12 November 2014

The recent news that we have a disease capable of decimating ash trees is very concerning. The Chalara fraxinus fungus has been found in East Anglia, but planted trees have also been destroyed in Scotland and all imports of ash timber have been banned.
Ash in planted woodlandWebAsh is one of our most common broadleaved native trees. You rarely see whole stands of it, but it is an important component of mixed woodland, especially on base rich fertile soils. It is well distributed in Highland Perthshire, is commonly planted in new farm woodland schemes, and is one of those species that will continually try and grow in your flower beds if you let it. It is a large tree, it coppices well, it produces valuable sawn timber as well as good firewood, and it grows quickly. In Britain as a whole, it is the third most widely occurring broadleaf after oak and beech, but as a non-woodland tree (small clumps, isolated trees and linear features), it is our most common broadleaf species, mainly on the strength of the number of trees in the smaller diameter age classes.
We already have a type of “ash dieback” in Britain, which has been present for 60 years or so, but that tends to only affect isolated trees, and is not a serious problem at a national level. We have a similar problem with alders, but again, this is at a low level, and does not threaten the species as a whole, or habitats composed of it.
If this new disease only operates at that level, then we will be OK, it only being a nuisance that we have to try and work around. However, it appears to be a lot more aggressive than this, with over ninety percent of trees in Denmark being killed by it. If that happens here, then we have a big problem. We have already seen in the 1970’s what Dutch Elm disease can do to a native tree species. It is still endemic today, and we dare not plant elm in anything more than small quantities, and only then if we are prepared to lose them. Elm survives as a component of our mixed woodland habitats, but it is too high risk to plant it on any scale, or as a timber species. Ash is about four times more common. That is the order of magnitude of the potential problem.
Open Grown AshWebIf it was just ash trees, that would be one thing. But we have other diseases affecting other species now as well. The red band needle blight affects Lodgepole and Scots Pine, the latter being one of our most iconic species. We have another disease affecting larch trees, another of our most treasured species. What would happen if we had a disease affecting Sitka Spruce, which comprises fifty percent of our overall woodland area?
We need to be concerned about ash trees as they are immensely useful to us. In 1825, William Corbett wrote of the ash in The Woodlanders:
“ It gives us boards, materials for making instruments of husbandry, and contributes to the making of tools of all sorts. We could not well have a wagon, a cart, a coach or a wheelbarrow, a plough, a harrow, a spade, an axe or a hammer if we had no Ash. It gives us pales for our hops, hurdle gates wherewith to pen our sheep, and hoops for our washing tubs, and assists to supply the Irish and the West Indians with hoops for their pork barrels and hogsheads. It therefore demands our particular attention.”
In 2014, it remains a versatile species, being used for furniture and turning, and sports ash is especially valuable. It is a wonderful firewood, and should be a part of any small scale planting.
                                     Logs to Burn
                                     Ash logs, all smooth and gray,
                                     Burn them green or old.
                                     Buy up all that comes your way,
                                     They’re worth their weight in gold.
                                     Anon, date unknown.
                                                                                       (From James, NDG 1973 ‘A Book of Trees’)

I did my Honours thesis on ash trees in 1990. I would rather not hear chainsaws in every wood in Highland Perthshire in the near future. Whether that will happen or not, I don’t know.

Pictured top is Ash in planted woodland and, below, open grown Ash

Victor Clements
Woodland advisor based in Aberfeldy in Highland Perthshire



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