Landscape-Scale Natural Regeneration (LSNR), a new forestry model for Scotland.
What is the issue?
The 2020s have been declared “The Decade of Ecological Restoration” by the United Nations, highlighting the need for every country to play its part in restoring the ecosystems on which we all depend. In Scotland, there is huge amount to be done. From drained peatlands to dredged sea-beds, canalised rivers to over-grazed woodlands, nearly all of our ecosystems are degraded. Of these habitats, the Forest Policy Group is best placed to advise on woodlands. We believe that allowing the restoration of native woodlands at scale, through natural regeneration, is a crucial task for the coming decade.
Paleoecologists agree that Scotland was extensively forested in post-glacial times, with temperate rainforest habitats on the west coast giving way to boreal pinewoods further inland (in the north of the country) and temperate broadleaf woodlands dominating further south. Since its peak extent c.5,000 years ago, a combination of climatic and anthropogenic factors led to a dramatic decline in Scotland’s native woodland cover. Pastoral and arable farming, as well as sporting estates in recent centuries, have prevented natural regeneration of remnant woodlands in many areas, inhibiting the ability of those woodlands to endure. Extractive practices like muirburn and extensive upland sheep farming have probably further reduced fertility in the last 200 years or so.
As a result, across large parts of the unenclosed uplands of Scotland, terrestrial ecosystems are locked into a deforested state. Herbivory, mainly from deer and sheep, remains sufficient to prevent natural regeneration and, as native woodlands fail to renew themselves, their distribution and extent continues (in places) to decline, enabling the further spread of species-poor grassland and heathland. In improved pasture, arable farmland and peri-urban areas remaining native woodlands are typically fragmented, tightly bound by fences, and surrounded by enriched soils that are prone to strong weed competition with young trees, whether planted or seedlings.
Continued loss of native woodland habitats is problematic ecologically, socially and economically. In the context of climate change and the rapid (global) loss of biodiversity it is especially undesirable. Scotland’s current native woodland cover is around 4-5% of the country’s land area, representing between a tenth and a twentieth of its original extent and around a quarter of the area under non-native, productive forestry. Of our current native woodlands, 62 % are highly semi-natural in appearance although there is no reliable data on what proportion have genuinely self- seeded.
In recent decades, there has been quite a lot of effort to restore remaining native woodlands, both by encouraging natural regeneration and by planting. As well as this, the area under native woodland cover has been extended significantly through the planting of new native woodlands, normally using grant aid. This native woodland creation programme is currently running at 3-5000 ha per annum under the Scottish Biodiversity and Forestry Strategies. So far, though, only a small proportion of publicly funded new (or extended) native woodlands has deliberately employed natural regeneration as its method of establishment. There have, however, been substantial areas of ‘accidental’ regeneration arising wherever grazing, browsing or burning pressures have ceased.
It is this lack of deliberate use of natural regeneration that we believe is problematic, because there is strong evidence to suggest that the most ecologically beneficial way to facilitate the expansion of semi-natural woodland is by enabling the process of natural regeneration to operate at a landscape scale. Such an approach would possibly be more cost-effective in the long run and, in many situations, could also be more carbon-friendly than planting. However, at the moment, this outcome is not being targeted specifically by Scottish Government policy or incentives, nor is it a clear priority for research.
Part of the problem is that there is no clear agreement on the benefits of, or role for, natural regeneration, as opposed to tree planting. There still exists a strong bias towards the latter in Scotland, perhaps due to a widespread preference for outcomes to be pre-specified and tightly controlled. To address this, the FPG believes that several things need to happen.
- An improved understanding of the pros and cons of natural regeneration in different contexts
- Our grant regimes adjusted to incentivise more natural regeneration
- A clear integration of natural regeneration with existing policy, to provide specificity about where and why it should be preferentially deployed
Natural regeneration within a remnant pinewood. Photo credit – Gus Routledge
For decades, ecologists and conservationists have been calling for greater use of natural regeneration to facilitate expansion of native woodlands and enable habitat restoration. In recent years, awareness of the merits of this approach has grown steadily, helped enormously by the efforts of some landowners to provide examples of landscape-scale natural regeneration (LSNR) on their estates.
Despite this growing awareness, the use of natural regeneration to facilitate ecological recovery is still limited to a handful of actors, who tend to pursue this approach out of an intrinsic, personal motivation rather than in response to external policy incentives. Yet the urgency of our environmental crises demands that the scale of our ambition in Scotland increases rapidly, and natural regeneration at a landscape-scale, if it is deployed effectively, offers an approach to woodland expansion and ecological restoration that is commensurate with the magnitude of the challenge we face.
