Trees are an important element in the environmental quality and landscape green network of Glasgow.

Trees usefully absorb carbon dioxide, release oxygen and help to clean and filter air of dust and pollutants. They can play an important role in nature and wildlife conservation, as well as reducing wind exposure, screening unsightly views and providing a contrast to the built environment.

Under Section 159 of the Town and Country Planning (Scotland) Act 1997 it is the duty of the planning authority to:

(a) ensure, wherever it is appropriate, that in granting planning permission for any development adequate provision is made, by the imposition of conditions, for the preservation or planting of trees; and

(b) make such (tree preservation) orders under section 160 of the Act as appear to the authority to be necessary in connection with the grant of such permission, whether giving effect to such conditions or otherwise (see policy ENV11: Tree Preservation Orders (TPO)).

The following policy aims to safeguard existing trees, promote new tree planting and encourage the healthy maintenance and management of the City’s tree stock as recommended in the City’s Landscape Strategy. It gives advice on the standards expected from new developments to ensure that existing trees are protected and integrated into new development, that new planting is considered and adequately implemented and that both existing and new trees are adequately maintained.

This policy covers the following topics:

1. REQUIREMENTS FOR PLANNING SUBMISSIONS 

(a) Existing Trees

The following guidance should be taken into account:

(iv) the survey should be carried out by a competent arboriculturalist at an early stage in order that the impact of the development proposals on the trees can be assessed;

(v) there will be a presumption in favour of retaining all healthy and structurally sound trees on development sites, especially those that are protected by designation. The proposed loss of significant trees on a development site may lead to the refusal of permission;

(vi) the design of all development proposals must take adequate account of trees. This will include sufficient spacing between buildings and trees allowing for future growth, adequate protection of trees during site development and prohibition of any site works within the branch spread of any tree or greater specified protection zone deemed to be necessary;

 

(vii) on sites with important tree cover, applicants should consider details in relation to temporary protective fencing, site compound location, temporary service provision and storage of site materials and submit details of these on a drawing as part of the application; and

 

(viii) the removal of any protected tree will only be allowed in exceptional circumstances, such as where the tree is a danger to public safety or is diseased, and on the understanding that appropriate replacement planting takes place. Any existing tree that is removed as part of an agreed development scheme must be replaced with the number, size and species of new trees to be agreed with the Council.

(b) New Tree Planting

The following guidance should be taken into account:

(i) development proposals may be required to provide appropriate high quality tree planting and submit details of such provision as part of a full planning application. A maintenance and management scheme should also be submitted where relevant. Occasionally, this level of detail may be requested for outline applications; and

 

(ii) development proposals are required to promote nature conservation through the use of native species, where appropriate.

2. SITE LAYOUT 

The following guidance should be taken into account:

(a) the root system of most trees tends to be very shallow and radiates out for considerable distances, often outside the crown spread of the tree. Most of the root system is located in the top 600 mm of soil, therefore even shallow excavations can adversely affect the health of the tree and can render it unstable and a future liability. Where changes of ground level occur in the vicinity of areas of trees to be retained, care must be taken to ensure that such changes of level do not result in their subsequent loss, e.g. by altering drainage which would result in either water-logging or drying out. Work will not normally be allowed within the canopy spread of trees but, in exceptional circumstances, where work is unavoidable, excavations must be carried out by hand under the supervision of a competent arboriculturalist with minimal disturbance to the root system;

(b) it is particularly important that reasonable spacing between houses and trees is allowed at the design and planning stage, taking into account the future growth of the tree. This minimises problems of shading and leaf drop and any possibility of root damage to foundations;

(c) significant and protected existing trees and new boundary or barrier tree planting should, where possible, be located within common landscape areas in order to reflect their importance as a public amenity, and to facilitate future management and continuity of care. Areas of tree planting in common ownership must be accessible for maintenance, e.g. not completely fenced in behind gardens; and

(d) the following factors should also be considered:

(i) the basic requirements of trees’ root and feeding system;

 

(ii) the dimensions of the fully grown tree and whether it will shade windows and gardens should be assessed. Careful choice of species and siting will reduce the need for pruning;

(iii) no underground drains, service runs or kerb lines should be placed within the root spread of trees. Applicants may be required to submit information on such works as part of their planning application in order to ensure compliance with this provision;

(iv) ground levels within the root spread of existing trees should not be raised or lowered. These areas should be largely unpaved or with a surface which permits adequate drainage;

(v) care should be taken to ensure that trees do not cause a traffic hazard by obstructing visibility or the passage of high sided vehicles. Trees should not reduce the effectiveness of street lighting due to overhanging branches;

 

(vi) heavy leaf-fall trees such as horse chestnuts should not be used near roads, car parks and paths where slippery conditions could be dangerous. These trees should also be kept clear of gutters and drains;

(vii) trees such as Tilia (lime) and Acers (sycamore) which are affected by sugar secreting aphids should be avoided in car parks or near seating areas; and

 

(viii) Cupressocyparis Leylandii and Chamaecyparis Lawsoniana should not be planted as a boundary hedge within new housing developments.

