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The environment, our biosphere and all its resources is fundamental to all that human society does and the economy is the means by which we distribute those resources. Trees and woodlands are a vital part of our environment. They are important and diverse habitats invaluable in their own right, but they can also have impacts on other components of the environment and climate.
The Government has produced a biodiversity strategy for England “Working with the Grain of Nature”. Amongst other measures set out in the Strategy is the commitment to develop and support biodiversity partnerships in the English regions and at more local levels.
- public bodies' biodiversity duty -
The Natural Environment and Rural Communities Act 2006 requires all public bodies to have regard to biodiversity conservation when carrying out their functions. It is sometimes referred to as the ‘biodiversity duty’. It aims to raise the profile of biodiversity and embed consideration of biodiversity in decision making across the public sector.
- Lawton Report: aiming to deliver an enhanced
natural environment -
An independent review of England’s wildlife sites and ecological network was launched in September 2009. The review was chaired by Professor Sir John Lawton who, supported by a panel of 14 members, produced a report entitled “Making Space for Nature”, published by the Secretary of State for Environment, Food and Rural Affairs and Defra on the 24 September 2010. This review considered whether England’s collection of wildlife areas (both the legally protected areas and others) represents a coherent and robust ecological network that will be capable of responding to the challenges of climate change and other pressures. 'Making Space for Nature' made a number of key proposals, chiefly:
‘that the overarching aim for England’s ecological network should be to deliver a natural environment where: Compared to the situation in 2000, biodiversity is enhanced and the diversity, functioning and resilience of ecosystems re-established in a network of spaces for nature that can sustain these levels into the future, even given continuing environmental change and human pressures.
The report also recommended that this be underpinned by three objectives:
(1) To restore species and habitats appropriate to England’s physical and geographical context to levels that are sustainable in a changing climate, and enhanced in comparison with those in 2000.
(2) To restore and secure the long-term sustainability of the ecological and physical processes that underpin the way ecosystems work, thereby enhancing the capacity of our natural environment to provide ecosystem services such as clean water, climate regulation and crop pollination, as well as providing habitats for wildlife.
(3) To provide accessible natural environments rich in wildlife for people to enjoy and experience.
The East of England supports a rich and diverse natural environment with many rare habitats and species. This biodiversity is important as it benefits us all in so many ways. The quality environment allows the potential of a number of ecosystems to benefit and, in turn, they provide economic and social dividends through an improved quality of life.
- East of England's key environment challenges -
The key challenges for the East of England are:
- Increasing the extent of semi-natural woodland cover,
- Bringing more ancient woodland into active management,
- Creating woodland where it will link or buffer existing habitat,
- Better recording of heritage woodland resources,
- Better protection for veteran trees,
- Restoration of coniferised ASNW,
- More universal application of the UK Forestry Standard, and
- Encouraging traditional industries that will give economic purpose to coppice and wood-pasture systems
Here we examine the components of biodiversity and their various contributions:
- woodland's environmental contributions -
Woodland is an important element of landscape and vital for its role as habitat for a number of species of flora, fauna and fungi. Woodland forms an essential part of many Sites of Special Scientific Interest (SSSIs).
Trees and woodlands contribute greatly to the biodiversity of the East of England. Of greatest importance are those woodlands that are Special Areas for Conservation (SAC), Special Protection Areas (SPA), Sites of Special Scientific Interest (SSSI), or Ancient Semi-Natural Woodland (ASNW). ASNW has been continuously wooded since at least 1600, and consists of site native species of trees and shrubs. They are the closest to truly natural woodlands that exist in Great Britain, having been managed by traditional and sustainable means and, as such, are irreplaceable ecological and cultural assets. This region has a higher percentage of ASNW than the national average, and the designated woodlands underestimate the true resource as wood-pasture was generally omitted from the original list, as were all woodlands under two hectares in area.
- re-creating ASNW -
Ancient woodlands that have been converted from site-native to other species, generally conifers, are termed Plantation on Ancient Woodland Sites (PAWS). These woodlands frequently retain remnants of the original ancient woodland communities, including under-storey, ground flora and deadwood fauna. By careful and judicious restoration of these woods to site-native tree species, it may be possible to recreate the characteristics of ASNW.
- conifer plantations as SPAs -
The biodiversity interest is not limited however to these two woodland categories. The extensive conifer plantations of the Sandlings and Thetford Forest have been designated as SPAs due to their international importance for woodlark and nightjar.
- hedgerow's equally valuable -
Hedgerow and other non-woodland trees are also of great importance for biodiversity and landscape. In many cases they are under threat from agricultural intensification and climate change.
b. ContributionsTrees...increase biodiversity
Trees are a significant wildlife habitat, providing nesting sites for birds and supporting a wide range of insects that are an important food source for birds and other wildlife.
- A typical oak tree supports up to 5000 different species of invertebrates that will form the basis for a healthy food chain for birds and mammals.
