period suggests that more investigation of the subtropical climate variability of the mPWP is needed. This study presents pollen, microcharcoal and benthic foraminifera oxygen isotope records generated from marine sediment cores of International Ocean Discovery Program (IODP) Exp. 361 Site U1479 from the Cape Basin offshore of South Africa for the period between 3.337 and 2.875 Ma. With an average sample resolution of 3 ka, this record represents the highest-resolution record of mPWP vegetation change from the region. Our results indicate that the vegetation during the mPWP was dominated by fynbos (species-rich heathy vegetation in the Cape Floristic Region) with variable proportions of Ericaceae. Moreover, the development of the Afrotemperate forest (tall, multilayered indigenous forests in South Africa) reflects shifts in the amounts of precipitation between winter and summer in the year-round rainfall zone. The vegetation variation is probably influenced by the latitudinal insolation gradient in response to precession forcing. Several glacials depicted by the benthic foraminifera oxygen isotope record were characterized by lower percentage values of Restionaceae, higher percentage values of ericoid fynbos and Afrotemperate forest. These events correspond well with cooler SE Atlantic sea surface temperatures driven by interactions of both atmospheric and oceanographic processes. The cooler sea surface temperatures attributed to Antarctic ice sheet expansion, reduced Agulhas leakage (heat and salt transfer from the Indian Ocean to the Atlantic Ocean) and/or intensified southern Benguela upwelling, resulted in less precipitation in the winter rainfall zone of South Africa. • A multiproxy approach using pollen, microcharcoal and benthic foraminifera δ 18 O • Highest-resolution records during the mid-Piacenzian Warm Period in the Cape region. • Vegetation dominated by fynbos with variable proportions of Ericaceae. • Influence by the latitudinal insolation gradient in response to precession forcing. • Sea surface temperature forcing. [ABSTRACT FROM AUTHOR]

This report proposes a refined method to date archaeological gold samples based on the Tafel analysis of the ascending part of voltammetric curves corresponding to the oxidation of surface flakes of gold in contact with hydrochloric acid aqueous electrolyte. This allows estimating the equilibrium potential of gold oxidation correcting for irreversibility effects. This equilibrium potential can be correlated with the coverage of adsorbed oxygen species and hence the estimated age of the gold samples. A satisfactory potential/time calibration graph was constructed from a set of archaeological samples including two sets of samples from the Mapungubwe Gold Collection, South Africa (1200–1290 CE) and Santa Llúcia, Alcalà de Xivert in Spain (dated back 600-550 BCE) sites. The dated samples come not only from different continents, but their ages also cover more than 3000 years. Image 1 • Electrochemical dating of archaeological gold samples is based on the voltammetry of immobilized particles. • Samples from the Mapungubwe Gold Collection (1200–1290 CE) and Santa Llúcia archaeological site (600-550 BCE) were studied. • Peak potentials and peak currents for gold oxidation in 0.10 M HCl are used. [ABSTRACT FROM AUTHOR]

A multi-proxy approach conducted on a sediment core from a small lake in the Cape Flats (Princessvlei, South Africa), supported by five AMS dates, reveals the paleoenvironments over the last 3900 years. Despite some gaps in the records, phytoliths, diatoms, δ18O diatom , pollen, coprophilous fungus spores, microscopic charred particles (micro-charcoal), and burnt-grass phytoliths, indicate vegetation disturbances caused by climatic changes, anthropogenic influences, fire, and herbivore activity. Pollen spectra indicates a moist period (3600-2600 cal yr BP), which co-occurs with an increase in fires, possibly due to greater biomass fuel loads coupled with the moderate presence of large herbivores. Subsequently, a dry period (2600-1900 cal yr BP) saw a rapid increase of large herbivores probably congregating around the lake, a contention supported also by the occurrence of nutrient-rich waters. This dry period saw reduced fires and a decline of C 3 grasses in favor of C 4 grasses. The arrival of herders in the Cape after 2000 cal yr BP is not immediately apparent in the multiple records, except for minor vegetation changes and regional fires c. 1200–1400 cal yr BP. However, a more consistent presence of livestock in the immediate area of Princessvlei occurs only after c. 600 cal yr BP, when peak frequencies of coprophilous spores coincide with changes in vegetation composition and occurrence of more eutrophic waters in the lake. The introduction of exotic flora, fire suppression, and a reduction of herding activities, characterizes the period of European settlement (c. 300 BP to present). • Multiple proxies enhance the reconstruction of environmental changes around a small lake. • Multiple proxies help define climatic changes from non-climatic disturbances on vegetation. • Critical climatic and cultural changes occurred at Princessvlei (South Africa) in the past 3.9 ka. • Native and European disturbance on vegetation and hydrology were considerably different. [ABSTRACT FROM AUTHOR]

Recreational open fires are an important and preventable cause of burn. In contrast to adults, who often sustain flame burns, children are at higher risk of thermal contact burns caused by hot embers many hours after the fire was first lit. Cases of thermal contact injury in children due to recreational fires were reviewed and the potential of a small charcoal fire to cause burns over a prolonged period was tested. Between 1993 and 2007, 67 children were admitted for treatment, with a median age of 1.6 years. Total burn surface area ranged from 0.5% to 19.5% (median 4%) with burns most commonly affecting the hands and feet. The average length of stay was 7 days and a total of 81 surgical procedures were carried out. Injury was most commonly sustained after falling into (40%), or accidentally crawling or walking on (30%), the remnants of an unextinguished fire. Small charcoal fires retain sufficient heat to cause injury at least 16h after lighting. Strategies for prevention of these injuries are outlined.