Horse Chestnut trees all over the Southeast suffer from a number of disorders; a form of bacterial canker, an exotic leaf miner and leaf scorch caused by water stress.
Bacterial canker kills areas of bark, interrupting the flow of sap causing yellowing of the leaves in the upper canopy. The tree 'bleeds' in an effort to heal itself. The disease
is not thought to be terminal.
The Chestnut Leaf Miner is a small moth whose larvae eat the tissue between the leaf surfaces. Though the trees seem to be under stress there is, so far, no evidence that any tree has died or suffered any form of long term damage or decline following infestation. It is thought that by the time severe damage from Leaf Miner occurs late in the season (August/September) it has occurred too late to affect the performance of the tree. Management options for controlling the pest are being currently investigated by the Institute of Forest Research
Sadly, some are damaged by motor vehicles or vandalism. If you are aware of such problems just pick up the phone and report it. The number to ring at Sutton Council is 8770 5070 or 8770 5000 in an emergency.
Maintenance tasks for young trees can include:
Trees planted in the highway all have watering tubes at the base. If there is a tree near your house – please give it a drink every now and then, it will help the tree survive in times of drought. Young trees benefit most from long drinks on an irregular basis.
Grasses and other fast growing herbaceous plants growing at the bases of young trees compete for moisture, nutrients, space and light. To help the tree get established it is important that we keep an area about 1m² free from weeds.
Help the tree by pulling out grasses and herbaceous plants. Hoeing runs the risk of damaging the roots of the young tree and cutting the weeds just encourages them to grow.
Chemical control of weeds around the base of trees is likely to do the young trees harm.
Fertilising young trees may not actually help them as the young tree uses energy to absorb the nutrients from the fertiliser. Also the lush growth promoted by fertiliser is vulnerable to pests and diseases.
When young trees are planted the backfilled topsoil contains organic matter. This should be enough to help the young trees get established and they shouldn’t need extra fertiliser.
Dead or dying trees
Dieback usually occurs on the outermost branches first. Look for failure to flush in spring or early leaf fall.
If blocking the road or a footpath please contact your Co-ordinator as soon as possible.
Bark stripped from the trunk – though not an emergency as the damage has already been done, please let us know as soon as possible so that we can prevent damage to nearby trees. Dogs have damaged a number of young trees in Sutton’s parks by pulling off lower branches of trees and stripping the lower bark. If you see this type of damage on young trees, inform your Tree Warden Co-ordinator. The solution is to apply biodegradable grease to the trunk to deter the dogs.
When a vehicle hits a tree damage can be severe enough in some cases to cause the wood fibres to buckle and the tree to fail. If you see that a tree in your area has been hit, please inform your Tree Warden Co-ordinator as soon as possible.
How to report hazards
If you identify any of the above, please contact Council. Tel: 020 8770 5070 or direct on 020 8770 6399 / 07736 338378.
Salt damage and pollution
Trees damaged by salt will show signs of water stress (necrosis around the leaf margins/small leaves/stunted growth). This type of damage is common where road salt bins are leaking. If you see this type of damage to trees near salt bins, inform your Tree Warden Co-ordinator so that we can fix the leak.
Biotic hazards (Pests & Diseases)
Thanks to increased global trade the number of invasive pests and diseases entering the UK has increased. This is significant as introduced pests or diseases can spread or establish populations and damage Britain’s trees. There are several pests and diseases Tree Wardens should be on the look out for in their area. Most significantly:
§ Oak Processionary Moth
§ Gypsy Moth
§ Asian Longhorn and Citrus Beetle
§ Emerald Ash Borer
§ Spruce Bark Beetle
Should you find any of these on trees in our area, contact the council immediately on 8770 5070 or 8770 5000, or contact Forest Research on 01420 22255.
They don’t always indicate decay and instability, but should you see something similar, please let your Co-ordinator know.
Inonotus hispidus on a Whitebeam.
Oak Processionary Moth
Please let the LBS or Forest Research know as soon as possible – the caterpillars can cause harm to humans as well as trees. What appears to be fur, is in fact bristles which the caterpillars shed and which are toxic, so, do not handle them, and if you have an infestation stay away as the bristles can cause respiratory problems.
Contact the borough council on 0208 770 5070 or on TreesEmergency@sutton.gov.uk