Bog woodland is a conservation priority habitat type under the EU Habitats Directive and a very rare habitat type in the UK.
A distinct type of bog woodland consisting of sparse, open woodland of stunted Scots pines occurs on bogs in pinewoods in the Scottish Highlands. Other types, dominated by birch, goat willow, grey willow or alder grow on fen peat along the central flow lines of valley mires and in spring-fed fens within larger bogs.
The rarity of these habitats has limited the amount of research effort expended on them. Consequently they are poorly understood. While their conservation is a high priority, basic knowledge on how they function is badly needed in order to provide guidance on conservation management.
Age structure study of Scots pine bog woodlands
As part of the EU LIFE Wet Woods Project Forest Research studied four of the UK’s best examples of Scots pine bog woodland. Tree rings were counted using increment cores taken from the base of the trees. The age structure of sample plots in each woodland was obtained. The ground vegetation was considered alongside the woodland structures in interpreting the age structures.
We concluded that, although the sites had been rather disturbed by fires and peat cutting, open Scots pine bog woodland is not necessarily just a transient phase occurring as bogs become fully wooded but can be a long-lived natural habitat in its own right.
The results are summarised in the project report and were published in: A.R. Anderson and K.I.M. Harding (2002). The age structure of Scots pine bog woodlands. Scottish Forestry 56 (3) p135-143.
Review of the eco-hydrology of bog woodlands and alluvial woodlands
English Nature (now Natural England) and the Environment Agency commissioned a literature review and research needs assessment exercise on the eco-hydrological requirements of wet woodlands in 2004.
In preparation for reviewing water abstraction and effluent discharge licences under the Water Framework Directive, links between these water activities and protected habitats on which they impact needed clarification. Information was gathered on bog woodlands and alluvial woodlands. Little relevant published information on bog and alluvial woodlands was found but experts were contacted and unpublished data gathered also. This research highlighted the difference between bog woodland types across Britain
The impacts of various hydrological changes were inferred by attempting to characterise the water supply mechanisms operating in known examples of the habitat. Lines of research needed to fill the knowledge gaps were highlighted by the review.
The review has been published as English Nature Research Report Number 619: Eco-hydrological guidelines for wet woodland – Phase I.
Example of the hydrological vulnerability diagrams in the report
For further information about this work please contact Russell Anderson.