Growing beautiful forests . . . and a bonus, too

I see that at least one branch of the ‘medical’ profession is coming to its senses — silviculture. Ever since Tudor times when timber was cut down on a massive scale for ship building — our fleet being second only to the Spanish at that time but subsequently with our clippers the largest fleet in the world — and even more since then for increasing quantities needed as firewood for a growing population, pit props for deep coal mining, wooden sleepers for thousands of miles of railways and for telegraph poles, further clearance by farmers for their gigantic tractors, and yet another great surge in the 19th century for housing and fencing, our forests have become pathetic pockets, assailed further by atmospheric and fungal pollution and in turn diminishing the wild life that live in symbiosis with trees,

No wonder, therefore, with pitiably small forests, since the 1960s we have had devastations to Dutch Elm, Corsican Pine, Scots Pine, Cypress, Oak, Chestnut, Juniper, Larch, Beech, Cherry, Rowan and the current scare, Chalara Ash dieback. Living in small forest populations our trees are highly vulnerable to disease spores blown over from the continent mainly but also from Africa and North America

Prof Allan Downie, Emeritus Fellow at the John Innis Centre has searched for and identified a 200 year-old Ash tree, named “Betty”, which is resistant to Chalara. After further genetic testing, other trees have been found which have a very high or even complete resistance. So enough of them have been found and will be propagated to save the Ash. But what would happen in a few years time if another insect or virus or bacterium mutated sufficiently to produce another form of the disease — or a different disease –to which Betty and her clones were vulnerable?

And what about other trees? The chances are reasonably high that one or two among each of them, perhaps in this country or on the continent, would also have mutated sufficiently to combat their own particular killer disease. The trees would be safe but only by a hair’s breadth and in penny numbers. It would take decades to build up to former numbers.

There are really only two strategies if we really want to save beautiful variegated forests in the country. One is to have many more of them and, as often as possible, join them together in corridors. Whatever the devastation caused by one particular disease there’ll always be more than a few in any sizable forest which will have natural resistance. Any gaps that are left can be filled with a variety of other trees. The previous balance of trees may never be regained, but that is usual in the largest forests. Temporary empty areas are also the more likely opportunities for new species of trees to became established.

But for a small badly over-crowded island like Britain there’s not a lot of opportunity for growing large forests. Planting corridors between existing ones would be better until the human population is much reduced. Now that we have powerful supercomputers and good DNA sequencers there’s no reason why every tree in our forests should not be sampled. Any recurrence of a known disease would enable the vulnerable ones to be on the windward side to be cut down immediately as a ‘fire-break’ to prevent spores spreading further.

Such a database would not only be a relatively inexpensive project in order to maintain our natural woodlands. It would also be an invaluable resource when we’ll be using synthetic DNA to make exotic new carbon-based materials far superior in performance than much of the constructional steel we presently make at great expense

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