This November will also see Scotland’s approach to land management scrutinised on the world stage. As hosts of the COP26, we need to be seen as leaders in climate action, harnessing the power of nature-based solutions wherever possible. The convening of the UN Biodiversity Conference (COP15) in China this autumn adds further impetus to this, and to finding integrated solutions that speak to the interrelated environmental crises we face.
Scotland’s emerging Regional Land Use Partnerships (RLUPs) provide another reason to strike now on the issue of natural regeneration. These entities will be well-placed to provide the regional targets and specificity that any approach to woodland expansion demands, and to help adjacent landowners co-ordinate their efforts to achieve scale and connectivity in regional nature-recovery networks.
Finally, and vitally in the context of our rapidly changing climate, natural regeneration provides an important mechanism for allowing our terrestrial ecosystems to evolve genetically, through natural selection. If it can operate across a variety of landscapes and altitudes, natural selection will grant our woodland ecosystems the space and scale they need to have the best possible chance of adapting to new and fast-changing ecological norms.
Across Scotland, we now have multiple examples of the success that can be achieved by enabling natural regeneration at a landscape-scale. These initiatives demonstrate many of the direct and indirect benefits a regenerative approach can deliver, including greater integration of land uses and land management. They also highlight the challenges involved and the large amount of human effort and intervention that is required, especially in the early stages of a natural regeneration project.
With many of the learnings from these pioneering schemes now in the public domain, there is a golden opportunity to consolidate the relevant information into a formal knowledge base and take LSNR mainstream, deploying it preferentially across far larger areas when native woodland recovery and expansion is desired.
Why is more LSNR desirable?
There are a broad range of social, economic and ecological motivations for enabling a much greater adoption of LSNR in Scotland, which go beyond the many public goods that trees and woodlands provide.
Looking first at the economic benefits, the Scottish Government has set ambitious woodland creation targets, which will rise to 15,000 hectares per year by the 2024/25 planting season. Currently, the majority of this woodland creation is comprised of introduced conifer species, with only around 3000-5000 ha of it earmarked for new native woodlands. Although there is no clear data on exactly how much planting or natural regeneration is happening, a very high proportion of the new woodland is being planted. Of the new native woodlands that are being created, few are adjacent to existing native woods. Meanwhile, a high proportion of our remaining native woods are unable to regenerate even where they are deer fenced due to high herbivore impacts within the enclosures.
Planting has numerous costs including tree procurement, ground preparation and, notably, deer fencing. Although natural regeneration can be unpredictable, when woodland is created successfully using this approach, the costs can be far lower because the seed is supplied for free and the ground preparation (if there is any) is normally less intensive. Crucially, if enabled at a landscape-scale in combination with sufficient deer control then less deer fencing is required. This has the potential to save public money, given that during 2015-2019 around £13 million was spent on deer fencing grants under the Scottish Forestry Grant Scheme. Of course, some additional public funding will be required to support a greater deer stalking effort but this is unlikely to exceed the amounts currently being spent on grant funding deer fencing, meaning the public purse could save money overall.
Ecologically, tree planting also has distinct drawbacks. Ground preparation disturbs the soil, leading to increased greenhouse gas (GHG) emissions, especially in areas with a significant organic horizon (i.e. peaty soils). The use of tree tubes or guards is also widespread and, with no current enforcement of their removal, leads to large quantities of plastic pollution in the countryside every year, with the pollutants eventually moving into watercourses as the tubes break down into micro-plastic particles.
Fencing out herbivores is also ecologically problematic. It results in segregated landscapes, with artificially low levels of grazing and browsing within exclosures and artificially high levels outside them. To enable natural regeneration at a landscape-scale, deer numbers must be reduced to very low densities, but their presence remains across the landscape meaning they continue to interact with the terrestrial ecosystems of which they are an integral part. The reduction in deer numbers is likely to have additional co-benefits beyond woodland expansion. It will decrease the impact of deer on peatlands, allow expansion of sensitive habitats like tall-herb communities and montane scrub, lower the incidence of road traffic accidents, reduce deer-related impacts on existing forestry and reduce the availability of host organisms for disease-spreading ticks.
