I HAVE never been very fond of ash trees (Fraxinus excelsior) chiefly because in every garden I have had they have seeded themselves like weeds. And they are crafty – they conceal themselves within other shrubs and plants so that you don’t notice them until they are very nearly full-grown trees. It is no use just cutting them down – unlike some other unwanted saplings they don’t take the hint but throw up half a dozen stout new stems.
However ash trees are having a tough time and it is possible that soon there won’t any left to plague gardeners. They are becoming infected with a disease called ash dieback and the Woodland Trust estimates that 80 per cent of the ash trees in Britain will succumb to it.
The cause is a fungus (Hymenoscyphus fraxineus) which originated in Asia. It doesn’t cause much damage to its native hosts, the Manchurian ash (Fraxinus mandshurica) and the Chinese ash (Fraxinus chinensis), but our species has no natural defence against it. It spread to Europe about 30 years ago, and at that time, inexplicably, we were importing thousands of ash saplings from Europe. The spores are carried on the wind and it spread rapidly from the young trees to mature specimens.
(As an aside, how was this allowed to happen? The disease must have been known about.)
The fungus penetrates the leaves and stems of the tree, blocking its water transport systems, and causing the leaves and stems furthest from the trunk to blacken and die, as you can see here. Mature trees respond by sending out bunches of new stems from dormant buds in a process called epicormic growth. This is easiest to see in the winter, and I took this picture of an afflicted tree last week.
In the following pictures you can see the new shoots.
A mature tree can cope with the disease for a while but with repeated re-infection it will eventually weaken and become prey to other diseases and die. It is thought that some trees may have natural immunity and that they will reproduce and eventually re-stock the landscape, but we are talking a minimum of 50 years.
A group called Observatree is monitoring the spread of this and other tree diseases and you can report sightings here.
We used to sing a traditional Welsh song called The Ash Grove at school. I wonder if generations to come, if they still sing such old-fashioned stuff, will ask what an ash grove is. Here’s a lovely performance by Cai Thomas.
While on a Welsh theme, I recently spotted this sign in some nearby woods.
According to the internet the nearest point in Wales is 77 miles from here.
Yet more mysterious activity by Lancashire County Council’s Highways Department. Last week a young man and a young woman were out and about with a van and a can of spray paint (yes, it took two of them), and this is part of their day’s work. This bit of road is a kind of cut-through used about half a dozen times a day, and the big holes have been ignored. Baffling.
A bit better than his egret snap which I featured last week, Alan got this terrific picture of Pendle Hill last week.
Don’t forget that our reader ‘linuslimmy’ is collating anecdotal evidence about bird and insect numbers, either increases or decreases (or even static). Send your comments and observations to this address: firstname.lastname@example.org. If you leave a comment below the line, we need a geographical location to be able to use it.