ECOS 39 (1): Continuous Cover Forestry and Rewilding

Better understanding of Continuous Cover Forestry could steer much UK forestry practice towards the wider range of conservation practices CCF embraces. 

Changing mindsets in forestry

Forestry plantations from the 1960s still shape many opinions of forestry in Britain today. Dense, dark, mono-specific stands, depleted of wildlife are currently being challenged by today’s new foresters. Forestry is as essential today as it was in the 1980s, with the World Wide Fund for Nature’s (WWF) living forest report showing an increasing need for commercial forestry to supply a growing demand for wood products thus preventing further exploitation of natural forests. The dogmatic clear fell (CF) forests of the 1960s are being challenged by an environmentally conscious silvicultural method.

Continuous Cover Forestry (CCF) is a holistic management approach that maintains constant forest cover. The use of selective felling and natural regeneration to replace felled trees produces complex forests and removes the need for clear-felling.⁶ The resulting forests are structurally diverse, both horizontally and vertically. CCF has been practiced for many years across Central Europe. CCF principles have been successfully used in native UK woodlands, however, the remainder of the article focuses on non-native, commercial forestry plantations. Previous research has shown that half of all conifer plantations in the UK are suitable for transformation to CCF, however only 5% are being managed using this approach. Studies have shown a conversion of commercial forestry to CCF principles would result in higher wildlife value and a wider range of Ecosystem Services (ES).⁵ Thus CCF has the potential to facilitate rewilding projects, as a result of its aesthetic appeal, use of natural forest processes and ability to thrive in combination with a wide range of fauna.

Continuous cover forestry and policy

In recent years there has been a policy drive for more sustainable silvicultural systems within Wales and Scotland. Wales has aspired “to convert at least half of the National Assembly woodlands to continuous cover forestry (CCF) by 2020, where practical” (Woodlands for Wales, Forestry Commission, 2001). This has since been diluted by changing the wording, replacing CCF with “sustainable silvicultural methods” in the subsequent Woodlands for Wales reports.       

The shift in policy can partially be attributed to the work of the Continuous Cover Forestry Group which is affiliated to the wider organisation Pro Silva, which promotes CCF. The encouragement of CCF should be more widely supported by a diverse range of groups from nature conservation organisations working at landscape scale to maximise wildlife value, to recreational user groups which prefer using more structurally diverse forests.² In Britain the Woodland Trust is becoming increasingly interested in using CCF to restore plantations on ancient woodlands sites (PAWS). An example, is the recently acquired Allt Boeth which is a PAWS in Cwm Rheidol in Wales, where the Woodland Trust is continuing the work carried out by the previous owner, using CCF techniques to aid restoration of the site back to native broadleaf. CCF can work hand in hand with the best practice ‘gradual approach’ to restoration, aiming to protect and enhance ancient woodland remnant features. Despite CCFs diverse application there are three issues preventing its wide spread application as summarised below.

Factors hindering the uptake of CCF: 

Practical level barriers. A lack of experience managing CCF systems in Britain, means foresters are apprehensive about using them. Additionally, machine operators aren’t familiar in working in these types of systems and will need additional training. To overcome these issues SelectFor, a CCF consultancy is training foresters and machine operators in CCF methods for lowland and upland forests. 

Unfavourable policy. The current agricultural grant system is based around CF systems, with grants for restocking and ground preparation artificially enhancing the competitiveness of CF systems. With the anticipated shake up of the grants system post Brexit, it is hoped that the new system will be less CF centric and that CCF can capitalise on new grants such as Payments for Ecosystem Services. 

The misconception. It is well recognised from literature and case studies that lowland forests can be positively managed under CCF, however a misconception remains that CF forestry is the only profitable management option for large upland Sitka plantations. Evidence from Bryn Arau Duon, a 702 hectare upland forest managed by SelectFor, is proving otherwise. Bryn Arau Duon is a commercial forest managed for profit and has been undergoing, for the last 18 years, a transformation from an even-aged forest to an irregular forest. The transformation involves a phase of graduated density thinning followed by selective felling of a proportion of the original trees, allowing the next cohort of trees to naturally regenerate under the irregular canopy. This results in the forest becoming more structurally diverse, supporting species such as red squirrels, pine martens, a wide range of bird species and a growing population of roe deer.

Continuous cover forestry and rewilding

Any large re-wilded area in the UK today will need to be surrounded by a buffer zone, unless of course it is fenced. Buffer zones are defined as “areas peripheral to a protected area, where restrictions on resource use and special development measures are undertaken in order to enhance the conservation value of the protected area”. Land uses for buffer zones may need to link farming methods with rewilding. However, very little has been discussed with regards to forestry.