There are also social benefits to enabling LSNR, given the increased stalking effort that will be required to reduce and maintain deer numbers at sufficiently low levels. With greater numbers of stalkers involved in deer management across Scotland, the contribution of that profession to sustaining rural communities will be strengthened, potentially boosting the employment opportunities for local young people, too. Venison production could also increase, providing a healthy and ‘low-carbon’ meat alternative to that produced through animal agriculture, as well as jobs throughout the entire ‘forest-to-fork’ supply chain.
Of course, the social benefits will be felt much more widely than this, by the people getting involved in making it happen and in the enhanced wellbeing of our citizens, who will enjoy a richer, more diverse environment.
Fencing on Jura enabling natural regeneration of birch woodland and willow scrub, habitats largely lost from the island due to grazing and browsing pressure from deer, sheep and goats. Photo credit – Tim Turner
The final (and often least extolled) advantage LSNR offers over tree planting is the biological and genetic diversity it offers. Natural (self-seeded) woodlands develop a subtler matching of tree and site producing ecological niches that cannot be mimicked in planted equivalents, with inter-species interactions boosting biodiversity in often surprising and unexpected ways. Furthermore, by reproducing sexually and over large areas, naturally regenerating woodlands will always stand the best possible chance of evolving in response to climatic and other stresses, leveraging their genetic diversity to engender resilience within their populations.
Although LSNR is perhaps most suited to extensive upland landscapes adjacent to existing native woods, there should be scope for more use of natural regeneration in lowland farmed and peri-urban areas, too.
How it relates to policy?
There are many interlinked policy and strategy aims and actions published by Scottish Government, which relate to or can be contributed to by LSNR of native woodlands, in documents such as the recent Environment Strategy 2020, Scottish Forestry Strategy 2018/19 and Biodiversity Strategy (2013-20), as well as the Land-use strategy.
These policies recognise the importance of integrated catchment-scale planning and action to restore natural ecosystem processes and diversity, all the while sustaining or rebuilding Scotland’s stock of natural capital and the ability of our environment to support life and all the value we as humans derive from it (e.g. clean water, fertile soil, wellbeing, etc). They also explicitly link restoration and expansion of ecosystems such as woodland and peatland to tackling climate change, both mitigation and adaptation.
The use of natural regeneration of trees is promoted in a priority theme in the Scottish Forestry Strategy called, ‘Increasing the adaptability and resilience of forests and woodlands’, which advocates:
‘Supporting forest design and silvicultural actions which increase the capacity of forests and woodlands to adapt to, and thrive in, a changing climate’; and ‘Maintaining and enhancing biodiversity, in particular by using the recruitment of natural regeneration and improving mitigation of the risks posed by invasive non-native species, deer and other herbivores.’
However, explicit targets in the Scottish Forestry Strategy to promote landscape-scale natural regeneration are not obvious. For example, in the theme ‘Expanding the area of forests and woodlands, recognising wider land-use objectives’, the Strategy recommends:
‘Supporting the creation of a range of types and scales of new forests and woodlands using native and other tree species for a range of purposes, including production of timber’, as well as ‘promoting development of green networks’ and calling for ‘improved guidance and co-ordination on key factors such as ground preparation techniques and seed supply for planting.’
But nowhere is natural regeneration specifically mentioned. That said, its use is perhaps implied in actions to, ‘Support landscape-scale habitat management to protect and expand the range of key iconic protected and priority woodland species’ and, especially, to, ‘Publish Scottish Ministers’ response to the Deer Working Group review including actions relating to forestry’, since the latter is key to reducing the high deer populations that often inhibit regeneration and expansion of native woods.
In short, although there are numerous Scottish Government policy aims that are explicitly or implicitly served by a much wider use of LSNR, few current actions or mechanisms are clearly aimed at directly promoting it.
Lowland woodlands that are well-used for recreation often exhibit natural regeneration. Here, silver birch, scotch broom and sitka spruce are all regenerating, adding structural diversity to the forest. The tendency of invasive species to self-seed means enabling natural regeneration should not be synonymous with a ‘hands off’ approach. Forest management is still required to achieve desirable outcomes. Photo credit – Matt Hay
What needs to be done?
Develop a national vision for ecological restoration and, within that, set out the aspirations for native woodland, including the key role of natural regeneration in its expansion. A strategic focus on natural regeneration methods is also needed to consolidate a LSNR knowledge base and address many of the practical aspects of its implementation.
