PGP Beaver Talk on 19th March 2026
Rob Cullen – Forest of Dean Waters Manager
Stewart Cooper – Forest of Dean Waters Supervisor
Rob and Stewart gave a fascinating and highly informative talk on how the hydrology of The Forest is being managed which included a full explanation of the work of their Beaver Project.
Part I The Forest Management Plan
A Forest Management Plan was drawn up in 2019 recognising that the water landscape has been highly modified in the past through mining and other exploitative practices since Roman times through the middle ages to its peak in the coal mining of the 18th and 19th centuries, fuelling the Industrial revolution. In the 20th century open cast mining continued but forest plantation work involving extensive cutting of drainage ditches added to the extensive modification of the Forest’s drainage.
The 2019 Management plan aims to promote ecological and environmental enhancement through restoring natural processes.
Present Issues in the Forest of Dean. These can be divided into above and below ground issues. Above being the linear drainage channels frequently modified and the large network of undergound tunnels and mine shafts.
- Drainage
- Industry
- Loss to mine workings
- Water as a source of power
- Watercourse modification
- Loss of riparian habitats
- Lots of trees – always a good thing?
- Loss of connectivity of habitats
The map on the left of the image above is of Parkhill inclosure map 1883 and to the right a lidar image of the same area present day. Sources: https://maps.nls.uk/ and Environment Agency showing the straightening of the Cannop Brook to speed flow to The Severn. Each time a channel has been modified, habitats have been lost.
Since World War I the extensive spruce planting to offset timber loss through the war has had a negative impact upon wildlife and fish which the 2017 Forest Management Plan aims to address.
Of the four main Forest of Dean catchments Forest England is the most extensive land manager, guided by management plans. They work in partnership with Gloucestershire County Council, awarded a grant of £850,000 for Natural Flood Management on Cannop Brook. The Severn Rivers Trust is an independent charity supporting the restoration of the Cinderford (Soudley) Brook
River Restoration – restoring artificially made channels to their natural course.
Wetland Restoration
It is now recognised that The Forest area that has been lost to drainage in times of past and more recent forestry is being restored – the benefits being to buffer and slow the drainage of water lowering flooding risk downstream, increasing carbon sequestration and enhancing local habitats. Around Speech House walk there has been a 20 hectare Foxes bridge valley mire restoration project involving tree clearance and replanting.
Riparian buffering. This is the establishment of specific species and structure, typically widely-spaced of alder, willow, aspen and miscellaneous broadleaf trees. The aims are to reduce erosion and sediment loading, provide natural flood management through beaver colonisation and the creation of habitat and wildlife corridors. Included in these new Forest England management practices is the use of large woody debris such as smaller felled trees to interrupt and alter stream flow thus slowing the river flow outside of the two beaver compounds.
Assessment of artificial structures. This includes culverts, leats, weirs and dams constructed in the past which can be barriers to fish migration and sediment movement. The options are to bypass or remove these obstacles which may have heritage and recreation value (eg Cannop Ponds). Forest England looks for cost and benefit to find realistic solutions. Sometimes these have to be managed sensitively.
An example here is the bypassing of the sluice at Cannop Colliery. The project is designed to naturalise the water channel, improve habitats for fish species like eel and lamprey and manage flood risks.
Part II Volunteering in The Forest
Stewart described how volunteers give their time freely and without obligation. The diverse nature of their work brings a range of experience and perspectives that enhance forests and services both for staff and visitors. As well as contributing without payment their activities support health and wellbeing, help outreach to our local communities and create great ambassadors for Forestry England. In 2018-19 volunteers supporting the nation’s forest contributed over 209,000 hours equating to a value of £2,337,000.
Tasks such as litter picking, tree guard removal and planting, trail surface maintenance and conservation works can be the types of tasks volunteers choose. We were encouraged to sign up!
At Perry Hay two adults beavers have been introduced into an exciting new 12-hectare enclosure. To help protect them, volunteers are needed to walk the length of the fence to check its integrity on a rota basis.