By promoting wildlife and natural processes alongside timber production, CCF is one of the most suitable land uses for buffer zones. Highly structured stands of CCF have been proven to provide a high level of income which is more evenly distributed over time compared to CF.³ Growing trees for longer and harvesting them at their optimum size produces a better-quality timber, while reducing the volume of juvenile wood. In conjunction with high quality timber, CCF management has been found to be beneficial for wildlife value. Research shows that CCF supports a higher number of wood ants, more vascular plants, bryophytes and more assemblages of bird species in comparison to CF. CCF is able to continuously support an enhanced community of mature forest bird species like lesser redpoll and also certain scrub associated species such as blackcap, which usually occur in the early growth stage of CF.¹                                                                                                 

While studies have shown that CCF generally supports more wildlife than CF, CCF could potentially benefit from reintroductions of Eurasian lynx and wild boar. Wild boar presence benefits CCF through fulfilling a key ecological niche by providing conditions for tree regeneration, through their disturbance of the forest floor and through seed dispersion. In some cases, gaps which are created through felling can provide environmental conditions for a vigorous spread of bracken, which can severely inhibit tree regeneration. The return of the wild boar would be beneficial in this respect, by breaking up rhizomes which would aid the re-establishment of trees. The benefits of using pigs to control bracken has been proven in Langley Wood NNR. Pigs were found to reduce the density of bracken, facilitating higher levels of tree regeneration, in comparison to Asulam and rolling, in a bracken dominated clear-cut.

The explosion of deer populations across the UK has hampered natural tree regeneration. The constant regeneration of trees in CCF forests is vital for long-term sustainability and profitability. Too much deer browsing is considered a serious threat to the resilience of the stand. In contrast, too little or no deer browsing can result in excessive weed growth that restricts tree regeneration, this requires enrichment planting and the associated protection and maintenance, which is a costly intervention. Through the introduction of  predators like the lynx, it is hoped that an equilibrium will be reached, with enough deer browsing to control excessive bramble growth, but not enough to prevent regeneration at all, allowing the next cohort of trees to succeed. Mutual benefits from reintroduction and reinforcement projects can be seen in Mid Wales where the release of pine martens is hoped to assist with controlling grey squirrel populations. This should in turn reduce ring barking, enhancing the appeal and scope of integrating broadleaf trees into plantation mixes.

CCF’s potential

Not only can CCF forests support and harbour high levels of wildlife, coupled with economic profitability, but they can also offer opportunities for recreational activities with limited resource extraction, such as foraging (eg. mushroom picking and berry picking) and hunting. There is also the possibility of using CCF areas to control animal populations including by preventing them from over spilling into more sensitive areas, such as arable farming. This offers the opportunity to include other land-users such as hunting groups to participate in the discussions relating to re-wilded areas and further widen the appeal and scope of rewilding. Tackling the barriers to CCF could steer much UK forestry practice towards CCF and the wider range of conservation practices it embraces. 

References

1. Calladine, J., Bray, J., Broome, A. & Fuller, R.J. (2015) Comparison of breeding bird assemblages in conifer plantations managed by continuous cover forestry and clearfelling. Forest Ecology and Management. [Online] 344, 20–29. Available from: doi:10.1016/j.foreco.2015.02.017.
2. Edwards, D.M., Jay, M., Jensen, F.S., Lucas, B., et al. (2012) Public Preferences Across Europe for Different Forest Stand Types as Sites for Recreation. Ecology and Society. [Online] 17 (1), art27. Available from: doi:10.5751/ES-04520-170127 [Accessed: 8 November 2017].
3. Kerr, G., Mason, B., Boswell, R. & Pommerening, A. (2002) Monitoring the transformation of even-aged stands to continuous cover. [Online] (iii), 12. Available from: http://hdl.handle.net/10242/38991.
4. Malcolm, D.C., Mason, W.L. & Clarke, G.C. (2001) The transformation of conifer forests in Britain – Regeneration, gap size and silvicultural systems. Forest Ecology and Management. [Online] 151 (1–3), 7–23. Available from: doi:10.1016/S0378-1127(00)00692-7.
5. Mason, W., Kerr, G., Simpson, J. & Britain, G. (1999) What is continuous cover forestry? Forestry Commission Information Note. [Online] 1–8. Available from: doi:10.1007/978-94-007-2202-6.
6. Pommerening, A. & Murphy, S.T. (2004) A review of the history, definitions and methods of continuous cover forestry with special attention to afforestation and restocking. Forestry. [Online] 77 (1), 27–44. Available from: doi:10.1093/forestry/77.1.27.

GUY BENNETT

PhD researcher in the Earth Observation and Ecosystem Dynamics Research Group at Aberystwyth University. 

Contact the author

PHILIPPE MORGAN

Retired president of Pro Silva and chairman of CCFG. He is chairman of the Irregular Silviculture Network and director of Sustainable Forest Management and of SelectFor, Experts in continuous cover.