Landscape-scale planning and co-ordination will be vital, especially for deer management, and this can build on existing land-use strategy, regional partnerships and green network mechanisms. Some considerations for a new policy on LSNR are:
i) We could aspire to always use natural regeneration (instead of planting) around semi-natural woodlands over a certain size, to promote semi-natural habitat networks, ideally linked to other ecosystems such as peatlands and wetlands. Exceptions would be needed for practical reasons, but a clear starting point like this would focus minds and galvanise action.
ii) We could also favour expansion of recently planted ‘new native woodlands’ through natural regeneration and, in the short term, improve the quality of existing woods of this type, which are often of limited species diversity and soon colonised by deer which inhibit the development of a richer biodiversity. We also need to contain the spread of non-native species like Sitka spruce into semi-natural habitats, and manage those non-native species that are already established in native woods. A variety of approaches according to situation will be needed for this.
iii) A key barrier that we will need to overcome is the reticence towards natural regeneration that is born out of the inherent uncertainty and often long-term nature of using this approach. To do this we will need more demonstrations, research and best practice guides, to improve the success and predictability of LSNR, but we will also need a shift in our collective mindset and policy mechanisms: to see these characteristics as beneficial and as part of allowing nature to ‘do its thing’ within managed limits.
iv) We should consider implementing long-term schemes, perhaps analogous to former forestry dedication schemes where the land could be covenanted to restoration. This could entail an annual payment for suitable management towards a long-term plan, which could be revised periodically with input and agreement from stakeholders and local communities. Different approaches would be needed in extensive upland, agricultural lowland and peri-urban contexts.
v) Land ownership and land reform issues need to be considered as well. There could be opportunities and also challenges from changes here; in some cases perhaps a more fragmented ownership pattern could make LSNR schemes harder to agree and sustain, but on the other hand community ownership might encourage more of this approach due to the long term buy-in required.
vi) Developing a strategic approach to natural regeneration should also include a genetic management strategy, which plans to conserve naturally regenerating tree populations and potential seed sources, at a sufficient scale across their natural range. Scotland should urgently increase our adoption of the pan-European framework for conserving in-situ tree genetic resources that was developed by a network of scientists and foresters (EUFORGEN).
This framework advocates for the selection and management of a network of Genetic Management Units (GMUs). Despite our very comprehensive system of designated sites (e.g. SSSIs, SCAs, etc.) and knowledge of native woodlands through the Native Woodlands Survey of Scotland, the only UK site selected for this framework so far is Beinn Eighe NNR.
Other short-term actions could include:
- Adjusting grant incentives to favour NR by allowing longer time scales and/or more flexible measures of success based on ecological and carbon outcomes
- Improving our understanding of the greenhouse gas and other impacts of tree planting versus natural regeneration or ecological restoration approaches
- A vigorous drive to reduce deer populations regionally to levels that allow natural regeneration
- A review of ‘where it works and where it does not’ to improve LSNR guidance and inspire more effort in those locations that are suitable
- Use the Native Woodland Survey of Scotland data to help develop a strategy for natural regeneration and native woodlands more widely, for example prioritising areas of high naturalness.
- Revise the Biodiversity Strategy (2013-20) to include a national vision for ecological restoration, which targets LSNR explicitly
- Use the Regional Land-Use Partnerships to integrate LSNR into land-use planning
There is both a strong need and a key opportunity right now to greatly increase the use of natural regeneration at a landscape scale. This blog has tried to outline why it is important to do this, for the ecological restoration of our land and ultimately for the wellbeing of our people. It has also highlighted potential economic advantages as well as the likely challenges that LSNR might produce, and what we should prioritise for early action. We hope this blog can stimulate readers, and we welcome any suggestions they may have that will allow us to refine our proposition for foresters, conservationists and policy-makers across Scotland.
Natural regeneration in Glen Feshie around an existing seed source. Photo credit – Matt Hay
 Native Woodlands Survey of Scotland 
 For example: Mar Lodge Estate [NTS], Glen Feshie (Wildland Ltd.), Creag Meagaidh NNR [NatureScot], etc.
 S. J. Rao : Effect of reducing red deer Cervus elaphus density on browsing impact and growth of Scots pine Pinus sylvestris seedlings in semi-natural woodland in the Cairngorms, UK
 Trees for Life Native Pinewood Survey – Publication forthcoming
 S. Pepper, A. Barbour & J. Glass  – The Management of Wild Deer in Scotland: Report of the Deer Working Group