People have been planting trees for centuries, and for a variety of reasons. During Roman times fruit trees were collected and planted together to create orchards. During the 18th century, plantations of oaks were established for future ship building needs. Around the same time trees were planted to create beautiful landscapes across country estates. After the First World War, trees were planted on a large scale to secure a domestic source of timber.
Today, tree planting is very much associated with environmental protection and recovery, and for good reason, considering how down the centuries the loss of tree cover has been one of the most visible signs of ecological decline. Expanding tree cover can achieve a wide range of benefits and is now a high profile priority for Government in its mix of goals and targets linked with reversing environmental decline.
This week is National Tree Week, so the perfect moment to stand back and ponder what expanding tree cover might mean for the country, and how best to make the most of the opportunities at hand.
With a range of valuable benefits in mind, it is perhaps no wonder that Government has adopted an ambitious target for expanding tree cover and will be using that to advance other goals, including the delivery of a new Nature Recovery Network as set out in the 25 Year Environment Plan.
This is all to be welcomed, but what sort of trees do we want, where and why? A good starting point in finding answers is to be reminded of what trees can do for Britain. Recently, there has been (with good reason) a strong focus on catching and storing carbon, thereby helping in our response to the climate change emergency. This is of course a pressing reason, but there are many others. These include the creation of wildlife habitat, making landscapes and cityscapes more beautiful, helping to keep rivers pure, reducing flood risk, creating spaces for people to enjoy, cleaning the air and of course producing wood.
That is a valuable range of benefits, and Natural England agree we should pursue them through increasing woodland and tree cover by at least 20% by 2060. In pursuing such a stretching goal, we should be guided by three interconnected principles: first, to select the right trees, second to establish them in the right places and third for them to be there for the right reasons.
All types of woodland have value, but I believe that those dominated by native broadleaved species generally provide the most benefit for wildlife and people.
Native woodlands support a quarter of the UK’s priority species and those with a diversity of tree species are more resilient to disease. Using non-natives, by contrast, both in woodlands and individual trees, often supports fewer wildlife species and can increase the likelihood of pest and disease problems. And how they grow in landscapes can also be important.
The words ‘tree’ and ‘planting’ have become so familiar together that sometimes the very positive role that can be played by natural regeneration is overlooked. While increasing tree cover via planting of young trees and seeds is a necessary step in creating new woodland, natural establishment can also make a substantial contribution to achieving tree targets. Natural regeneration can for example be a viable strategy for linking existing (ancient) woodland patches, harnessing the natural dispersal of seeds in creating new tree cover. The natural expansion out from established hedgerows to create corridors of scrub and woodland can also be a useful approach in some landscapes.
The result is often more structurally complex habitat than a plantation, with greater wildlife value and an ecosystem better adapted to local environmental conditions. It also reinforces a distinctive sense of place, whilst reducing pressure on the supply chains of young trees (many young trees are presently imported from abroad, thereby increasing disease risk), reducing plastic use and being less costly.
Having said this, there are well-founded concerns about the impact of climate change on trees, prompting debate about how we should plan tree cover for the future. There is a suggestion that we should introduce non-native species, ones that are better able to cope with warmer conditions and different seasonal patterns. Whether this might be a wise choice will be informed by the intended use of the woodland, but where Nature recovery and amenity value are primary objectives, then Natural England suggests that using native species of local provenance will most often be the best option, and with natural regeneration of woodland where appropriate.
Trees can bring a wide range of benefits in a variety of places. One location that is gaining particular interest at the moment, however, is next to rivers and streams. Establishing new woodland adjacent to water courses, including through natural regeneration, can amplify the benefits of new tree cover, and sometimes over long distances.
For example, woodlands established in the headwaters of a river system can reduce the amount of farmland nutrients and soils escaping the land into rivers, thereby improving water quality, including far away in estuaries. The same woodlands can sometimes help to reduce downstream flood risk. Joined up planning and the targeted use of incentives can really make the most of these far-reaching advantages, for example through combining different budgets to reduce floods, increase wildlife and cut pollution, so that they achieve more together than they could when spent in isolation.
