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Trees may be giants of our landscape but they still need careful protection

By Western Morning News  |  Posted: December 07, 2012

Comments (0) With three cases of ash-dieback now having been reported in the Westcountry, Martin Hesp has been considering the general threat seems to be escalating around our forests.

Tree disease is not a new phenomenon, we all know that, but you do wonder if we couldn't have learned more from other countries where the woodlands have been suffering far worse than ours over the past century.

Here's a story the brilliant Bill Bryson tells in his book A Walk in the Woods: "In 1904, a keeper at the Bronx Zoo in New York noticed that the zoo's handsome chestnuts had become covered in small orange cankers of an unfamiliar type.

"Within days they began to sicken and die. By the time scientists had identified the sources as an Asian fungus called Endothia Parasitica the chestnuts were dead and the fungus had escaped into the great sprawl of the Appalachians, where one tree in every four was a chestnut."

As Mr Bryson put it: "Seldom has a tree been more helpless against an invader than the American chestnut against Endothia Parasitica."

Within 35 short years, the species was completely wiped out in its homeland.

We heard this week that three isolated outbreaks of ash-dieback have been discovered in the Westcountry – one infected sapling was found near the Quantock Hills, while Devon has had two infestations, one either side of Dartmoor. Fortunately, all three cases were centred on bought-in saplings – which were instantly grubbed out and destroyed, hopefully before they could spread Chalara fraxinea to the wild woods around.

The experts believe that in each case, we should be OK – but it is also fair to say that most arboriculturists think it's only a matter of time before the vast majority of the UK's 80 million ash trees get clobbered. We can only hope that a few – estimated to be around two per cent – will have an inbuilt immunity that will allow for a future restocking of trees which are resistant to the disease.

But that's a tiny light at the end of a dark tunnel – especially when you take the thoughts of Dr Joan Webber, Head of Tree Health at the Forestry Commission, into consideration.

It was she who this week brought the nation's attention to the fact that there are 11 other deadly tree diseases "on the horizon" – saying that such pests and diseases imported into the country could wipe out both native and exotic species.

"You are not talking about hundreds of trees, but thousands and hundreds of thousands," said Dr Webber, adding: "With some of the worst organisms you are talking about millions."

Forgive me for returning to the eloquent Mr Bryson again – he happens to be so good at putting things in nutshells, if that term is applicable in this sorry matter…

"For all its mass, a tree is a remarkably delicate thing," he writes. "All of its internal life exists within three paper-thin layers of tissue, the phloem, xylem and cambium, just beneath the bark, which together form a moist sleeve around the dead heartwood. However tall it grows, a tree is just a few pounds of living cells spread between roots and leaves."

As he points out, a tree must do an awful lot of things in just these few layers – not only draw up water but manufacture lignin and cellulose, regulate the storage and production of tannin, sap, gum, oils and resins, dole out minerals and nutrients, convert starches into sugars for future use and goodness knows what else.

"Because all this is happening in such a thin layer, it also leaves the tree terribly vulnerable to invasive organisms. To combat this, trees have formed elaborate defence mechanisms. The problem arises," says Mr Bryson, "when a tree encounters an attacker for which evolution has left it unprepared."

And therein lies the rub…

We live on an island – which means we should have a better chance than most when it comes to protecting our natural woodlands. Alas, the more I write about trees and forests, the more I am beginning to realise that our arboreal industry is the poor man of agriculture.

It might sound strange to use that word in connection with woodland – but it fits because trees are plants and we grow them for reasons which either profit, or benefit, us. Often that reason is timber – where a tree really can be seen as a simple crop – but also we need our woodlands for many other vital reasons.

Combined they have a vast ability to capture the carbon we burn, they promote biodiversity, aid wildlife, and even offer us pleasant – some would say vital – places to relax in.

If you start thinking about woods and trees instead of taking them for granted (which I believe most of us do all too often), then you can very quickly come to the conclusion that they're the one bit of our countryside which we leave on a kind of autopilot.

We have a vague idea that there's this organisation called the Forestry Commission which, sort of, looks after trees – but we also know the present Government would love to give quangoes like that the chop. And we imagine there must be a few wealthy private forestry owners out there whose fate we have no interest in.

But then – when we stop and recall the bungled mess that has seen ash-dieback enter our island acres; when we hear the FC's top expert suddenly warning of all the other diseases lining up to kill our trees – we begin to see that there aren't really many folk out there standing up for trees.

The ones who are have their voices lost in a forest of other stories which overtake the headlines. Tree diseases are here today, gone tomorrow. Except they're not. And something should be done.

It would be an illogical or uncaring person who would disagree with the Woodland Trust's head of conservation Austin Brady when he says: "The Government response must be soundly based on actions that reflect evidence and experience, and must be credible in terms of really helping the situation. It would be unfortunate if the Government seeks to show its concern by choosing high profile but potentially harmful and expensive activity which delivers little in terms of reducing the spread or impact of the disease."

The Trust is now bringing together leading scientists in a bid to improve how we identify and monitor tree pests and disease in the UK – and it's also starting a programme of investing in UK tree nurseries to guarantee that all the planting stock we use in the future will be 100% from seed collected, raised and grown on in this country.

But even a proactive organisation like that admits such measures will take time – and it could be that millions of this nation's trees haven't got the luxury of phrases like "medium and long term".

Which is why the Government should be pulling out all the stops and hoisting the health of our woodlands higher up the big gnarled oak which is the national agenda. Protecting trees doesn't have to cost a lot – it does, however, need a proactive approach, and it needs it now.

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