November General Notes. Tree Protection. Tree Protection and New Development Guidance Note

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1 Tree Protection and New Development Guidance Note November 2006 General Notes The retention and planting of trees within a development can add to the character and aesthetic value of a site whilst maintaining local distinctiveness and providing habitats for wildlife such as birds and bats. Trees also filter noise, soften and screen buildings, provide shade, create privacy and hide or emphasise views. However, if not considered properly in new development, trees can not only cause nuisance for people and damage buildings, they can also be subjected to damage through unsympathetic construction techniques and design. This guide is designed to aid developers in the design of new developments and to provide suggestions for the protection of trees during construction. It should be noted that the County Planning Authority is responsible for applications for proposals that relate to the functions of the County Council (for example, applications for schools and social services facilities). The guide may also apply to minerals and waste applications. Tree Protection Trees can be protected in various ways: Tree Preservation Orders (TPOs): TPOs are designated and managed by the local planning authority (in the case of Devon by the District or City Council). Anyone who fells or undertakes unauthorised tree works on a tree protected by a TPO can be prosecuted. Penalties vary but if convicted in a Crown Court unlimited fines can be incurred. Conservation Areas: Trees of a certain size in Conservation Areas are also protected. Anyone, including the owner, wishing to carry out work on such a tree must give six weeks notice to the planning authority (District or City Council). Felling Licences: If a tree is of a certain size and the volume of timber produced from its felling is above certain thresholds a felling licence will be needed 1. No action can be taken until this licence has been granted. 1 The Forestry Commission administers felling licences and should be contacted with regard to whether a licence is required. Page 1 of 5

2 Previous Planning Permission: The site could be subject to a previous planning permission with particular restrictions regarding trees. This could affect the new development and the removal of trees on the site. Previous planning permissions should be investigated through consultation with the County Council. Property Covenants: The site could also be subject to property covenants in relation to the protection of trees so deeds should be consulted. Pre-application A land survey will include the location of all trees, shrubs and hedges. It will detail the levels of a site and the location of trees on adjacent sites which affect, or may be affected by, development; for example any trees within the distance of half the tree s height from the boundary of the site should be considered 2. A subsequent tree survey records relevant information regarding tree characteristics including age, condition, species, likely life-expectancy and surgery needs of the trees together with details of height, width of the crown and depth/span of the root system. The survey concludes with a British Standard colour grading to outline the value of the tree which goes some way in deciding its future. Design Considerations for Developments Overall site design should take into account the landscape and tree surveys and should be based on the need for particular zones around trees (Fig.1): Protected Zone: a fenced off area around the tree to be retained to eliminate tree damage during development. The size of the protected zone is either the distance of the crown spread of the tree (the width of the tree at its widest) or half the height of the tree, whichever is the greater. This zone must be considered during all development. Buffer Zone: a notional area around the tree beyond the protected zone in which inhabited buildings should not be located. The designation of this area should acknowledge future growth of the tree and thus will vary in size. The buffer zone ensures that buildings are not too close to trees which may starve them of sunlight (particularly if the tree is on the southern side of the building) and also means that less debris will fall on the buildings. This also benefits the tree as it saves them from over zealous pruning as a result of proximity to buildings. Constructions such as sheds without foundations, or driveways may be suitable in this zone. 2 For example, if a tree is 10 metres tall, it should be considered in the tree survey if it is within 5 metres of the site boundary. Page 2 of 5

3 Landscaping Zone: This is a zone to be used for open space and planting. This area should be protected during construction to guarantee that the soil is suitable for its subsequent use; for example, if this area has been designated for planting, the soil structure must be protected from compaction to allow plants to flourish. This zone will be more relevant in the design of larger developments with large amounts of open space. Tree Trunk Protected Zone Buffer Zone Fig.1 Landscaping Zone Layout should incorporate newly planted trees and acknowledge the location of existing trees on the development site. Development design should also recognise that, if unsuitably located and chosen, trees can cause nuisance; sufficient space should be provided between buildings and trees. This will ensure that trees do not cast unacceptable shadows (particularly if the tree is to the south of the building), and that root growth does not exert undue pressure on foundations or paved areas. Advice should be sought when considering the role of trees in a new development. When planting new trees or saplings particular attention must be given to the species of the tree-large species such as oak and ash are not suitable for small areas but help define large open spaces. Species selection should largely be governed by matching new additions to indigenous species already present and by recognising site characteristics such as soil type and aspect. Planting should occur in the first planting season following construction to ensure suitable growing conditions. Planning permission often specifies conditions for tree replacement; any trees which become diseased or die within 5 years of the completion of the development should be replaced in the next planting season by a tree of the same species and of the similar age and size. Planning Application Copies of tree and land surveys should be submitted with the application. The design of the development should acknowledge the zones described above and should include the methods of construction to be used together with how construction procedure will protect the trees on the site. Details of considerations are mentioned below: Page 3 of 5

