Pigs and wild boar
Source: gov.uk (2025-10-30)

Learn more about protecting trees from the domestic pig (Sus domesticus) and wild boar (Sus scrofa).

Area and status

Wild boar were once native to the UK but became extinct in the wild by the 17th century, largely due to habitat loss and overhunting.

In recent decades, feral wild boar populations have returned to southern England following escapes from farms and deliberate releases. The largest population is in the Forest of Dean, Gloucestershire, where numbers reached an estimated 1,635 animals in 2019. Smaller populations exist in Kent, Sussex, Herefordshire, Devon, and Dorset, as well as localised areas in Wales and Scotland.

Wild boar farming in the England is regulated under the Dangerous Wild Animals Act 1976 (https://www.legislation.gov.uk/ukpga/1976/38), while domestic pig welfare is protected by the Animal Welfare Act 2006 (https://www.legislation.gov.uk/ukpga/2006/45/contents).

Feral wild boar have no specific legal protection but are covered under general wildlife legislation including the Wild Mammals (Protection) Act 1996 (https://www.legislation.gov.uk/ukpga/1996/3/contents) and the Wildlife and Countryside Act 1981 (https://www.legislation.gov.uk/ukpga/1981/69).

It is likely there has been significant genetic mixing between wild boar and domestic pigs. Some domestic pig breeds are used for woodland grazing and management. This guidance covers both because they have similar impacts on woodland ecosystems and trees.

Associated treescapes
- lowland broadleaved woodland (https://woodlandwildlifetoolkit.sylva.org.uk/advice-types-broadleaf) (most common)
- wet woodland (https://woodlandwildlifetoolkit.sylva.org.uk/advice-types-broadleaf) (frequently found)
- mixed plantation (https://woodlandwildlifetoolkit.sylva.org.uk/advice-types-conifer) (frequently found)
- wood pasture, parkland and orchards (https://woodlandwildlifetoolkit.sylva.org.uk/advice-types-broadleaf) (frequently found)
Ecosystem services and impacts on biodiversity

Rooting behaviour can:
- reduce rank vegetation and bracken cover
- promote new plant growth by uncovering dormant seeds in the soil and provide a seed bed for natural regeneration
However, excessive rooting can mix soil layers. This reduces vegetation cover and leaf litter, increases nitrate concentrations and soil respiration, and decreases the abundance of soil arthropods. High densities can completely remove woodland ground flora, including valued species such as pignut and bluebell.

Identification and assessment of damage and risk to trees

Rooting damage
- most common sign of domestic pig and wild boar activity
- can damage trees at all stages of growth
- mature trees are vulnerable to fine root and mycorrhizae damage
- high densities can lead to soil structural damage
- concerning for ancient and veteran trees that need stable soil conditions and intact root networks for their longevity and resilience
Rubbing damage
- domestic pigs and wild boar may rub against mature trees, leading to bark damage
- can lead to nutrient deficiencies, disease susceptibility, stunted growth, and tree death
- more likely with domestic pigs where movement is restricted
Wild boar damage can be distinguished from that caused by other animals, like badgers, based on several factors:
- soil disturbance is typically 5 to 15cm deep (compared to badger disturbance which is less than 5cm)
- larger rooted patches
- large snout marks often visible at the edges of the patches
- wild boar hair has distinctive whitish split ends, which can sometimes get caught in fences
Domestic pigs and wild boar are large, powerful animals. They can damage fencing, allowing other species to enter enclosures and cause further damage.

Managing pigs and wild boar in the landscape

Widespread use

Lethal control: shooting and trapping (https://www.gov.uk/guidance/protecting-trees-from-mammal-damage-technical-guidance/managing-mammals-in-the-landscape#lethal-control).

Occasional use

Non-lethal control: stocking rate, stocking density, and timing and pattern of grazing (https://www.gov.uk/guidance/protecting-trees-from-mammal-damage-technical-guidance/managing-mammals-in-the-landscape#stocking).

In trial or development

Non-lethal control: immunocontraception (https://www.gov.uk/guidance/protecting-trees-from-mammal-damage-technical-guidance/managing-mammals-in-the-landscape#immunocontraception).

Any control must be conducted in line with animal welfare legislation such as the Wild Mammals (Protection) Act 1996 and the Animal Welfare Act 2006.

Modifying pigs and wild boar access to trees

Widespread use

Physical exclusion from an area: fencing (https://www.gov.uk/guidance/protecting-trees-from-mammal-damage-technical-guidance/modifying-mammal-access-to-trees#exclusion-from-an-area).

Any control must be conducted in line with animal welfare legislation such as the Wild Mammals (Protection) Act 1996 and the Animal Welfare Act 2006.

Additional information, guidance and resources

Case studies, trials, and scientific research

Forestry England

More information about wild boar in the Forest of Dean (https://www.forestryengland.uk/article/more-information-about-wild-boar).

Support, advice, and guidance

The Deer Initiative Partnership

A best practice guide on fencing standards, aimed at preventing both the escape of captive pigs and wild boar and restricting the introduction of feral wild boar into areas where they are not wanted (https://www.wild-boar.org.uk/).

Guidance on how to shoot wild boar humanely and safely, including recommendations on appropriate firearms (https://www.wild-boar.org.uk/).

British Association for Shooting and Conservation (BASC) (https://basc.org.uk/deer/wild-boar/)