Plant Cuttings

You’ll probably have noticed that no sources – apart from one to the publisher’s site for the book – were included in my appraisal of Rare trees by Oldfield & Rivers. That is not how I like to work, but was done deliberately, to emphasise how frustrating it is not to have evidence to support factual statements that had been made. To show the contrast, and what one of my appraisals should look like, this post is a ‘revised’ version of that appraisal, with sources supplied for statements of fact, etc. I do hope this more source-stated version is appreciated.

Rare trees: The fascinating stories of the world’s most threatened species by Sara Oldfield and Malin Rivers, 2023. Timber Press.

“Goats on a Argan (Argania spinosa) in Morocco” by Marco Angeli, file licensed under the Creative Commons Attribution 2.0 Generic license.

Rare trees by Sara Oldfield & Malin Rivers [which title is here appraised] is a bittersweet book. Bitter because it catalogues the threats caused to trees globally by many factors, but which are often caused by human activities. But, somewhat sweetened because it offers some optimism that all is not doom-and-gloom for trees and forests by documenting the many projects and initiatives undertaken by individuals, groups, and governments around the world that are helping to conserve our threatened trees and forests. So much for a summary of the book. Let’s put some flesh on those bare bones. And, to shake this appraisal up a bit, let’s start with the index.

Indicative content

The book’s Index occupies approx. 12 pages of 3-columned entries, from Abies to Zoological Society of London. But an Index does more than tell you the pages upon which various terms, etc. can be found, it is also a great way to get a feel for the content of the book. In that vein, I present the following observations about the index’s entries, which include: Blackhall-Miles, Robbie [many people are name-checked and quoted throughout the book, and their important contributions to tree conservation celebrated]; cattle farming [one of the most common threats to forests and trees]; Dashman Nature Reserve [Rare trees contains lots of mentions of protected areas]; Ebony Project [many conservation initiatives are covered]; Fairylake Botanic Garden [the important role of botanic gardens globally in ex situ conservation is underlined throughout the book]; gutta-percha [the book has lots of references to the utility of trees – a whole chapter no less]; hornbeam [the text uses scientific and common names of trees – although the latter are primarily the English names, several local language names are included]; Indonesia [many nations are name-checked and their tree diversity – and conservation initiatives – discussed]; jewel beetle (Kathy Keetley Garvey) [it’s not only trees that the book mentions – in this instance the insect is better known as the emerald ash borer that’s a significant threat to ash trees (Ben Jump); Kayapo people (Jill Langlois)[several indigenous groups are included because they are often best placed to undertake necessary conservation measures – and tend to have more respect for the forest than city-dwellers]; Liquidambar [genera and species names are included]; Millennium Seed Bank [such sites are also important in the tree conservation story – but curious that the Svalbard Global Seed Vault was not mentioned…]; non-timber forest products (NTFPs)(Malcolm Gore) [an important reminder that it’s not just timber that humans exploit from trees]; Oldfield, Sara [this author is quoted in the text re the Global Tree Campaign]; Philip II, King of Spain [appropriate historical aspects of tree stories are mentioned – in this instance it refers to the first attempt to regulate the trade in brazilwood; quinine (Jane Achan et al., Malar J 10: 144 (2011); https://doi.org/10.1186/1475-2875-10-144) [many tree species provide valuable medicines]; rock gnome lichen [which non-tree species is endangered by the demise of the Fraser fir forest (Steve Nix; Patti Weeks), reminding us the trees are not isolated individuals but part of a community of living things]; Sapotaceae [a family that has a section devoted to its trees in Chapter 3]; tuberculosis [which condition has been treated with the quiver tree by the San people of southern Africa – and an important reminder of the ethnobotanical value of trees and tree products]; United Nations Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) [a reminder that legislation does exist to try and prevent over-exploitation of endangered trees and their products]; Virginia pennywort (Matt Candeias) [the roots of which plant were mixed with animal fat and extracts of American sweetgum and used to treat wounds, bruises, and ulcers – another ethnodendrobotanical reminder]; Wollemia nobilis [evidence that rare trees are still to be found in the wild]; Xantolis tomentosa [some trees are apparently only shown in a photograph, without additional text elsewhere in the book…]; Yosemite Bill [not an ‘old-timer’ from the Yosemite Valley, but reference to legislation making that region of the USA a state park in 1864]; Zelkova sicula [mentioned so that we have an entry for all 26 letters of the English alphabet (Philippa Steele) – which I always find satisfying, plus, it’s always nice to have a book about trees that does go from Abies to Zelkova…].

