The annual pattern of sap flow in two <i>Eucalyptus</i> species established in the vicinity of gold-mine tailings dams in central South Africa

Dye, P. J.; Clulow, Alistair D.; Prinsloo, Eric; Naiken, Vivek; Weiersbye, Isabel

doi:10.2989/20702620.2016.1207135

Cited by 4 publications

(3 citation statements)

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“…This indicates that water use is dependent on soil moisture content. It should be noted that the water use by most of the trees was within the ranges reported in literature (shown as minimum values for Eucalyptus and Searsia respectively in Figure 5) for similar studies carried out in South Africa (Dye et al, 2008;Dye et al, 2016).…”

Section: Figuresupporting

confidence: 82%

Evapotranspiration to minimise acid mine decant from a decommissioned colliery

Haagner,

van Wyk

2023

Proceedings of the International Conference on Mine Closure

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Acidic mine water decant from legacy coal mines presents significant environmental impacts to the Highveld watercourses in South Africa. The costs and logistics for active treatment are often not feasible due to the remoteness of sites, excessive capital and operational costs, lack of infrastructure and complications with brine and sludge disposal. The regulatory authorities currently prefer active pumping and desalinating water from flooded underground compartments, followed by the discharge of treated water into natural watercourses. However, if a sufficient body of monitoring evidence can prove efficacy with a high degree of confidence, then lower-cost and more sustainable water management alternatives may become a reality.In this project we monitored different tree plantation trial blocks of two species that were established in 2012 to reduce vertical groundwater recharge from rainfall that would report to underground workings. Reducing the ingress rates to below critical levels would eliminate the decant of acidic mine water to receiving watercourses.Monitoring focussed on establishing water budgets (rainfall, throughfall, soil moisture and moisture extinction, sap flow and groundwater levels) via continuous logging instruments. The monitoring period was four years, from 2018 to 2022, once the trees were nearing maturity. The data were used in building a conceptual site model and then a geohydrological model to estimate draw-down within the trial blocks. A site survey for possible plantation expansion areas followed, after which the geohydrological model was again updated to extend the ingress reduction to a larger area.The study found that trees survived very well, but that different species were better suited to specific conditions. Water uptake and ingress reduction were very effective in all but the highest rainfall periods. The geohydrological model showed effective draw-down, with the expansion model confirming that the trees could limit vertical groundwater recharge to near zero. However, a residual interflow from deeper aquifers would still result in some recharge to underground workings. During periods of excessive rainfall, this would have to be pumped and used to irrigate plantations to prevent decant altogether.The establishment of commercial-scale forestry plantations with continuous-cover harvesting could fulfil an important role for local enterprise development, job creation and effective sustainable post-mining land-use, whilst contributing significantly to continuous passive groundwater decontamination, reducing groundwater liability and environmental degradation.

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Section: Figuresupporting

confidence: 82%

Evapotranspiration to minimise acid mine decant from a decommissioned colliery

Haagner,

van Wyk

2023

Proceedings of the International Conference on Mine Closure

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“…| Glyphosate e imazapyr no controle de brotações ... 1665 que alterem a capacidade de translocação da seiva e atividade fisiológica das plantas podem afetar a translocação dos herbicidas e, consequentemente, a eficiência do controle das brotações. Dye et al (2016) observaram redução no fluxo de seiva de duas espécies de eucalipto no período de inverno, coincidente com períodos de baixa precipitação pluviométrica. Adicionalmente, os mesmos autores observaram que houve aumento das taxas de fluxo de seiva a partir do início do período chuvoso.…”

Section: Resultsunclassified

Glyphosate e imazapyr no controle de brotações de eucalipto: aplicação no fuste principal anterior ao corte da árvore

Montes¹,

Santos

Barros

et al. 2021

Ciênc. Florest.

