Hymenoscyphus fraxineus / Chalara fraxinea / ASH DIEBACK

Dutch Elm Disease for the 21st century. Like it or not, it’s going nowhere. Well, actually, it’s going everywhere, including the South Hams.

Left: Healthy Ash, Centre: Javier dismantling an infected Ash.

There is no cure or treatment for the disease and over time infected trees will weaken, causing branches to fall and trees to eventually collapse and die. Infection can lead to the death of young trees in just two to three years and of mature trees within 3 to 5 years. This presents a significant health and safety risk, especially alongside roads, public rights of way and woodland areas used by the public for recreation activities. (source: gov.uk)

Dieback showing in twigs at the top of the crown.

Symptoms of ash dieback include;

  • On leaves: Black blotches appear, often at the leaf base and midrib. Affected leaves wilt
  • On stems: Small lens-shaped lesions or necrotic spots appear on the bark of stems and branches and enlarge to form perennial cankers. The infection may girdle the stem and kill it in a single season. If the bark is peeled, the wood underneath has a brownish to grey discolouration. This discolouration extends beyond the bark necrosis
  • On the whole tree: Affected trees show extensive dieback of shoots, twigs and branches. Trees often have prolific epicormic shoots (shoots produced from previously dormant buds below the bark of the trunk or branches) (source: rhs.org.uk)
Signs of dieback on stems.

Beech Maintenance.

Beech maintenance is best carried out during late Autumn, Winter, or once the tree has dropped it’s leaves. At this time, the majority of the tree’s nutrients have moved down into it’s roots, so when material is removed, less nutrients are lost.

If your Beech is in a small garden, close to overhead cables or next to a road or footpath, it’s a good idea to keep it’s size in check. This is done by carefully, and sympathetically reducing & thinning the crown at regular intervals.

Only a small amount should be removed at any one time, and this should be done no more frequently than 3 year intervals, to minimise stress to the tree. Before any thinning or reducing can be done, the whole tree should be checked for rubbing branches, and corrections made accordingly. The amount of rubbing branches removed, will dictate how much more can be removed during the thinning and/or reducing of the remaining crown.

Rubbing branches are a very common issue with Beeches. If left unattended, one of the branches will usually ‘win’, and one will ‘lose’, leading to a branch or limb failing, and ultimately falling. In a woodland this rarely causes an issue, and is part of the natural life cycle of the Beech. If however, there is a greenhouse or a footpath below, damage or injury could occur.

Once your Beech has dropped its leaves, take the opportunity to have a good look at the crown’s structure.

You know it’s going to be tricky if a farmer calls…

There isn’t much a farmer can’t fix with baler twine, and there aren’t many trees that can’t be dealt with using a rope and a tractor. So when we were called to a farm near Kingsbridge, to deal with a mature Ash with Dieback, we knew it was going to be a challenge.

Having already had some large roots severed, and with the infestation of Dieback, climbing and dismantling was out of the question. The only specifications were to avoid damage to the barn to the south, and the static caravan to the east, so the tree was headed north! Of course, no tree job on a farm would be complete without a rope and tractor, so for ‘belt & braces’ they were used to give a little tug on the right direction.

As usual, everything went according to plan.