Eucalyptus Camaldulensis in South Africa – Past, Present, Future
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Transactions of the Royal Society of South Africa ISSN: 0035-919X (Print) 2154-0098 (Online) Journal homepage: https://www.tandfonline.com/loi/ttrs20 Eucalyptus camaldulensis in South Africa – past, present, future Heidi Hirsch, Michael H. Allsopp, Susan Canavan, Michael Cheek, Sjirk Geerts, Coert J. Geldenhuys, Graham Harding, Brett P. Hurley, Wayne Jones, Jan-Hendrik Keet, Hildegard Klein, Sheunesu Ruwanza, Brian W. van Wilgen, Michael J. Wingfield & David M. Richardson To cite this article: Heidi Hirsch, Michael H. Allsopp, Susan Canavan, Michael Cheek, Sjirk Geerts, Coert J. Geldenhuys, Graham Harding, Brett P. Hurley, Wayne Jones, Jan-Hendrik Keet, Hildegard Klein, Sheunesu Ruwanza, Brian W. van Wilgen, Michael J. Wingfield & David M. Richardson (2019): Eucalyptuscamaldulensis in South Africa – past, present, future, Transactions of the Royal Society of South Africa, DOI: 10.1080/0035919X.2019.1669732 To link to this article: https://doi.org/10.1080/0035919X.2019.1669732 View supplementary material Published online: 08 Nov 2019. Submit your article to this journal View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=ttrs20 Transactions of the Royal Society of South Africa, 2019 https://doi.org/10.1080/0035919X.2019.1669732 Eucalyptus camaldulensis in South Africa – past, present, future Heidi Hirsch 1*, Michael H. Allsopp2, Susan Canavan 1,3,4, Michael Cheek 5, Sjirk Geerts 6, Coert J. Geldenhuys 7,8, Graham Harding9, Brett P. Hurley 10, 11 1 12 13 Wayne Jones , Jan-Hendrik Keet , Hildegard Klein , Sheunesu Ruwanza , 1 14 1 Brian W. van Wilgen , Michael J. Wingfield & David M. Richardson 1Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Matieland 7602, South Africa, 2Honey Bee Research Section, ARC-Plant Protection Research Institute, Stellenbosch, South Africa, 3Agronomy Department, University of Florida, Gainesville, Florida 32611, USA, 4South African National Biodiversity Institute, Kirstenbosch Research Centre, Claremont, South Africa, 5Biological Invasions Directorate, South African National Biodiversity Institue, P.O. Box 52099, Berea Road, Durban 4007, South Africa, 6Centre for Invasion Biology, Department of Conservation and Marine Sciences, Cape Peninsula University of Technology, P.O. Box 652, Cape Town 8000, South Africa, 7Department of Forest and Wood Science, Stellenbosch University, Stellenbosch, South Africa, 8Forestwood cc, P.O. Box 228, La Montagne 0184, South Africa, 9Invader Plant Specialists (Pty) LTD, Durbanville, South Africa, 10Department of Zoology and Entomology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa, 11Sappi Forests Research, Planning and Nurseries, Shaw Research Centre, PO Box 473, Howick, 3290, South Africa, 12Agricultural Research Council: Plant Protection Research, Private Bag X134, Queenswood 0121, Pretoria, South Africa, 13Department of Environmental Science and Centre for Invasion Biology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa, 14Department of Genetics, Biochemistry and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa *Author for correspondence: E-mail: [email protected] 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 BACKGROUND world’s megacities (Endreny et al., 2017.Ontheother People and trees have an intimate and vital relationship (e.g. hand, many alien tree species also have negative impacts Hayman, 2003;Coderet al., 2017). It is therefore not surprising by impacting on ecosystem services or creating new ecosys- that many tree species were, and still are being, spread around tem disservices (Potgieter et al., 2017). The number of intro- the world by humans, literally following in the footprints of duced tree species recorded as invasive aliens is increasing human civilisation (Richardson, 1998). Trees are used by people rapidly several decades after widespread introductions and for multiple purposes (e.g. food, fuel, paper, timber, shelter, plantings of hundreds of tree species in many parts of the etc.) and contribute to diverse ecosystem services, including world (Richardson, 1998; Richardson and Rejmánek, 2011; net primary production, pollination, soil formation, microclimate Richardson et al., 2014;Rougetet al., 2016). provisioning, nutrient cycling, and diverse cultural services (Foli Trees are conspicuous and influential components of veg- et al., 2014;Castro-Diezet al., 2019). Trees provide ecosystem ser- etation. Because of their large size and biomass, and diverse vices worth more than $500 million per year to 10 of the features of their architecture, many tree species have a major © 2019 Royal Society of South Africa Published online 08 Nov 2019 2 Hirsch et al. Eucalyptus camaldulensis in South Africa – past, present, future 2019 influence on the structure and functioning of ecosystems intraspecific tree improvement to meet both the demands (Zalba and Villamil, 2002; Richardson et al., 2014; Rundel of climatic conditions and market requirements. In recent et al., 2014). People’s perceptions of trees and their roles in times hybrid combinations between key commercial landscapes are complex and context dependent; this means species have provided new opportunities in terms of that managing wooded landscapes is becoming increasingly growth and tolerance to both abiotic and biotic stresses. challenging in our human-dominated world (Richardson However, some niche markets and sites still dictate the use et al., 2014). In many regions, the management of trees involves of pure species where no hybrid alternatives have been dealing with conflicts of interest – where species have both developed. Six eucalypts (i.e. E. camaldulensis, E. cladocalyx, clear benefits and clear negative impacts (Kull et al., 2011; E. conferruminata, E. diversicolor, E. grandis and E. tereticornis) Dickie et al., 2014; van Wilgen and Richardson, 2014). It is are listed as invasive in South Africa by the National therefore crucial to consider both positive and negative Environmental Management: Biodiversity Act (NEM:BA; effects of non-native tree species to gain a holistic view of Act 10 of 2004; Department of Environmental Affairs, their ecology and influence when formulating sustainable South African Government). management approaches. Information on the full suite of The history of eucalypts in South Africa is very complex factors that need to be considered is very seldom available. and is closely linked to the colonisation, cultural prefer- The aim of this paper is to compile a dossier or profile of an ences, and capitalist-driven exploitation resulting from the important tree species to show the type of information that European settlement of the country (Bennett, 2010; is needed when seeking sustainable management options. Bennett and Kruger, 2015). Eucalypts are now conspicuous One of the most widely distributed and extensively planted features of landscapes in many parts of South Africa. They tree genera worldwide is Eucalyptus (family Myrtaceae; Rejmá- have diverse impacts on economic, social, and ecological nek and Richardson, 2011). Eucalyptus is the largest of the systems. Positive features of these fast-growing trees are seven genera that comprise the “eucalypts” (i.e. tribe Eucalyp- the provision of timber, paper, poles, firewood, shelter, orna- teae), with more than 700 species (Bayly, 2016). Almost all mental value, and nectar and pollen for bees (Forsyth et al., eucalypt species are native to Australia, where they are 2004;Sappi,2018). Negative impacts of eucalypts, however, iconic and conspicuous features in many landscapes and began to manifest in the early twentieth century when criti- play crucial