Dangerous trees in Gifford Woods - Update on our Tree Safety Work

As we've mentioned previously, windy weather earlier this year has highlighted that some trees needed our attention to make them safe for all users of the woods.  Below is a bit more information on what we've been doing and why.

Dead standing birch trees

Birches are not often particularly long-lived trees and once dead, start to rot from the top down. Obvious indicators are bracket fungi such as the birch polypore and the hoof fungus. Although dead standing wood is an important habitat for many birds, insects and fungi, dead birch is particularly unstable and in a high wind or if someone bangs into a tree or shakes it, the top 1 – 1.5 m of the tree can drop suddenly. Where these trees are close to paths and neighbour’s property, we make it a priority to either reduce these or fell them entirely.

Sycamore trees and cankers

Many of the sycamore trees in the woodland are affected by a Nectria fungus closely related to Coral Spot which is the fungus that looks like little orange dots on the fallen twigs. However, unlike Coral Spot it forms deep cankers in the trunk and branches of the trees and makes all the timber above the canker, often several tonnes worth, highly unstable. The fungus can also cause a butt rot which undermines the base of the tree leaving little to support the entire trunk and canopy. Often these are particularly large trees and extremely dangerous. Where we have such trees close to the path network, we must put public safety first and fell them. If the trees are away from the paths and not a high threat to passers-by or a boundary fence, we will leave them for nature to take its course.

 

Dead or dangerous oaks

Some of the oak trees in the woodland are extremely old. In fact indicator fungi found in the woods suggest there has been a continuity of oak here since it returned after the retreating ice at the end of the ice age. Several of these fungi are heartwood rot fungi and do not pose any significant risk as the tree does not require the heartwood to function and a hollow cylinder can make a very strong structure. However, if a white rot fungus, such as Honey Fungus, gets into the base of these trees the become very dangerous. By the nature of such a long-lived species, they can become very large and extremely tall. Most of the larger oaks in the woodland are at least 60 cm in diameter, if not broader still and at least 12 m tall. When trees like this fall and they will at some point, they can cause a lot of damage and so it is important that we take them down in a controlled manner to limit the damage to other trees and danger to the public.

Hung Branches

These probably speak for themselves! There are many dead branches in the canopy of the woodland and mostly these are fine until a storm with high winds brings them down. If they fall to the ground, they are harmless – it is best not to wander around a woodland in a storm though! However if the branches don’t reach the ground and get snagged in other branches, particularly where they hang directly over a path, we need to climb the tree and cut them out.

 Chalara, Ash Dieback

This tree disease has affected many of the ash trees in the community wooldand and there is nothing we can do to stop it infecting more trees. Typical signs are leaf wilt and diamond shaped scarring in young shoots at the point the shoots start to branch.

Mature trees tend to leaf up irregularly and the real test for the woodland will be whether these trees leaf up at all next year.

Forestry Scotland advise that ash trees are extremely important for biodiversity. Fallen ash leaves decompose rapidly, forming rich soils with little litter accumulation compared to most other native tree species. It also casts a very light shade, and the ground flora tends to be lush and species rich. Where possible, diseased or dead ash trees should not be felled or removed from woodland, nor should ash trees be thinned from stands pre-emptively. These trees, whether living or dead, have value for biodiversity. Furthermore, some may prove to be more tolerant to Chalara than others, and may therefore provide material for future breeding programmes. If trees have to be felled for health and safety reasons consider leaving the felled trunks intact on site where possible, since the dead wood will continue to be valuable for biodiversity. Promoting natural regeneration of ash is recommended. This allows natural selection to favour any tolerant individuals present in the population. Since this trait is heritable, continued recruitment of a large quantity of regeneration may be required to build up the population of tolerant individuals.

Nesting Bird season

The season for birds to nest in Scotland is from 1^st Feb to 31^st August. We would always plan scheduled tree safety work to not coincide with the nesting season. However, if we recognise that is dangerous during that period, we have to make a decision whether the tree or hanging branch presents a threat to the public using the woodland.

Key points regarding the law relating to trees and hedges are as follows:

• Only a Tree Preservation Order, the Hedgerow Regulations 1997, or a nature conservation site designation can secure the long‐term protection of trees, hedgerows or woodlands. Other temporary protection can be secured by means of planning conditions on development, and designation of an area as a ‘Conservation Area’.
• The presence of nesting birds (protected under the Wildlife & Countryside Act 1981) can delay, but not prevent, the felling of trees, hedgerows and woodlands.
• Work to hedgerows, trees and woodlands can take place at any time of year, but the onus is on the person doing the work to avoid committing an offence under the Wildlife & Countryside Act 1981. Hedges, trees and groups of trees are always someone’s property. Subject to certain constraints, outlined below, the owner is allowed to do whatever they want with their property.
• Public safety issues can override other management and planning considerations, and even the Wildlife & Countryside Act 1981. Dead, dying or dangerous branches or trees are specifically exempt from Tree Preservation Order control.
• If a branch or even a whole tree has become a safety hazard, it can be removed at any time to make it safe. However, if there is a reasonable way of removing the safety risk while allowing the birds to finish nesting (e.g. by a temporary path closure which does not cause any practical problems), the Wildlife & Countryside Act 1981 requires that such alternatives be considered.

The woodland was assessed for dangerous trees at the beginning of February this year. A list of trees that required attention was drawn up and contractors were asked to submit quotations to complete the necessary work. It was our intention to complete this work before the end of that month or at least as early as possible. We accepted a quotation from a contractor but could not proceed with the safety work due to lack of funding. Since then, volunteers with the necessary experience have stepped forward to help us begin this work. Only trees that pose a significant threat to the public are being worked on and all identified trees and those in the felling line are carefully checked for bird’s nests as well as the target felling area on the ground. With the increased footfall within the woodland, as many people use it as the destination of their permitted recreation, it has made this safety work all the more urgent and it would not be appropriate to close all the affected paths within the woodland until the end of the nesting season.