Dulais Valley Forest Resource Plan

Location and setting

The new forest resource plan for the Dulais Valley covers 1,978Ha and incorporates 5 previous forest design plan units: Crynant Main, Crynant East, Nant y Cafn, Nant Stalwyn and Seven Sisters.

The majority of the forest estate area extends along both sides of the Dulais Valley close to the communities of Crynant and Seven Sisters. The largest of the forest blocks Crynant Main also extends over Mynydd Marchywel and into the Tawe Valley and are visible from the communities of Pontardawe and Ystalyfera.

The general geography of the area consists of gently sloping valley sides with good to moderate soils such as upland brown earths and flatter upland plateaus with poorer soils including peaty gleys with some small bog areas.

The altitude and exposure of the forest area also varies from 100m above sea level in the valley floor to 480m above sea level along Sarn Helen and the Hirfynydd ridge. This is also reflected in the exposure; DAMS scores vary between 10 on the valley bottom and 20 on the hilltops.

Most of the forest area was first planted in the 1950s, post second world war. Many of the first rotation crops have since been felled and restocked in the last 20 years but more recently large areas of larch have been felled and are in the process of being restocked.

A large proportion of the restocked sites have been successful in establishing young crops, but in a few areas crops have failed and resulted in semi open scrub rather than a young established forest.

A section of forest in the Seven Sisters forest block used for mineral extraction in the past is now part of a new mineral restoration project. Much of this area may be suitable for reforestation especially in areas with suitable soils.

The previous forest design plan for Crynant main and Nant Stalwyn was completed in 2012. However it was drafted during the initial Phytophthora outbreak when most of the larch was being felled and many of the remaining crops were identified as Low Impact Silvicultural Systems (LISS).  A recent silvicultural survey has suggested that a much lower proportion of crops are suitable for LISS especially in the wetter and more exposed parts of the forests.

Seven Sisters, Nant y Cafn and Crynant East were last drafted in 2002 and are well overdue for renewal. In these sections of the new plan area, much of the land designated as LISS has either been felled because of Phytophthora or has not been thinned and is now well past the first thinning age.

A more realistic management plan is necessary for the whole area, with a more rational approach to LISS and Continuous Cover Forest management. Future forest structure and species need to be updated as around 250Ha of the forest area has either been sold, allocated to grazing or form part of a mineral restoration projects.


Objectives and priorities


Many of the objectives and priorities discussed have multiple benefits including economic, operational, social and environmental. The brief will be presented with the following categories:


Felling Programming

The majority (240 Ha) of Phytophthora infected larch crops were felled between 2010 and 2012 resulting in large unstocked areas on some of the lower slopes of the forest. Some of the younger larch crops in Crynant East and all larch in Nant y Cafn are yet to be felled.

Together with some smaller unfinished areas in Crynant Main and Seven Sisters this still amounts to 60Ha in total across the new plan area. Although this is not a significantly large area, together with the existing felled areas and potential tidying up of other windblown crops around the larch felling this equates to approximately 15% of the forest area. Most of these areas are on the lower slopes and therefore accessed and visible by the majority of the population of the Dulais Valley.


Future Forest management and silviculture

The long term impact of the large scale felling of infected larch crops on forest management will result in the following:

  • future reduction of felling coupe sizes, numbers and timber volumes
  • further “mopping up” of the remaining larch crops and windblown crops to windfirm boundaries
  • retention of crops which may have been considered for felling sooner if P. ramorum had not infected adjacent larch crops
  • an increase of thinning of more marginal crops to help maintain forest cover in the long term

The removal of larch will have effects on the long term management plan of the forest. One major way to compensate for the large amount of felling in the coming years is to manage remaining crops by LISS/CCF where soils, slope and exposure allow. This type of management will be dependent on good silvicultural practice and the thinning of existing crops to be carried out on time. This is also important in Ancient Woodland Site management. 


Future Forest species and habitats

Large scale felling of larch crops will lead to an opportunity for greater diversity in both conifer crops and productive broadleaf crops in the long term.

Diversification of species is a key driver in future species and restock programs as per FCW ‘A Guide for increasing tree species diversity in Wales’ 2010. Large scale monocultures are to be avoided. Suitable species, provenances mixtures and nurse crops will be encouraged.

Larch and ash will not be replanted due to Phytophthora ramorum and Chalara fraxinea.

Bog restoration, creation of grazed acid grassland and other open space will also be identified at the FDP scale especially for, Scheduled Ancient Monuments, powerline wayleaves, landscape amelioration and to open up permanent viewpoints in the forest.


Landscape and recreation

Formal recreation is of low importance despite the forests being well used locally by the communities. Though the forests are a backdrop in the landscape of the Dulais Valley and highly visible, the broadleaf nature of the more gentle slopes of the Dulais Valley mean that all the larch felling of recent times has be absorbed well into the forest landscape and the overall impact has not been too dramatic.


Ancient Woodland sites

This is a small proportion of the forest area although previous management and planning has led to an overall increase in broadleaves in the second rotation especially in the Tawe Valley and on the lower slopes in Crynant Main Forest in the Dulais Valley.

This broadleaf expansion links in well with the Ancient Woodland remnants and helps to creative good connectivity between the native woodland in both valleys.


Other conservation and heritage considerations

  • Potential for butterfly conservation in mineral restoration area in Seven Sisters
  • Keep Sarn Helen clear of trees especially in boggy areas


The water catchments relating to this resource plan area are not acid sensitive and therefore do not require an acidification assessment.

Access and haulage

Reasonable access to all parts of the forest exists although some upgrading of infrastructure is required for timber haulage. Third party access exists in Seven Sisters, Nant y Cafn and Crynant Main is to access mining, utilities and Energy Delivery Programme projects.

Comments or feedback

If you have any comments or feedback, you can contact the Forest Resource Planning team at frp@naturalresourceswales.gov.uk


Related document downloads

Location map PDF [3.2 MB]
Forest types map PDF [2.9 MB]
Management systems map PDF [4.0 MB]
Thinning map PDF [3.0 MB]
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