Summary
An assessment of the afforested
Peat Resource in Wales
Summary of the findings of the report “A strategic assessment of the afforested peat
resource in Wales, and the biodiversity, greenhouse gas flux and hydrological
implications of various management approaches for targeting peatland restoration”.
This report helps identify the opportunities for restoration of afforested deep peat and
prioritise restoration efforts.
Purpose
Produce improved distribution maps of
the peatland in Wales.
Develop
rule-based
criteria
to
strategically assess the afforested deep
peat resource in Wales, and its
potential for delivery of ecosystem
services.
Establish priority sites for restoration
based on these criteria.
Develop a field assessment tool to
evaluate a site’s potential for viable
restoration to active bog habitat.
Overview
18,092 hectares (ha) of woodland are estimated to be on deep peat soils in Wales.
Of which 11,038 ha is owned by Welsh Government, with a little under 7,000 ha of
that being under coniferous plantations.
Restoration potential was assessed nationally and priority sites were mapped
according to their potential delivery of ecosystem service benefit (carbon storage and
sequestration, hydrology and biodiversity).
Background
Peatland in pristine or good condition provides a range of critical ecosystem services,
including biodiversity, carbon storage and sequestration, regulation of stream base
flows, water runoff and downstream flood peaks and nutrient regulation and
retention. Peatlands are also sinks and sources of several natural greenhouse gases,
particularly carbon dioxide (CO2) and methane (CH4).
Peatlands that are in poor condition may be drying and oxidising, which will cause
them to emit carbon, whereas peatland in good condition will be peat forming, and
therefore sequestering carbon.
More than 75% of deep peat soils in Wales are covered in semi-natural vegetation.
Most of this is upland blanket bog, with significant amounts of fen and flush and,
locally, lowland raised bog. These are all UK Biodiversity Action Plan priority habitats
with UK and Welsh targets for habitat management and restoration.
The focus of this work is the 18,092ha of deep peat which is under woodland cover.
Assessment of peat resource
Summary
Definition
Peat which is more than 50cm in depth is defined as deep peat under UKFS. A
precautionary approach has been taken in this work, which means that the new map
probably over-estimates the extent of deep peat.
Distribution
The most extensive areas of
peatland habitat are the upland
blanket bogs (23,400 ha) mostly in
North Wales and the substantial
area of wet modified bog (22,600
ha) mostly in the uplands of central
Wales.
Much of the forestry in Wales is
also located in these areas because
when they were initially planted to
meet the country’s timber needs, it
was the marginal agricultural land
that was made available for the
afforestation.
Much of the deep peat in Wales is
part of a mosaic of soil types rather
than being in large blocks. Within
the more expansive areas of peat
there are often pockets of other soil
types as well.
National Assessment
The focus of Forestry Commission Wales is to enable the greatest delivery of
ecosystem services. This includes timber production and recreation, however, where
trees were planted on deep peat (a practice which no longer occurs), it may be that
restoring the peat to active bog habitat offers greater benefit across the range of
ecosystem services.
Sites which will be prioritised for restoration are those which have the greatest
potential to provide benefits for biodiversity, improve the integrity of hydrological
source areas and their capacity to regulate water flow and storage, and provide
optimal greenhouse gas storage and sequestration.
The national assessment scheme applies spatial datasets to assess five issues: a)
current status of the peat; b) hydrological integrity of the site; c) consequence of
restoration in terms of greenhouse gas emissions; d) ecological integrity of the site
and e) climatic integrity of the site. The rule-based criteria score a site's potential for
restoration so that the sites with good potential to become peat forming habitats have
higher scores than those which will merely retain the existing peat.
At a national level, each issue has been assessed and mapped separately (peat
condition, hydrology, greenhouse gas balance, biodiversity, and climate integrity).
The five issues are then combined using weighting factors to determine the final score
for each site and produce the national map.
Assessment of peat resource
Summary
Prioritisation and the
Top 10 Sites
The
results
of
the
national
assessment reveal where the best
opportunities for restoration are
(excluding consideration of other
factors beyond the scope of this
study) – these are shown in green
on the map.
The sites which ranked in the top
10 (outlined in blue) are identified
as priority sites.
These priority sites have been
assessed on the ground by an
expert in the field to establish if the
sites
are
really
viable
for
restoration by applying the field
assessment tool.
These sites will be the focus for
restoration efforts by Forestry
Commission Wales.
Options for sites not viable for restoration
It is essential for the successful restoration of peatland that the water table can be
raised and maintained. Where this is not possible, for example due to slope and
cracking of the peat structure, an alternative to bog restoration must be sought.
Options include creation of open heathland habitat, native or wet woodland, or
continue to carry out commercial forestry on the site to lock up carbon and supply
timber. These options need to be considered at each site that is not viable for bog
restoration, according to the ecosystem service benefit and likelihood of success.
Restoration Methods
and Costs
The primary aim in bog restoration is
to keep the water table level high to
allow sphagnum moss to accumulate.
This is generally achieved by removing
trees and blocking any ditches on site.
The cost of this work varies greatly,
but broadly speaking is in the region of
£ 1,600 / ha.
Assessment of peat resource
Summary
Management
A site cannot be considered viable for restoration if success cannot be achieved in a
reasonable timescale and that, once restored, the site cannot be self maintaining
without a need for continual intensive intervention.
Some ongoing management of these sites is expected. It is important to monitor the
success of the works which have been undertaken and ensure the area is not
deteriorating.
The most likely ongoing problem is that of regeneration of conifer species. These can
be manually removed or a low intensity grazing system may be implemented.
Field Assessment
A field assessment tool has been
developed to enable forestry staff
(such as planners and conservation
managers) to evaluate all the areas of
afforested deep peat highlighted in the
national assessment and prioritise
those sites where restoration is most
viable.
This tool is simple and easy to apply,
information on soil type, peat depth,
area and slope form the basis of this
tool.
It enables local decision making on the
priority sites. It also guides managers
away from committing resources to
areas which are not viable or not
going to deliver greatest ecosystem
service benefit.
Field Assessment Tool
Next Steps
There is an accompanying piece of
guidance on forestry and restoration
of peatland, which gives an indication
of policy direction and outlines the
need for a programme to be
developed to assess afforested deep
peat and future management.
The Top 10 sites will be put into a
programme of action to be undertaken
on the Welsh Government Woodland
Estate
(WGWE)
by
2027.
The
remaining afforested deep peat within
the WGWE will be assessed using the
Field Assessment Tool by 2017.
Areas of afforested deep peat in
private ownership will be subject to
changes in felling licence conditions
and we are in discussion with Welsh
Government to ensure funds will be
made available through Glastir for bog
restoration where appropriate.
The report, “A strategic assessment of the afforested peat resource in
Wales and the biodiversity, greenhouse gas flux and hydrological
implications of various management approaches for targeting peatland
restoration” was conducted by Elena Vanguelova, Samantha Broadmeadow,
Russell Anderson, Sirwan Yamulki, Tim Randle, Tom Nisbet and James Morison of
Forest Research.
This work was commissioned by Forestry Commission Wales, with support from the
Countryside Council for Wales, with Welsh Government and Environment Agency
Wales also represented on the steering group.