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A pulverização de herbicidas sobre a rebrota do eucalipto é uma prática comum no setor florestal. Entretanto, observa-se a necessidade de várias operações em uma mesma área para controle das brotações. Objetivou-se avaliar a eficiência dos herbicidas glyphosate e imazapyr, aplicados no fuste principal antes do corte raso das árvores, no controle de brotações de eucalipto. Foram implantados sete tratamentos representados por doses de 3,0; 4,0 e 5,0 mL/fuste de glyphosate (Gli-Up® 360 g i.a L-1) e das doses de 0,3; 0,5 e 0,7 mL/fuste de imazapyr (Chopper Florestal® 250 g i.a. L-1), além de um tratamento-testemunha. A aplicação dos herbicidas foi realizada em inserções feitas nos fustes das árvores. Aos 30 dias após aplicação dos herbicidas, realizou-se o corte das árvores. Aos 150 dias após o corte das árvores, foram realizadas avaliações do número de brotações por cepa, número de cepas com presença de brotações, altura e a eficiência de controle das brotações. A aplicação de glyphosate promoveu redução do vigor das brotações. Porém, observou-se emissão de brotações em pelo menos 80% das cepas avaliadas. A aplicação da dose de 3 mL de glyphosate promoveu porcentagens de 80% de eficiência de controle. Contudo, observou-se que operações de controle adicionais seriam necessárias. A aplicação de imazapyr mostrou-se ineficiente com controle inferior a 25%. Portanto, conclui-se que a aplicação de glyphosate no fuste da árvore em pré-corte reduz o vigor de brotações de eucalipto. Adicionalmente, a aplicação de imazapyr, nas doses e forma de aplicação testadas, não é recomendada para controle de brotações de eucalipto.

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“…One approach seeking to reduce such impacts is phytoremediation, which uses fast-growing plants to clean the soil and water from toxic contaminants by transforming, degrading, accumulating, stabilising, immobilising, or volatising these pollutants (Lone et al, 2008). To test and apply this technique in South Africa, the Mine Woodlands Project was initiated in 2001 by the mining company AngloGold Ashanti and the University of the Witwatersrand and was active until 2016 (Dye et al, 2016). The project tested 48 indigenous according to the research subject (i.e.…”

Section: Phytoremediationmentioning

confidence: 99%

Eucalyptus camaldulensisin South Africa – past, present, future

Hirsch

Allsopp

Canavan

et al. 2019

Transactions of the Royal Society of South Africa

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Eucalyptus camaldulensis can be seen as an iconic tree of superlatives. It is the eucalypt with the widest native range, and one of the most widely planted eucalypts around the globe. In South Africa, it is the most widespread and the most aggressively invasive eucalypt. It has many uses, but also causes major impacts. However, little is known about key aspects of its ecology in South Africa, including its invasion history, invasion processes and dynamics, and people's perceptions of its positive and negative effects on ecosystems. Such knowledge is crucial for developing robust and defendable guidelines for sustainable management of the species. This paper provides a comprehensive dossier of the species in South Africa. It reviews what is known of its introduction and planting history, its current distribution, its value for commercial forestry and other uses, its impacts as an invasive species, pests and pathogens associated with the species, people's perceptions of the species and conflicts of interest, and the options for management and restoration. The review reveals that E. camaldulensis is a tree of many contradictions in South Africa, making it a poster-child example of a conflict-generating non-native species. Based on available knowledge, we assess options for improved management. We highlight several knowledge gaps which need to be addressed in more detail through future research. It is hoped that this species profile will serve as a model for the types of information that are needed for developing objective management strategies for non-native tree species in different parts of the world. Keywords: Conflicts of interest; Eucalyptus; impacts; introduction history; invasive species management; pests and diseases; tree invasions BACKGROUNDPeople and trees have an intimate and vital relationship (e.g. Hayman, 2003;Coder et al., 2017). It is therefore not surprising that many tree species were, and still are being, spread around the world by humans, literally following in the footprints of human civilisation (Richardson, 1998). Trees are used by people for multiple purposes (e.g. food, fuel, paper, timber, shelter, etc.) and contribute to diverse ecosystem services, including net primary production, pollination, soil formation, microclimate provisioning, nutrient cycling, and diverse cultural services (Foli et al., 2014; Castro-Diez et al., 2019). Trees provide ecosystem services worth more than $500 million per year to 10 of the world's megacities (Endreny et al., 2017. On the other hand, many alien tree species also have negative impacts by impacting on ecosystem services or creating new ecosystem disservices (Potgieter et al., 2017). The number of introduced tree species recorded as invasive aliens is increasing rapidly several decades after widespread introductions and plantings of hundreds of tree species in many parts of the world (Richardson, 1998;Richardson and Rejmánek, 2011;Richardson et al., 2014; Rouget et al., 2016).Trees are conspicuous and influential components of vegetation. Because of the...

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The annual pattern of sap flow in two Eucalyptus species established in the vicinity of gold-mine tailings dams in central South Africa

Cited by 4 publications

References 10 publications

Evapotranspiration to minimise acid mine decant from a decommissioned colliery

Evapotranspiration to minimise acid mine decant from a decommissioned colliery

Glyphosate e imazapyr no controle de brotações de eucalipto: aplicação no fuste principal anterior ao corte da árvore

Eucalyptus camaldulensisin South Africa – past, present, future

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