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HEADLINE: “THE GREAT CHESTNUT TREES OF EUROPE ARE DYING”

ARAB NEWS, 6th September 2012 (syndicated from Associated Press)

Ever since I was a child in England I have loved conker trees.

I don’t suppose it’s still true in these multi media days, but for lads (and sometimes lasses) of my generation the conker tree was instantly recognized, and in the summer months we passed the time watching conkers grow and trying to coax them from the tree long before those wonderful shining chestnut orbs were fit for combat. I can still remember the joy of summer car journeys interrupted in Dorset lanes so that I could linger for a while to scoop, hook or knock the playground currency from the lumbering bent boughs of the mighty chestnut trees. Later we would pickle them for strength, leaving them in dark dusty jars in the garage for the winter. Of course they were long forgotten by spring. Presumably patient fathers quietly disposed of them while we sat at school desks, or watched Blue Peter on dark chilly spring evenings.

summer quarry

The horse chestnut, Aesculus hippocastanum, is a striking tree. Across Europe it’s a stately favorite in parks and large gardens. In England it was introduced in the late sixteenth century, and by the eighteenth century it was a popular feature as part of the man-made landscape in the parklands of country estates, and also to mark the boundaries of larger properties. It can grow to nearly 40 metres, a large tree by english standards, which once mature sends huge drooping boughs towards the ground for children to swing and climb.

under the greenwood tree

In May its bright white flowers, in the form of panicles up to a foot in length, lift english spirits with early thoughts of summer, and bucolic reminiscences of country cricket matches and cattle ruminating in its shade. It has become part of the very myth of Englishness. As an urban feature its smaller cultivar, the Red Horsechestnut (Aesculus × carnea: crossed with a Red Buckeye, Aesculus pavia) decorates city streets with similar, but red, panicles. This tree is particularly popular in Germany, where it’s been a feature for nearly 200 years. I remember it brightening many business trips to Frankfurt in the 1990s.

red chestnut blossom

The horse chestnut is a foreigner to England, and to most of Europe. It’s a native of the Southern Balkans – Albania, Macedonia and Northern Greece – but its popularity has carried it across the temperate world in the last three hundred years. Although a fairly useless tree in economic and domestic terms (the conkers are slightly poisonous and cause sickness both to people and horses if eaten) the beauty of its form and flowers has sent it far and wide as a shade giver and eye-catcher. In England, at least, it doesn’t easily self propagate, and its height and bulk make it unsuitable for smaller gardens and restricted urban spaces. (Hence the use of the smaller red cultivar in German streets). As I know from personal experience it is relatively easy to grow from the conker, but much more difficult to find good homes for it once it reaches its flower pot limits.

For several years now I’ve noticed how early the chestnut leaves turn brown and shrivel – often by mid July in England. I’ve been compelled to share these observations with my long suffering and (understandably) tree-deaf family, and I had wrongly assumed that Aesculus hippocastanum was an early faller. I had obviously forgotten my long summer holidays seeking the (too young) shining orbs under deep green foliage.

But now, courtesy of Arab News – not usually a source for tree updates – I’ve been shown the error of my assumptions. Those beloved conker trees are under attack from two different aggressors: the leaf mining moth, Cameraria ohridella, whose larvae feed on its leaves; and a nasty bacterium called Pseudomonas syringae pv. aesculi which causes a disfigurement (and ultimately death) by “bleeding canker”.

The moth was first observed in Macedonia in 1984 but apparently took 18 years to reach England – presumably assisted by the increasingly global inter-connectedness of human activity. By destroying its leaves so early the moth robs the tree of essential sunlight time during the summer months, and may also make it more susceptible to the the second attacker.  A UK Forestry Commission survey of the bleeding canker conducted in 2007 concluded that ” All regions [sampled] had some symptomatic trees and overall, 44% of the trees inspected in the rural environment and 55% of the urban trees displayed symptoms of the disease… The level of symptomatic trees were (sic) especially high in south east England”.

I do not know what, if anything, can be done, or is being done, to save the horse chestnut. A BBC web-page offers this rather forlorn long term advice: “General advice includes trying to plant trees of local provenance, as research shows that specimens grown from local seed stock are best adapted to local conditions, and have a better resistance to pests and diseases”.

The accountant in me knows that cash-strapped Europeans have more important priorities right now than saving a few useless conker trees. Ironically, a Western Europe without this beautiful traveller would – in a purely technical sense – be a more natural landscape than one which is dotted with foreign imports.

But somewhere deep within me the child and poet pushes the accountant aside. How could we not lament the passing of these beautiful and iconic trees?

Bizarre mangrove world,

litorally most hostile

oozing odd objects.

Pneumataphores gasp,

anaerobic soils rinsed by

anoxic water.

Strange life forms beckon.

Viviparous propagules

seeking distant soils.

