The mighty ash, tree of materials, mythology and medicine

Ash by Edward Parker 2021. Reaktion Books Ltd

Spoiler Alert! (and Summary?)

Edward Parker’s Ash [which book is here appraised] is a title in Reaktion Books’ Botanical series. Having read any of my previous views on books in this collection (e.g. here, here, and here), you will know that that information is really all you need to know about the book. And should also be all the encouragement you need to go and buy it, or – at the least! – to read it. Nevertheless, recognising that some of you might like, or need, a little more detail before being persuaded, please read on…

Utilitarian ash

Before reading Ash, one of the few things I know about this tree is that its wood burns well when ‘green’. Which is good to know, if you are in need of additional warmth, know what ash looks like, have the necessary tinder to start off your conflagration, and have the wherewithal to make a flame in the first place. But, there’s much more to ash than that heart-warming nugget of survivalist information [and, yes, Parker deals with the green ash issue early on, in passing, on p. 10 – and in more detail on p. 136]. And you’ll discover a lot about the ways humans have exploited the tree in Chapter 4. Indeed, so useful has this tree been to humanity that Parker is moved to state: “Its [ash’s] timber, leaves, sap and bark have been used by people for thousands of years. Its timber is particularly versatile, providing much of the material crucial to the development of warfare, transport and settled agriculture” (p. 114). Elsewhere, we read that: “despite their rather unremarkable, almost generic appearance, few trees have had such an impact on the development of human civilization over the last 5,000 years as the ash tree” (p. 8). This is a bold claim, but is it justified? Certainly, Parker does a very good job in trying to convince you of the truth of that statement throughout the book. And this reviewer is almost persuaded of the potential primacy of Fraxinus. Almost. However, I think that Birch (another title in Reaktion Books’ Botany series by Anna Lewington) just wins out over ash in that regard. But, you are invited to make up your own minds, by reading Parker’s book.

Ash under threat

The other thing I knew was that ash trees were having a very hard time with the fungal disease known as Chalara ash dieback. That existential threat to the tree is dealt with in Chapter 2 – along with the unwelcome news that it could be worse than the infamous Dutch elm disease epidemic of the 1980s in which 30 million elm trees were lost from the British landscape. Furthermore, ash is also under substantial attack in North America from the unwanted attentions of the insect known as EAB, the emerald ash borer. To date, that invertebrate invader has caused the death of an estimated 50 – 100 million ash trees in North America (and EAB is now present in Europe…). These current and future biological threats to ash trees are considered at some length in Parker’s book – as are several other biological and non-biological dangers. Consideration of those various threats also gives a good idea of the fragility of ecosystems in which ash trees play a major part. For instance, we are told that ash is a key species for land snail diversity, and a home and haven to threatened bryophytes,* and lichens. But what was completely new to me was news of a simple method of preventing chalara, which consists of dipping exposed ash seedling roots in hot water for several minutes. This seemingly drastic temperature treatment kills the fungus but the seedling survives. Sadly, no source is cited for this intriguing ‘fact’,** which is easily overlooked because it’s only mentioned on the antepenultimate page of the book, and not at all in the chapter that deals specifically with threats to the ash. Despite that hopeful discovery, there seems to be little long-term good news about this tree, which has prompted Parker to open Chapter 3 with the rather depressing statement: “Ash trees around the world today are dying at an unprecedented rate, in what could eventually be cited as one of the great tree extinctions of human times. One of the biggest threats to ash trees in particular, and global biodiversity in general, is the accidental introduction of non-indigenous, invasive pests and pathogens” (p. 63). It would seem that the demise of the ash can be cited as a crime by humanity against humanity.

The best is yet to come?

Undoubtedly, trees have played a very important role in the history of humankind, or, as Parker puts it: “Trees have provided a number of key global resources that have enabled people to survive, thrive and develop from prehistoric times to the Industrial Revolution and beyond. They have provided food, medicines and wood from which it was possible to make fire, shelter and a wide range of tools, weapons and other products” (p. 113). And, “It could be argued that without the ability to manage and harvest useful materials from trees, many of the advances towards civilization as we now know it would have suffered” (p. 113). But, as with other plants with historically great utility for humanity, many of the more materialistic traditional uses of trees are increasingly being replaced by alternative materials (e.g. here, here, and here). However, although particular practical usefulness of plants may be waning in the 21^st century, we are in the midst of a new golden age of resourcefulness of trees as we reconsider their potential as sources of compounds of medicinal value (e.g. here, and here) – as we are doing with other plants (here, and here) (Biljana Bauer Petrovska, Historical review of medicinal plants’ usage, Pharmacogn Rev. 6(11): 1–5, 2012; doi: 10.4103/0973-7847.95849). Those aspects of ash ethnobotany are considered in the book’s final chapter, which covers such topics as the role of ash in countering snake bite, in dealing with obesity, and the pharmaceutical potential of manna, a white exudate from Fraxinus ornus (the manna ash) and F. angustifolia (narrow-leaved ash). Largely comprised of mannite (or manna sugar), manna is sweet to the taste and has been used by humans for thousands of years as an emergency food source. Commercially manna is used to make a sugar alternative, mannitol, which is not only suitable for diabetics, but also has promise in the treatment of ‘brain conditions’ such as Parkinson’s and Alzheimer’s. So, although the Parker-posited previous peak of ash’s usefulness to mankind may have been the 17^th century, maybe there will be another peak in the not-too-distant future as ash – and other plants – are re-evaluated for their medicinal potential. That may yet be the most enduring of ash’s usefulness to humans.