If wildlife-rich woods are also established close to where people live, then a wealth of health, wellbeing and other social and cultural benefits can be won, and this in turn can really help with ambitions for levelling up. For example, our Monitoring Engagement with the Natural Environment study has revealed how children from deprived backgrounds are much less likely – by 20 percentage points – to spend time outside than those from affluent ones. By establishing new woodlands in deprived areas, more opportunities for deprived communities to enjoy those health benefits would be created, whether they come through opportunities for tree climbing, hide and seek, or harvesting fruits and nuts, or simply enjoying quiet contemplation.
While we rightly embrace with great enthusiasm the prospect of much more woodland and tree cover, we need to ensure this does not come at the expense of sensitive landscapes or other important habitats, particularly as the twin challenges of climate change and biodiversity loss are so tightly interwoven. Priority open habitats, such as heathland and ancient meadows, are vital for their unique wildlife, which is why they have restoration targets under the government’s 25 Year Environment Plan. Enabling woodlands in those areas might catch carbon, but would cause wildlife losses, and is why Natural England urges caution.
A similar point can be made about peat soils and associated habitats, which have long been subject to afforestation. Peat is a most precious resource, both in terms of its ability to support important wildlife habitats and for carbon storage. It is now accepted that peat soils of any depth, along with their associated habitats, should generally be retained and, where degraded, restored to avoid carbon release and enhance sequestration. This will usually mean avoiding the deliberate establishment of tree cover on such habitats.
We believe that the best way to ensure new trees grow in the right places is to use the framework of the Nature Recovery Network and associated Local Nature Recovery Strategies, to plan where in the landscape trees and woodlands can deliver the widest range of public and nature benefits. Not all trees can or will contribute to the NRN, but it will help identify where they could bring most benefit or, conversely, where they should be avoided. In the context of the NRN, I believe particular attention should be paid to establishing new woodland along rivers and streams.
The right reason
The type of woodland created, the mix of tree species within it, its design (including any access) and management will depend on the opportunities and needs in particular of localities and landscapes, and on the preferences and priorities of land owners and managers.
All trees and woods - whether planted for amenity, flood prevention, timber or Nature – catch and hold carbon. The difference in how much carbon they lock up, and over what timescale, can be as much down to the location, management and fate of the harvested wood product as the tree species. For this reason it is important that we focus on delivering the widest range of societal benefits from new publicly-funded woodlands and trees, and are not tied to overly simplistic carbon logic.
Broadleaved species typically store more carbon per unit of timber production than conifers, partially offsetting the effects of their slower timber production rates. Some, such as birch, grow particularly well in the short term; others such as oak can store carbon for the long-term if the timber is used for a long-term purpose, or the trees are retained in the landscape in perpetuity (Lord Nelson’s flagship, HMS Victory, which rests today at Portsmouth Harbour, still holds carbon captured from the atmosphere longer than 500 years ago).
Agroforestry, in which trees or shrubs are grown alongside crops or pasture land, offers significant potential for increasing the number of trees in our landscape by integrating trees into farming systems. Although there are a number of barriers to this at present, the Agricultural Transition Plan, which takes farming in a new direction as we leave the European Union, provides a clear opportunity.
The potential benefits to farmers are numerous: strategic tree planting can significantly reduce the amounts of soil, nutrients and pesticides being washed into rivers. Joining up the planning of new woods with catchment sensitive farming thus presents a major opportunity. Those same trees can also provide income via wood products, leisure and the capitalisation of public benefits such as carbon sequestration.
These benefits will depend on trusted, expert advice to land managers, which Natural England has shown it can provide, working closely with Defra and colleagues at the Forestry Commission.
Increasing the nation’s tree and woodland cover, if channelled in the right way, could leave us with more attractive, wooded landscapes that help us meet our climate and Nature recovery goals while providing a host of vital additional services for our society and economy.
The opportunity is huge, so long as we can get the right trees in the right place – and for the right reasons.