Part III Beavers
Beavers are masters at being ecosystem engineers. Since The last glacial retreat 10-12,000 years ago there were many breeding in Britain but by the end of the 19th century there were very few throughout Europe and none in the British Isles
Beavers were hunted extensively for their fur, meat and castoreum, described historically as having ‘a highly disagreeable odour’ and ‘seriously musky sensuality’ as a perfume and natural remedy. Beavers were widespread in early middle ages, evidence being from place names such as Beaverbrook.
Hywel Dda in the 10th century wrote in his Welsh Laws that beaver skins were royal privileges, in the 12th century they were documented on the river Tefi (In The Journal of Gerald of Wales ‘The Journey Through Wales’. ) and at Nant Francon in late 17th century.
Beavers were largely extinct in England and Wales and by the 12th century and Scotland by the 16th century.
Why bring back beavers? they are of intrinsic value because of their significant impact on ecological processes. They are true ‘Ecosystem Engineers’ through felling trees, creating glades and creating pools and marginal wetlands. All this slows the flow of moving water benefiting flood prevention further downstream.
The flood risk benefit has been shown in Devon through measurement of river height over time during a storm above the beaver area and below
This hydrograph shows that the stream above the beavers is more peaky during prolonged rainfall whilst below in the beaver area the stream level rises more gradually. Furthermore beavers have a positive impact on sediment accumulation, phosphate, nitrate and dissolved organic carbon levels shown by this graph.
Beavers build dams at the top of the catchment which creates pools for fish to spawn and are highly beneficial for invertebrates, amphibians, reptiles, birds mammals and fish.
The introduction of beavers to a catchment isn’t always received favourably by the public. Public perceptions versus reality can clash, fuelled by social media coverage and general resistance to change. This can delay their introduction yet there is an opportunity cost of inaction. Whilst dams can be seen as a barrier to fish movement beaver dams are mostly built above fish spawning grounds and are not as interfering of fish movement as concrete dams. It has been questioned if the resulting silt retention of beaver dam construction can bury valuable habitats but they do create a habitat for juvenile and adult salmonids. In times of climate change these pools become drought refugia and the decaying woody material they create increases invertebrates for feeding. So there are complex costs and benefits at a landscape scale, a co-evolutionary history.
Impact on forestry. Beavers fell trees! the majority of felling occurs within 10 meters of the water’s edge. As they favour broadleaf trees the trees grow back as they are in effect coppiced by the beavers. In the few cases where they have caused problems in agricultural areas farmers have been compensated as their benefits still outweigh any disadvantages (Grazing of crops, vegetables, fruit trees , dams creating local flooded areas on farmland)
In today’s forestry work they compliment the modern day multipurpose forest – timber production, recreation and wildlife. Where they have interfered with infrastructure such as blocking culverts, wetting access routes, felling trees and flood defences there are mitigation strategies such as beaver dam removal or modification embankment reinforcement, culvert protection, tree protection, electric fencing, trapping and relocation and even culling.
The first beaver enclosure was at Greathough Brook by Lydbrook in 2018. On the map below the beaver enclosure area is outlined in green.
Their impact since then can be shown by this recent aerial photograph
The second and more recent enclosure is at Perry Hay (near Speech House) which is drained by Blackpool Brook into the River Severn.
Forest England was granted a licence by Natural England in early 2024 and a pair of Beavers released in May 2024, a Scottish Female and a Yorkshire Male.
The present situation and future considerations
We now have a wild population in Britain through lawful releases, escapees, unlawful releases and population growth
The large cluster of beavers in Scotland reflect an earlier decision by Natural Scotland to allow wild releases. In Feb 2025 Natural England announced that they will consider applications for release of Beavers into the Wild and so in March 2025 and shortly after the National Trust released four beavers into the wild at Purbeck heath in Dorset.
A public opinion survey carried out in Gloucestershire showed large support for the introduction of beavers into the wild.
You can visit the beaver enclosures at Greathough (Google maps)and Perryhay in The Forest and use the footpaths to walk the perimeter fences. You would be very lucky to spot the beavers in the daytime but you will almost certainly see the evidence of their work
