Summary
Every stage of tree growth may be attacked by one or more species of mammal. Often a species may cause damage at several growth stages. Most mammal damage to trees is from either:
- Browsing – feeding on buds, shoots and foliage
- Bark stripping from main stems or branches – gnawing or rubbing.
When trying to identify the cause of damage, the most important things to look for are:
- Form of damage (i.e. browsing, gnawing or rubbing)
- Height of damage
- Time of year when damage occurred
- Presence and size of teeth marks
- Signs of animal presence and abundance – droppings, footprints, runs, scrapes or burrows.
Points to note:
- Lack of teeth in front upper jaw of all deer species produces ragged edge on damaged twigs
- The teeth of rabbits and hares produce a sharp knife like cut. Muntjac may bite partly through thin tall stems and pull them down to eat
- Sheep and deer browsing damage is often very similar in form, but sheep tend to leave wool evidence
- Fraying is a rubbing injury caused when male deer rub new antlers to remove ‘velvet’ or to mark territories.
Findings and Recommendations
The following three tables show the main characteristics of damage by:
- wild deer
- other wild mammals including rabbits, hares, squirrels, mice, voles, edible dormice, moles and badgers
- domestic livestock
Brackets in the ‘age of trees’ column denote damage is uncommon.
Table A: Wild deer
| Species |
Age of trees affected |
Typical signs of damage to trees |
Comments; damage to other parts of woodland etc. |
| Red deer |
- Establishment
- Thicket
- Pole stage
- Mature
|
- Browse seedlings to thicket stage
- Fraying and rubbing on bark up to 1.8 m
|
- Damage to poor fences
- Severe damage to herb layer
|
| Sika deer |
- Establishment
- Thicket
- Pole stage
- Mature
|
- Browse seedlings to thicket stage
- Scoring of pole stage trunks
- Fraying and rubbing on bark up to 1.8 m
|
|
| Fallow deer |
- Establishment
- Thicket
- Pole stage
- (Mature)
|
- Browse seedlings to thicket stage
- Fraying bark up to 1.5 m
- May pull up recently planted trees
|
- Severe damage to herb layer
|
| Roe deer |
- Establishment
- Thicket
- Pole stage
- Mature
|
- Browse seedlings to thicket stage
- Fraying bark up to 1.2 m
|
- Severe damage to herb layer
|
| Muntjac deer |
|
- Browse seedlings to thicket stage
- Fraying bark up to 1 m
- May partly bite through taller stems and pull down to browse
|
- Capable of severe damage to herb layer
|
Table B: Other wild mammals
| Species |
Age of trees affected |
Typical signs of damage to trees |
Comments; damage to other parts of woodland etc. |
| Voles (bank & field) |
|
- Eating seeds, seedlings, root cutting of young planted stock
- Ringbarking up to 10 cm
- Teethmarks only 2 mm wide
- Bank vole will climb saplings and eat bark around base of branch
|
- Typical runways in grass with dropping and cut grass piles evident
- Nests in tree shelters
|
| Mice (wood, yellow-necked & house) |
|
|
- Seed stores
- Nests in tree shelters or under mulch mats
|
| Grey squirrel |
- Seedling
- Thicket
- Pole stage
- Mature
|
- Stripping bark anywhere on stem or branches of pole stage and mature trees
- Bark stripping at bottom 50 cm of stem may be confused with rabbit damage
|
- Eating larger seeds
- Predation of bird nests
|
| Edible dormouse |
|
- Spiral bark stripping at branch bases
|
- Very restricted range
- Hibernates below ground
- Compete for tree holes
|
| Rabbit |
- Establishment
- Seedling
- Thicket
- Pole stage
- (Mature)
|
- Cutting stems of planted saplings
- Ringbarking bottom 50 cm of stem
- Burrows assist windblow
- Sharp angled knife-like cuts on end of small stems or branches
- Removed portion often eaten
|
- Most vegetation in area around burrow often grazed very low
|
| Hare (mountain & brown) |
|
- Often sporadic but widespread
- May eat along a row of young trees
- Damage up to 70 cm
|
|
| Badger |
|
- Setts under roots
- Limited bark damage
|
- Create holes under fences for other pests to gain entry
|
| Mole |
|
- Tunnelling may cause desiccation of seedlings and transplant roots
- Soil heaps may bury young plants
|
- Assists drainage of gley soils
|
Table C: Domestic livestock
| Species |
Age of trees affected |
Tree and other collateral damage |
| Sheep |
- Establishment
- Thicket
- (Pole stage)
|
- Removal of ground vegetation
- Browsing and bark stripping
- Newly planted trees may be pulled out
|
| Goat |
- Establishment
- Thicket
- Pole stage
|
- Removal of ground vegetation
- Browsing and bark stripping
- Newly planted trees may be pulled out
|
| Cattle |
- Establishment
- Thicket
- Pole stage
|
- Removal of ground vegetation and newly planted trees or natural regeneration
- Treading impacts may be detrimental to roots or beneficial by providing nutrient and germination patches
- Coarse browsing of foliage to 1.5 m
- Newly planted trees may be pulled out
|
| Pigs & feral boar |
- Seedling
- Establishment
- Thicket
- Pole stage
- (Mature)
|
- Removal of large seeds, ground vegetation and natural regeneration
- Browsing and root damage by grubbing
- Digging rabbit burrows, holes created under fences
- Rubbing on trunks
|
| Ponies |
- Establishment
- Thicket
- (Pole stage)
|
- Newly planted trees may be pulled out
- Browsing to 2 metres
- Bark stripping with characteristic diagonal teeth marks from both jaws
- Grazing shrubs and ground flora
|