 
This weekend I had some business in Abu Dhabi, so I took the opportunity to find out a little more about the city of excess. It proved to be a great weekend for UNLEARNING*.  Forty-eight hours are not enough to claim that I know much – either about Abu Dhabi or about mangrove trees – but here are some  things I unlearned this weekend. Maybe you too will unlearn one or two items…
…and I’ve even thrown in some haikus as part of a desperate attempt to bump up my readership.
 
1. Abu Dhabi is not just about excess.
OK – it is mostly about excess: among the wealthiest per capita nations; highest per capita water consumption; fastest roller-coaster; most leaning building; etc, etc.

Abu Dhabi – a little off balance?

But in amongst those adolescent “look at me” gestures, there are some quieter, saner, activities to be applauded, and one of these is the emirate’s real efforts to protect and develop its mangrove ecosystem. And if you look carefully, in among the mangroves, you may spot a few brightly colored kayaks quietly conveying tourists like me to the edge of a strange alien world. As of last Thursday I can personally recommend the Noukhada Adventure Company if you are planning a trip. A fantastic introduction to mangrove magic, and a great antidote to the city of excess.

[“helping to develop eco-tourism for Abu Dhabi and the UAE through kayaking, sailing, blokarting and trail biking” – www.http://noukhada.ae/%5D .

a peaceful, low impact, interaction

 
2. Not all mangroves live in swamps
My second unlearning of the day was that the words “mangrove” and “swamp” are not inextricably linked, as they seem to have been in my mind since childhood. Not all mangroves live in swamps, and not all swamps are hosts to mangroves. For some reason I always associate mangroves with (a) swamps, and hence (b) mosquitoes, and (c) crocodiles. I’m delighted to report that on Thursday I experienced mangroves up close and personal without even a whisper of swamp, mosquito or crocodile. And now I know that the correct term for the mangrove ecosystem is “mangal”. But take care! This word can also mean a Turkish barbecue, a Pushtun tribe, a Hindi font or a Bulgarian gypsy.
 

Mangal magic

 
3. There is no such thing as a “mangrove tree”.
(Less technically minded readers or those with an aversion to Latin may choose to skip this section)
This half truth surprised me. Unlike oaks, which all belong to the genus Quercus, or willows (Salix), “mangrove” is a term for many different families and genera. Like many tree “facts”, no-one seems entirely sure about the exact numbers. Estimates range from 7 (Guyana mangrove restoration project) to 110 species (Wikipedia) with a consensus vaguely discernible at around 60 to 70 species. We’ll keep it simple and colorful by mentioning just three main genera: Avicennia (9 species? – including the black and grey mangroves);  Rhizophora (8 species? – including the red mangrove, with the delicious name Rhizophora mangle); and Laguncularia (10 species? – but not all are mangroves – including the white mangrove, Laguncularia racemosa).
So – as you can see – all generalizations about mangroves should be taken with a large pinch of the salt which the grey mangrove, Avicennia marina, excretes from its leaves.

grey mangrove tears

 
4. The mangal is not useless marginal territory waiting to be put to better use by enterprising capital
If I had time, and you had the reading patience, I could fill another post completely on this topic. But I have zero credentials as an eco-warrior, so I’ll be brief. Sadly, it’s a common enough story of the early twenty first century: a natural resource, misunderstood, under-estimated, used and abused in the last century (in this case, mainly abused) and only slowly revealing its true value. Mangal has been described as the “supermarket of the sea” for its superior protection for the young of many, many forms of sea-life (think Nemo in the sea anenomes, but without all that garish Disney color). I’m reliably informed that it also boasts very high levels of carbon sequestration compared to terrestrial trees; and that its value as a tsunami-break (slowing and diffusing the power of the wave) is more and more recognized. In the Americas there is a growing conflict between shrimp farmers and those who recognize the true value of the mangal.  You can read about it in “Let Them Eat Shrimp: The Tragic Disappearance of the Rainforests of the Sea” by Kennedy Warne [Island Press, 2011].
 
So I hope  I’ve given you a taster for what I think is a little known and even less appreciated world of the mangal. There are many other wonderful oddities I’m only just beginning to understand. For example: the red mangrove has evolved a fantastic propagation technique called a “viviparous propagule” which germinates into a miniature tree while still attached to its parent, and behaves like a fishing float after it falls to the water, righting itself at auspicious moments to search for a suitable anchor site.
But I fear, kind readers, that even those few of you who have stuck with me this far may now  find your attention wandering like the propagule, looking for a new place to plant your attention…
 
One final comment on Abu Dhabi, and one thing I did not manage to unlearn, even after a personal visit, was just how extravagant is the Emirates Palace Hotel (of the “World’s most expensive Christmas tree” fame).

the house of bling

 

bling, bling… ka-ching

 I’m sure there is good to be found even here, but I decided to look elsewhere…  
 
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Have you unlearned* anything valuable this week?        
 
 
  
* UNLEARNING – the healthy habit of re-visiting all those cherished prejudices and preconceptions which we use to get through the day without constant overload. Regular unlearning should, in my humble opinion, be mandatory for all over 25 year olds, but since this blog is for sharing, not preaching, I’m relegating this thought to a footnote.