For completeness, just before the Index we have: a single page of Resources [providing websites of 25 relevant organisations, e.g. Bonn Challenge, Botanic Gardens Conservation International (BGCI), Global Tree Assessment, IUCN Red List of Threatened Species, and World Flora Online]; Acknowledgements [a single page which, although saying nothing specifically about sources of factual statements made, does tell us that Peter Wilkie wrote the Sapotaceae account, and Adrian Newton contributed the section on tropical cloud forests – both of whom are named as contributors on p. 3]; and approx. two pages of 3-columned listing of sources of photographs included in the book [Rare trees is lavishly illustrated with often full-page colour photographs*]. Lastly, and after the Index, we have a photograph and a paragraph of biography about each of the two authors.

The main text of the book

– of almost 380 pages – consists of an Introduction, three Chapters, and an Epilogue, which sections’ contents can be summarised as follows.

Introduction

Right at the start of this section we are told that Rare trees “celebrates the global diversity of trees. It shows the threats now leading to extinction of trees around the world, … and highlights the actions that are being taken to conserve the trees in most serious trouble” (p. 6). Having read through the book, I’m happy to say that this is what it does. It’s always nice to see a book delivering what it sets out to do.

As you should expect from such a section it provides an introduction – and a particularly thorough one – to organisations, themes and concepts developed more fully in the chapters that follow. Consequently, here we have an account of the global threats to trees [spoiler alert: globally, the main threat is habitat destruction, wrought by humans]; a historical background to tree conservation work, with mention of the Global Tree Campaign and the Global Tree Assessment; a reminder that although 1976’s CITES was one of the first international agreements, its implementation is primarily via national legislation and enforcement; if completed, the proposed 8000 km long Great Green Wall of trees will be the largest living structure on the planet; concepts of in situ and ex situ conservation are explained and discussed; a sobering statement that “Much of the world’s forest land, with some of the richest tree diversity, lacks formal protection” (p. 16) is made; roles of the Forest Stewardship Council (FSC) for timber, and the non-timber forest products’ equivalent, FairWild Standard, are included; an important caveat of the usefulness of tree-planting [which needs to be the right tree in the right place, and ideally the right mix of species]**; and we are introduced to the Bonn Challenge. In doing its scene-setting, a lot of initialisms, which are used in subsequent chapters, are introduced. Although they are presented in full on first mention here, a glossary would have helped readers to be reminded of their meanings when encountering them elsewhere in the book.

Chapter 1: Trees and their ecosystems

In its 45 pages or so, this chapter provides a round-up of the characteristics of different forest areas: tropical rainforests; tropical cloud forests [although the figure on pages 36 and 37 entitled “Distribution of tropical montane cloud forest around the world” appears devoid of any interpretation or supporting narrative in the text to help the reader understand what it shows, e.g. what does ‘Relative Occurrence Rate p(x/Y = 1)’ mean?]; tropical dry forests; temperate and boreal forests (which includes temperate rainforests…); and islands. A chapter full of good tree-biased ecology and geography.

Chapter 2: Trees and their uses

This was my favourite part of the book. In approx. 100 pages it covers selected aspects of the human uses of trees, featuring sections devoted to: Medicines, poisons, and perfumes [apparently, “An estimated 6000 tree species have some medicinal or aromatic use” (p. 71)]; Precious timbers and music woods; Fruit and nut trees; and Ornamental trees. New to me was news of the “Mahogany is murder” campaign run by Friends of the Earth in 1992. Overall, this chapter provides a round-up of tree-focussed ethnobotany and insights into conservation and preservation practices that attempt to maintain the existence of trees’ valuable resources and comments on sustainable forestry. Beginning with this opening statement that: “Products from tree species are woven into our lives in myriad ways. Many of these products, however, cannot yet be made from cultivated trees or with artificially synthesised replacements” (p. 70), this chapter makes for a pretty powerful argument for the need to conserve these incredible organisms.

Chapter 3: Special tree groups

Approx. 200 pages highlighting the problems faced by – and the conservation potential for – selected groups of trees, some whole families and several genera [although the reasons for the choice is not clear]. Those ‘special’ tree groups are: Conifers (James Emory Eckenwalder) [so, it’s not just flowering plants that are covered in the book, and 21 species of these gymnosperms are considered in detail; “Sadly, over one-third of all conifer species are threatened” (p. 173)]; Magnolias [“Nearly half the world’s Magnolia species are threatened with extinction, and one-third are still too poorly known to make a conservation assessment” (p. 247)]; Ashes (Vanessa Myers) [species within the genus Fraxinus]; Oaks [Quercus species]; Dipterocarps [although a big group of endangered trees, only one species considered in detail]; Palms [monocots as well as eudicots and magnoliids amongst the angiosperms are covered]; and Sapotaceae [“887 [of around 1300] Sapotaceae species have an IUCN Red List assessment” (p. 359)].

