Kielder Forest: forest design, management and red squirrel conservation (completed 2003)
Peter Lurz and John Gurnell
The partnership between Forest Enterprise (Kielder Forest District), Mammals Trust UK and the Universities of Newcastle and London (QMUL) was highly successful and a background on the project and a summary of its outcomes is given below.
Project background and achievements:
Kielder Forest and Reservoir
Kielder Forest District covers more than 500 km2 in the north of England. It lies within the counties of Cumbria, County Durham and Northumberland and extends to the Scottish borders. The District contains more than 50 000 ha of forest, mostly Sitka spruce, Norway spruce and Lodgepole pine, and the forest holds the largest remaining red squirrel population in England. Most of Cumbria, County Durham and parts of Northumberland have already been colonised by the alien North American grey squirrel, and the threat to the red squirrels in the region is clear. It is therefore vital to manage and maintain a favourable conifer forest for red squirrels in which preferred grey squirrel habitats such as oak woodlands are few and absent from key areas. The Newcastle University and QMUL approach for assessing the forest and its management for red squirrels was seen as crucial to the development of a viable conservation strategy for red squirrels in northern England.
Our objectives at the outset of the project were to:
- identify areas of Kielder Forest District that are most suitable for red squirrels;
- identify those areas that are most vulnerable to grey squirrel incursion;
- assess how the current forest management design plans will affect both (a) and (b) in the future;
- develop a long-term management strategy based on forest design plans and management prescriptions that will maximise the probability of the survival of red squirrels within the Forest District;
- establish a long-term, squirrel monitoring programme within Kielder Forest.
We developed computer models to simulate the life histories of individual red and grey squirrels in forest landscapes. These models were combined with the electronically digitised forest design plans and used to explore potential outcomes of harvesting and replanting strategies in relation to red squirrel population viability. The approach therefore allowed us to assess the impact of different forest management objectives for a real forest landscapes on an endangered species.
A working group comprising Forest Enterprise, QMUL and Newcastle University was set up to facilitate an iterative process to identify the optimal management strategy for red squirrel conservation in relation to forest design. A liaison group was also formed to link the conservation efforts of the working group with all regional activities and organisations. This group involved English Nature (Cumbria and Northumberland), Northumberland Wildlife Trust, Northumberland National Park, Red Squirrels in South Scotland Project, MOD Otterburn and the Forestry Commission. Regular meetings were held to discuss results and potential conflicts of optimising forest design for red squirrel conservation with other conservation interests.
The results of the modelling predicted that the current red squirrel population in Kielder Forest is stable with an average of 8,000-9,000 adults (reaching up to 16000 in good years) for both the current composition and the proposed restock scenario.
The western part of the Kielder Main Block (core area of Kielder Forest) is most favourable for red squirrel management given current forest design and felling plans. It was also predicted that the suitability of the forest for red squirrels will change through time with the eastern part of the main block becoming progressively more suitable as the age composition and restock scenario (>2022) change.
Within the Cheviots’ region, Uswayford and Kidland Forest are also suitable sites for red squirrel conservation. These currently support a small populations of red squirrels but are surrounded by a large buffer area of moorland which may preclude them coming into contact with invading grey squirrels. We advised that the two forest areas should be linked and kept free of large seeded broadleaf plantations. Decisions on future restock plans and their success for these two areas will require consultation with other stakeholder organisations such as the National Park, MOD, Tilhill and the Wildlife Trust who manage areas within the forests or in the buffer zone around them.
Both the western part of the main block of Kielder Forest and Uswayford and Kidland would be the most suitable areas for red squirrel conservation in the District if future grey squirrel spread is considered.
Analysis of the likely spread of grey squirrels suggests that there are three routes of invasion into the forest district – Solway, north Tyne valley and area north of Uswayford and along the east coast of Northumberland.
In Kielder itself grey squirrel carrying capacity is likely to increase by over 50% in the long term if a proposed deciduous planting proposals would be implemented. There is therefore a need to carefully consider broadleaf tree species mixtures and in particular the oak component and their distribution in areas managed for red squirrels. We recognise in undertaking this work that there are significant gaps in our knowledge on grey squirrel habitat use, fecundity, mortality rates and behaviour in spruce plantations and more field research on grey squirrels in these habitats is required.
The present and future distributions of grey squirrels indicate that the spread of squirrel parapoxvirus (SPPV) infection into Kielder Forest is a serious concern for the future. There is already a risk of SPPV spreading north to Scotland from Cumbria along the Solway near Carlisle, Longtown, Langholm as well as into Dumfries and Galloway where the findings suggest a continuous presence of grey squirrels. We recommend that management options to limit the impact of SPPV on red squirrels in Kielder Forest District and a contingency plan should be researched as a matter of urgency.
Project promotion and outcome: The project was launched with a major press event involving invited guests at Kielder Castle in spring 2002 (press articles in The Journal, Sunderland Echo, Northern Echo, Newcastle Journal, Financial Times and Observer as well as regional BBC TV). The management approach and findings were promoted with a public University lecture in Newcastle (February 2003), at an international Tree Squirrel Colloquium (Ford, Northumberland May 2003) and a press event at the end of the project which again received regional and national attention (Journal, Northern Echo, Daily Telegraph, Financial Times), local TV coverage (Tyne-Tees TV).
As a direct result of the close collaboration and project findings, Forest Enterprise has agreed to:
- manage the whole of the main block of Kielder forest as well as Kidland and Usway Forest in the Cheviot areas for red squirrels;
- avoid planting oak within the core of Kielder Forest and the Kidland, Uswayford complex, except in specific circumstances;
- base native woodland plantings in the future on pioneer species such as birch and rowan and allow for a long-term natural succession of large seeded broadleaf species;
- maintain where possible lodgepole/Sitka spruce mixtures as well as areas of Norway spruce since these provide a dependable food supply for red squirrels;
- maintain a long term monitoring project in the Cheviot areas to monitor red squirrel population changes with regard to altered forest management prescriptions.
The project was undertaken by Peter Lurz and Steve Rushton at the University of Newcastle upon Tyne, NE1 7RU and John Gurnell, and was funded by Mammals Trust UK and Forest Enterprise, Kielder Forest District.