- Stands of trees link the countryside along highways, waterways and railways, enabling it to be more porous for wildlife and, in time, adding to an area's biodiversity.
All woodlands provide habitats for a range of flora, fauna and fungi. Even small, recently established, woodlands within otherwise intensively cultivated land can be useful although their scope is limited by their isolation and, in certain circumstances, can harbour pest species. It is vital to consider the interaction and interdependency of woodland and other habitats (e.g. unimproved grassland, fenland and hedgerows). Trees and small woodlands can bring aspects of the countryside, particularly birds and mammals, into the heart of urban areas, where they can contribute to quality of life by bringing people into daily contact with nature.
- biodiversity planning -
Local Biodiversity Action Plans (LBAPs) are provided guidance to allow them to play their part in delivering UKBAP. Some LBAPs were developed ahead of the national Habitat and Species Action Plans (HAPs and SAPs).
A series of UK Habitat and Species Action Plans (HAPs and SAPs) have been agreed for nationally important habitats and species. A large number of these are relevant to woodland (40% of habitats and 30% of species).
The first set of Habitat Action Plans (HAPs) contained measurable UK targets to maintain, restore or create habitat, usually for the period 1996- 2010. A more comprehensive list of HAPs has now been extended to cover the period from 1996 to 2015. The relevant woodland related targets for the East of England are:
- habitat targets -
- Restore 3200 hectares of non-native plantations on ancient woodland sites to native woodland
- Create 6400 hectares of new native woodland
Woodpasture and parkland:
- Restore 40 sites of derelict wood-pasture and parkland to favourable condition
- Expand 12 sites of wood-pasture and parkland, in appropriate areas, to help reverse fragmentation and reduce the generation gap between veteran trees.
A football pitch-sized area of woodland removes a sack of potatoes weight of particulates in a year.
Source: Forest Research
- A research study estimated that doubling the number of trees in the West Midlands would reduce excess deaths due to particulate pollution by up to 140 per year.
Source: Lancaster University
A 2008 study by Lovasi et al founds that tree lined streets have been associated with a lower prevalence of asthma in children, even after adjusting for other factors. In the same year the Sustainable Development Commission reported that admissions to hospital linked to air pollution cost the NHS between 17million and 60million a year (Sustainable Development Commission 2008).
Trees...improve water quality
Trees act as natural filters that improve water quality
The water resource should not be divorced from the soil resource – indeed it is imperative that the soil is managed in an effective way in order to ensure delivery of sustainable water resource benefits (in terms of water quality, water supply and flood management). These types of ecosystem services need to be taken into consideration to ensure communities and industry gets the best from the assets available.
Woodlands help to:
- Modulate the water cycle,
- Affect biogeochemical cycles (including the carbon cycle),
- Buffer and reduce pollutants
Examples of water management and other tree related effects include: attenuation of downstream peak water flows, reduction in water temperature (and protection of fish populations) through shading by riparian woodland, reductions in soil erosion (which could become greater through drier summers and wetter winters), shade and reductions of ‘heat island’ effects in built up areas, and removal of pollutants.
- growing water demand -
The East of England is one of the fastest growing areas of the country in terms of population, with a resultant increasing demand on natural resources such as water. The impact of trees and woodlands on the future management of water in the region is likely to become ever more significant; particularly when viewed against climate change predictions. With the East of England being the driest area of the country and climate change predictions indicating that this is likely to get worse, the resultant demand on water will impact on all uses including domestic and agricultural production.
The Environment Agency, the body responsible for maintaining and improving the quality and quantity of water supply, has developed a number approaches to water management, including Catchment Abstraction Management Strategies and River Basin Management Plans.
- trees and water management -
Trees have an important and increasing role in water management. For water entering streams and rivers from agricultural land may be contaminated by fertiliser and pesticide residues, and the effects of soil erosion. Trees planted as permanent buffer strips along watercourses can help remove these pollutants.
Water abstracted from beneath forest areas tends to have much lower levels of contamination than that beneath agricultural land due primarily to the much lower levels of fertiliser and pesticide application to the crops and improved soil quality.
- trees and water use -
There is some debate about the quantity of water used by woodland in comparison to agricultural land. There is general agreement that deciduous woodland is largely inactive in water use until mid to late May, which allows for an extended period of ground water recharge. When in full leaf, however, there is no argument that woodland uses more water than grassland and most arable crops. It may be that replacing grassland or arable crops with trees could increase the overall water availability. Some tree species, including willow and poplar, have particularly high water demands, which may have a bearing on their future planting in areas where water may become an increasingly scarce resource. There is a need for further research into the relationship between tree species and water use.
Tree roots preserve the soil resource, while leaf mould can enhance it as compost, thereby offsetting soil erosion.
Woodland soils tend to have a structure that greatly enhances their ability to perform these functions compared to arable land. The lack of cultivation results in a more open texture, increased organic matter content and greater activity of soil fauna. The presence of tree roots tends to make the soils more stable and less prone to erosion. The tree canopy and litter layer reduces the impact of heavy rain thereby limiting the likelihood of erosion due to flash flooding.