4 Measures to Protect Trees during Construction 1 The Protected Zone must be considered sacrosanct; there should be no activity within this zone and contractors must be made aware of the requirements of the zone. Fencing should be erected to mark this zone prior to the commencement of work on the site, and retained for the duration of construction work. Fencing of the Protected Zone during construction Fencing should be robust and not easily removable. Robustness is related to local conditions such as aspect and soil conditions which will influence the extent to which a fence will remain upright. Most fences should be a minimum of 1.2 metres tall and should comprise a lattice of vertical and horizontal scaffolding supporting cleft chestnut pale fencing or chain link fencing. If the tree is particularly fragile, a fence of at least 2.4 metres is recommended to support man-made boards of 20mm. The fence must be in place prior to commencement of work and should be clearly signed indicating that it should not be removed. Fencing may only be removed with the consent of the planning authority; fence removal does not signal that construction work is allowed in the protected zone of the tree. If temporary access through the protected zone is absolutely necessary a series of reinforced concrete slabs should be laid to protect the soil from compaction. More substantial boarding may be required to support heavier loads. 2 Compaction of soil must be avoided as this destroys the soil s pore structure which in turn alters the trees ability for water uptake. Compaction can be caused by the storage of materials, machinery and soil and by the use of an area as a thoroughfare by people and vehicles and for temporary constructions such as site huts. 3 Excavation for foundations and utilities must be considered in relation to the welfare of root systems. It is a common misconception that the root system of a tree extends in a narrow, deep band directly below the trunk. In reality the roots extend a large distance laterally at a shallow depth, often at approximately 60cm. Shallow foundations thus impact on the root systems. The closer the excavation is to the tree the greater the chance of damage. Construction, therefore, should not be within the protected zone of the tree. This also benefits the building as roots can damage foundations. Where foundations are to be located near major roots they should carefully bridge them. Construction also has an impact on the hydrological cycle with compaction of soils and the laying of tarmac reducing infiltration rates and increasing runoff. This affects water available for tree growth. 4 Ground level change should acknowledge the location of tree roots. Reduction in ground level causes the severance of roots and an alteration of drainage rates which affect water availability. Increases in Page 4 of 5

5 ground level causes compaction and can suffocate and damage shallow and fragile roots. 5 Impact by machinery can damage trees in an obvious way; torn branches, damaged bark and general trunk wounds allow easier access to disease and parasites which cause decay. 6 Contamination of soil through the leakage of chemicals from construction materials such as concrete, fuel and oil should be avoided through secure storage. Storage of these must not occur in the protected zone and should be down hill from the tree, ideally 10m from the protected zone to allow for leaching of materials through the soil. 7 Intense heat and fire will damage both roots and the bark of the tree. Damage may not be immediately obvious however as this can occur internally. Fires should be kept away from trees; fires should be lit in a position where any flames will not encroach within 5 metres of any part of the tree. 8 Tree Surgery may require consent if the tree is protected or is within a Conservation Area. Any surgery or necessary felling should be detailed in the planning application and should be undertaken prior to commencement of construction; it is easier to carry out surgery without unavoidable construction obstacles. It should also be noted that restrictions on felling and surgery could be implemented during bird nesting season For further information please refer to the British Standards guide, Trees in Relation to Construction, This provides information on the protection of trees during construction and the need to consider their wellbeing in design. There is also a new 2005 version currently available in draft form. If you wish to make any comment, or have any queries, please contact Devon County Council using the details shown below. Development Management Environment, Economy & Culture Directorate Devon County Council ABG Lucombe House County Hall planning@devon.gov.uk Exeter Telephone: EX2 4QW Page 5 of 5