And a reminder of ancient anthropological ash associations…

Because Ash is very much a plants-and-people tome, there are a lot of interesting insights into the more mythological associations of the tree. Parker has quite a lot to tell us about the use of the concept of giant trees as metaphors for the structure of universe in the belief systems of many ancient peoples. One of the most famous of these icons is Yggdrasil, the ‘guardian tree’ that looms large in Germanic, Norse and Celtic mythology. Considered to be an eternally green ash tree, this view of Yggdrasil nicely fits in with a book devoted to the ash. However, Parker generously includes due mention of the contrary view of others – such as Fred Hageneder (who wrote Reaktion Books’ Botany title Yew) – that Yggdrasil might be a yew instead. Although Parker is firmly of the point of view that it’s an ash – and duly defends that interpretation in his book – it is good to see this sort of balance and intellectual honesty demonstrated. All of Chapter 3 on mythology, which also includes the notion that the ash tree is the progenitor of mankind in several ancient cultures, is fascinating. And such insights underline the fact that plants have utility far beyond the physical needs of people, they have strong associations with our spiritual lives as well.

Overview

Ash contains an Introduction, an Epilogue, and 5 Chapters with straightforward titles, such as The botany of Fraxinus [the ash tree genus, and which first chapter gives a pretty good summary of ash biology and ecology], The mythology of ash, and The healing ash, which simple, but effective, ‘sign-posting’ leaves little doubt about the chapter’s content. On the whole, Ash is well-written, and Parker is an enthusiastic advocate for his subject. Several technical terms are used in the book and generally are either explained in the text, or included in the 3.5 pages of the Glossary. The customary Reaktion Books’ Botanical series Timeline in Ash starts 500 millions of years ago with appearance of the first land plants (which is reasonable since ash is a land plant), but ends in 2017 – and rather bizarrely in a book devoted to the ash – with the statement that the rose was the most important and influential plant of the last 50 years. Ash is generally well-evidenced: Within-text super-scripted numbers are gathered by Chapter at the end of book in almost 12 pages of a References section that give details of the sources used. And there’s an extra page of Further Reading; but, since at least some of the items included there have already been cited separately as sources in the References section, the purpose of that list isn’t clear to this reader. However, more references are need in several places in the book, e.g. pp. 115, 116, 126, 152, and 153, to give the necessary evidence for statements made. So, although Ash’s evidence-based credentials are pretty good overall, they can be improved. As is typical of a Botanical Series book, Ash is extremely well illustrated throughout, and more often than not those images add to the text. But, it’s not clear how the photograph captioned “A young girl listens to the internal sounds of a wired-up ash tree” (p. 182) helps us to understand the illustration; no context is provided in the text to explain the image, and no source is supplied for further information. The book’s high production values are underlined by the evident attention paid to proof-reading the text; I only found one ‘typo’ – ‘aand’ on p. 103 in the phrase “heroes aand ancestors”.

Summary

The quibbles noted above notwithstanding, Ash by Edward Parker is a fascinating, fact- and photo-filled Fraxinus feast, and proudly stands tall amongst Reaktion Books’ other tree – and tree-like – titles such as Birch, Palm, and Mulberry. And it’s another useful addition to the plants-and-people literature.

* Somewhat confusingly, Parker’s phrasing on p. 69 is: “threatened bryophytes (ferns) and lichens¹⁶”. Used in this way it indicates that Parker considers ‘ferns’ to be a synonym for ‘bryophytes’. But, the two words do not mean the same thing; although both terms refer to members of the Plant Kingdom, ferns are quite different plants to bryophytes (which broad-brush botanical term is a collective noun for mosses, liverworts and hornworts). We are therefore left to wonder if ash is important to ferns or to threatened bryophytes, and aren’t helped by the source that Parker associates with that statement by way of in-text Note No. 16. The reference for that Note is the Joint Nature Conservation Committee Report No. 483 by RJ Mitchell et al. (‘The Potential Ecological Impact of Ash Dieback in the UK’), but it’s only pages 157-158 (Section 17.2) – which deals specifically with lichens – that is actually cited. However, having checked the report, I do note that pages 158-159 (Section 17.3) deal with bryophytes, and the species mentioned therein appear to be bryophyte taxa not ferns (which latter plants are mentioned elsewhere in the JNCC publication). Use of the bracketed term ‘fern’ by Parker on p. 69 of Ash should therefore be disregarded; at best it’s incorrect, at worst it’s misleading. The equivalence of terms that Parker makes on p. 58 in his phrase “bryophytes (mosses and ferns)” also needs to be corrected, most simply by deleting ‘and ferns’. Interestingly, item 17 of that JNCC’s Report’s Summary includes this piece of text “Nine bryophytes (mosses, liverworts and hornworts)”, which shows correct synonymy for the term ‘bryophytes’.

** Disappointed not to have a source for this encouraging news of a Chalara treatment, a quick bit of Googling unearths Tine Hauptman et al’s “Temperature effect on Chalara fraxinea: Heat treatment of saplings as a possible disease control method” (Forest Pathology 43: 360-370, 2013; doi: 10.1111/efp.12038), which is relevant to the statement in Parker’s book. Matters have moved on taxonomically since that 2013 paper and Hymenoscyphus pseudoalbidus should be the name that’s used for the pathogen responsible for ash dieback – and this is noted in Ash.