- trees as shelterbelts -
The East of England has extensive areas of soils that are very vulnerable to wind and water erosion (sands and peat) and compaction (heavy clays). The establishment of shelterbelts or hedgerows can reduce wind erosion by moderating wind speeds and acting as physical barriers against which blown soil accumulates. Riparian woodland prevents water-eroded soil entering rivers and streams.
In areas with heavy clays, woodland soils tend to suffer less compaction in comparison to agricultural uses due to lower levels of ‘traffic’ and other negative effects. The exception to this norm may arise from tree harvesting and extraction involving unsuitable machinery in wet conditions.
Consideration of soil suitability for woodland expansion, and protection of soil function and diversity in management, is central to the delivery of all other benefits. Good soil management is the foundation for the healthy functioning of the region’s woodland.
An increasing risk of flooding is one of the most firmly predicted impacts of climate change. With flood events apparently on the increase (it is estimated that 125,000 households in the region are susceptible) the issues of flood prevention and mitigation measures are becoming increasingly important. It is becoming clear that that there are other approaches to solving the problem than by building ever-higher flood defences.
- trees and flood control -The emphasis is turning to pursuing more sustainable means of flood control. One option is for woodland to help alleviate damaging floods, particularly though the planting or restoration of floodplain and riparian woodland in association with the development of more natural-river flows. It has been shown that these types of woodland can retain more water on the floodplain, principally due to the trees, ground vegetation and fallen deadwood forming a significant physical barrier to flood flows:
Trees can act as 'absorbent wood dams' attenuating water run-off after downpours
Woodland higher up the catchment could also have a role in reducing peaks and troughs in flow rates (by reducing infiltration and acting as ‘buffering’ water storage). There is also the attraction of other benefits floodplain woodland provides, including enhanced; protection of other important wetland habitats, recreation, more attractive landscape, greater biodiversity, and improved water quality.
- trees and floodplains -
Opportunities to restore floodplain woodland and to assess its ability to aid flood control, however, are hampered by a number of related concerns. These include the threat of such woodland actually increasing flooding due to backing-up of floodwaters upstream and the blockage of downstream bridges and culverts by woody debris. The risk of such problems arising depends on local factors such as the presence of housing and transportation links, and the capacity and location of flow controlling structures.
Other constraints on planting within floodplains include:
a. Maintenance of appropriate access to the main river channel,
b. Protection of buried archaeology and earthwork,
c. Maintenance of a navigable channel for boat traffic and
d. Making sure that summer water flows will not be significantly reduced
e. Preservation of historic water meadows and other riverbank features and land uses.
- limited numbers of sites for floodplain woodlands -
The East of England is characterised by a high proportion of the area being flood plain, but the built-up nature of much of this, plus the large number of potential constraints mean that there are likely to be relatively few locations where extensive areas of floodplain woodland could be appropriate. There could be, however, considerable scope for planting a network of smaller riparian and floodplain woods, which collectively could aid downstream, flood control.
Recent developments in information technology and river modelling mean it should now be possible to determine the most suitable location of floodplain woodland. Geographical Information Systems provide a means by which suitability maps could be produced. Such maps would indicate the scope for future planting in river catchments and thus help to determine the extent to which woodland could contribute to flood control in the future.
Trees and woodland help to define the landscape and also provide the backdrop for our villages and towns in the East of England. The value of landscape in the East of England is estimated to worth £124million per year, this is based on the value that people are prepared to pay for a view of woodland.
- the value of landscape is £124million per year -
Perhaps the most widespread public benefit of trees and woodlands is their contribution to landscape. Attractive landscapes benefit the general quality of life of local residents, can influence inward investment and underpin a significant part of the tourism industry.
Whilst there are some places where attractiveness is partially dependent on the absence of tree cover, landscape evaluation techniques generally view trees and woodland as major positive components. Ancient woodlands are important features in a number of areas; existing plantations, for example in Brecks and along the Greensand Ridge, are of major regional significance; tree presence is critical in terms of defining certain landscape types, such as parkland, river valley with wet woodlands and the carr woodland of fen edges; woodland and hedgerows can be of considerable importance as historic features, while farmland shelterbelts/tree lines and wooded areas are of importance in giving character to the more open parts of the region; there are several specific landscape types affording opportunities for new/regenerated woodland areas.
- diverse scenic quality -
The scenic quality of the East of England is very diverse, The Landscape Forum in the East of England (Landscape East) which has been in existence since spring 2004, has over the last few years commissioned studies including the joint development of a Regional Landscape Framework based on an agreed typology. www.landscape.org.uk
- Environmental Impact Assessments vital -
To protect the landscape from damaging changes Environmental Impact Assessments are required for new woodland planting or clearance that may have significant environmental effects. This ensures the effect on the landscape and biodiversity can be taken fully into account in the decision-making process and opportunities taken to mitigate adverse impacts.