In addition to more general information about the groups highlighted in this chapter, 52 species from those categories are ‘showcased’ in narrative text and with a summary display. Those species displays, headed-up with a global distribution map, list: IUCN red list category [although many are listed as vulnerable, critical, and endangered, several are described as being of ‘least concern’, which is rather at odds with the title of the book; Rare trees is not just about rare trees……]; Natural range [now in many cases extended via translocation across the globe, and due to ex situ planting in botanic gardens, etc.]; Preferred habitat [showing just how specialist and rare some of the tree’s ‘homes’ are]; and Threats [which include: severe population fragmentation; logging; livestock farming and ranching; urbanization; shifting habitat due to climate change; genetic crossbreeding re giant redwood; rubbing by deer; war, civil unrest, and military exercises; open bauxite mining; leaves harvested for thatching; trunks used for cooking fires, shelters by miners; palm heart trade [which products we are told “feature in millionaire salad” (Laura Frankel)(p. 353)]]; and unsustainable leaf harvest for tourism]. In summary, a lot of those threats can be classified as ’competition’ between trees and humans and their activities – which includes climate change. 

Chapter 3 contained many interesting facts, which added to my own understanding of tree diversity and biology. For example, only about half of palm family’s 2600 species are trees (p. 323); oak is the national tree of 15 European nations, and of the USA (p. 282); Mexico has the greatest oak diversity of any country with c. 160 native species (p. 291); the connection between gutta-percha – latex product from sapotacean species Palaquium gutta – and insulation of deep sea telegraph cables (p. 363), and the notion of ‘slaughter tapping’ (p. 363). All of which will be usable in my own writing – when suitably source-stated [see Why, no sources?!? section]. 

Epilogue: How you can contribute to a future for all trees

Even though “Thirty percent of all tree species are threatened with extinction” (p. 379), this section does offer some optimism [whilst repeating the caution regarding tree-planting schemes already stated in the Introduction]. In keeping with this section’s title, it lists 13 ways (in a graphic on p. 383) that individuals can help to save trees from extinction. Although this section is a bit down-beat, it is nice to end the book on a sort of ‘positive’. 

What, no sources?!?

In terms of content and overall message, Rare trees is a great book. My only real criticism is the book’s complete absence of any sources, nor even any acknowledgment that at least some of the information in the book has come from the work of people other than the authors, and the two contributors. That really isn’t good enough. Although both Sara Oldfield and Malin Rivers have many years’ experience and expertise in roles related to the subject matter of the book [e.g. the authors’ biographies tell us that Oldfield is Co-Chair of the IUCN/SSC Global Tree Specialist Group, responsible for promoting and implementing projects to identify and protect globally red-listed tree species, and Malin manages the red list programme at BGCI, with its current focus on the Global Tree Assessment], I doubt that they’ve generated all of the book’s facts. For example, within the first three pages of the book’s text we have the following unsourced statements: “trees provide habitat for over 50 percent of terrestrial biodiversity, including 75 percent of birds and 68 percent of mammals” (p. 6); “In total, there are over 58,000 tree species around the world” (p. 7); “Trees first evolved over 300 million years ago” (p. 7); and “Over 17,500 trees [presumably that’s species of trees rather than individual trees…] are threatened with extinction” (p. 9). True, the book contains a lot of quotes from, and information attributed to, named individuals. Although such commentary is important in emphasising the involvement of people in trying to save/preserve/conserve/reintroduce these amazing natural wonders, it’s not the same as – and cannot be a substitute for – evidence-based, source-stated facts that the reader can consult. 

Summary

Apart from its major deficiency, this is a great book if you want to know about the resource value of trees and tree products and the ecology and conservation status of forests and trees. Rare trees by OIdfield and Rivers is definitely one to add to your reading list. And, considering its important chapter on the uses of trees, it is also a welcome addition to the plants-and-people literature.

* One reason this is a rare book about trees is that it may contain the only account of the argan tree (Sideroxylon spinosum, synonym Argania spinosa) that doesn’t illustrate it with a picture of goats perched precariously amongst its branches high above the ground. For suitably capricornified accounts of this iconic tree, see here, here, and Marc Silver.

** There’s been a flurry of articles related to tree-planting that are appropriate to mention in this item. Accordingly, for more on this topic, see David Hill, Emmanuel Igunza, Sneha Johari, Caroline Kimeu, and Perrine Mouterde. And, for more on the role that trees can play in tackling the climate emergency, see James Dinneen, Catrin Einhorn, Amanda Gokee, and Johnny Wood. For news of an approach to mapping forests that uses artificial intelligence (AI) (Bernard Marr), see the article by Lucinda Cameron. And, finally, for a report that looks at the effects of climate change on the fate of an iconic tree of the American Pacific Northwest forests, see Nathan Gilles.