| Species | Effect/Damage | Image |
|---|
| Grey Squirrel (Sciurus carolinensis) - Has been in the top ten for many years and just keeps on going! | Economic - Damage to growing shoots of trees, ring barking and potentially killing trees. Can cause damage that makes some tree species, e.g. beech, not worth growing for timber. |  |
Deer - Various species and has been climbing the charts consistently. Numbers are growing and putting pressure on woods. Also involved in road traffic accidents. Link to the South West regional News page on the Deer Initiative's website For further information on the DI's work in the South West, contact Norman Healey at southwest@thedeerinitiative.co.uk | Economic & Biodiversity - Can eat saplings and shoots, killing regrowth and stopping natural regeneration of trees. |  |
'Sudden Oak Death' (Phytophthora ramorum) - A relatively new performer from 2003, made its entrance to the charts in Cornwall but has ambitions to spread. Hitches a ride on Rhododendron species. Link to the Defra Plant Health pages on P. ramorum | Economic & Biodiversity - Causes decline and eventually death on a range of tree species. Host species, e.g. Rhododendron may need removal. Can be an issue in ornamental gardens. |  |
Phytophthora kernoviae - Friend and relative of P. ramorum, discovered in Cornwall 2004 and now, like its kin, aims to increase its success by moving further afield. Has travelled as far as Scotland. Forest Research publication on P. kernoviae (PDF 258KB) Link to the Defra Plant Health pages on P. kernoviae | As for P. ramorum |  |
Red Band Needle Blight (Dothistroma septosporum) - Another micro-organism that affects mostly Corsican Pine, an economically important tree. It is now widespread in GB and in the South West. It made early, sporadic entries in the fifties and sixties, but only really got going in the late nineties/ early 21st century. May like wetter, milder climate. FAQs about RBNB (PDF 36KB) Forest Research publication on Red Band Needle Blight (PDF 1.2MB) | Economic - Excessive needle drop leading to weakened growth and eventual death. |  |
Horse Chestnut Leaf Miner (Cameraria ohridella) - A moth whose larvae munches leaves and causes defoliation. Entered the charts in Wimbledon in 2002 and is now found in the northern and eastern part of the South West region. Leaves look browned. Forest Research publication on the Horse Chestnut Leaf Miner (PDF 179KB) | Amenity - Premature leaf drop, and looks ugly, but doesn't permanently harm the tree. |  |
Asian Longhorn Beetle (Anoplophora glabripennis) - A new entry from China. A big beetle (up to 37mm long with very long antenna), whose larvae bores into trees and shrubs and feeds on their internal organs. FC publication on the Asian Longhorn beetle (PDF 545KB) | Weakens trees and shrub structure and leaves them open to diseases and wind damage. |  |
Horse Chestnut Bleeding Canker - Widespread in England and the South West and caused by bacterium. Obvious signs are oozing patches of gummy liquid on the bark. Forest publication on Horse Chestnut Bleeding Canker (PDF 852KB) | Bark dies, dries and cracks, allowing fungi in. This may eventually ring the whole tree and cause death. |  |
| Humans (Homo sapiens) - Yes, you and me! One of the most common forms of unintentional damage to trees is sloppy mowing and strimming. This can damage and remove bark - it looks ugly and can allow micro-organisms in. | Bark removal all the way round the tree may cause death. Other damage lets in diseases which can, in turn weaken or kill the tree. |  |