3. PROTECTION AND MANAGEMENT OF TREES DURING CONSTRUCTION 

The following guidance should be taken into account:

(a) all development proposals must make provision for the proper and beneficial management of trees and woodland areas and must adhere to BS 5837:1991 Trees in Relation to Construction and BS 3998:1989 Recommendations for Tree Work as a minimum requirement. Trees on development sites should be protected at all stages of development;

(b) in order to avoid damage to existing trees BS 5837:1991 Trees in Relation to Construction should be adopted and followed:

(i) before the arrival of any materials, accommodation or machinery and before any demolition or development commences, trees should be fenced around the outermost branch spread with chestnut paling or chain link fencing at least 1.2 m high fixed to stout posts and rails to create a total exclusion zone in compliance with BS 5837:1991. In certain cases, this distance may have to be increased to allow for tree growth during the construction period or where trees are likely to be particularly sensitive to damage;

 

(ii) no storage of materials, lighting of fires, erection of site accommodation, digging of service trenches, depositing of waste due to tipping or leakage, ground compaction by construction traffic or other action likely to affect the health of the trees will be permitted within the protected area;

(iii) the fence will be properly maintained during construction to provide adequate protection;

 

(iv) the site should be inspected frequently during the works to ensure that the trees are not being damaged;

 

(v) site fires should be excluded to a minimum of 20 metres distance from the outermost crown spread of any tree to be retained on the site; and

(vi) where the protected area contains newly planted or young trees, the area should be kept free of weed growth at all times.

BS 5837:1991 Trees in Relation to Construction provides clear guidance on these matters.

(c) a professional programme of tree work for the development site must be agreed with the Council. The Management Plan should include the following:

(i) provision for the removal of dead or dangerous trees and the removal of other trees as specified in the planning permission;

 

(ii) crown lifting, crown thinning or other works required to ensure that retained trees are in a safe and healthy condition on completion of the development;

 

(iii) the carrying out of remedial surgery work after the completion of the development to rectify problems that may have resulted from the site works; and

(iv) provision for the fertilisation and improvement of the soil around the trees and for the aeration of the soil where compaction has occurred.

The above works should be in accordance with BS 3998:1989 Recommendations for Tree Work and the Forestry and Arboricultural Safety Council (FASTCo) Guides applicable at the time. The tree works should be agreed with the Council and carried out by a competent arboriculturalist. On large jobs and those covered by protected trees, all scheduled operations agreed with the Council should be contained within a Method Statement which clearly indicates the phases and timing of tree work operations. Particular attention should be paid to the provision of existing and new services by the public utilities. Work to existing services which takes place within the vicinity of trees should conform to the National Joint Utilities Group (NJUG) Guidelines for the Planning, Installation and Maintenance of Utility Services in Proximity to Trees April 1995.

(d) developers will be required to ensure the establishment of the planting by adequate maintenance and the replacement of all dead, dying, diseased or removed stock for a period of five years from the completion of the development.

4. NEW TREE PLANTING 

(a) the success of new tree planting is dependent on the choice of the correct species in suitable locations. Trees also require sufficient oxygen, nutrients and water. Good ground conditions and ground preparation are crucial and there must be no soil compaction or water-logging. Ground contamination may adversely affect tree growth and must be addressed. In some cases a soil survey may be requested to establish the conditions for new planting. Prior to planting, locally occurring phytotoxic material or pollutants, e.g. oil or diesel fuel, must be dug out and replaced by suitable soil.

(b) provision should be made for the planting and successful growth of new trees, especially in residential, commercial, industrial and retail-park developments. Residential provision should be generally on the basis of at least two trees per dwelling. Where parking forms part of a development, one new tree per car parking space should be allocated. The size of trees to be planted will vary according to the situation.

(c) where trees are to be planted in pits, the pits should be properly prepared and the trees correctly staked and tied, kept free of weeds and, during establishment, well watered in periods of dry weather. In restricted areas of hard surface the use of proprietary tree soils with load bearing properties is recommended.

(d) for larger areas of structure planting, ground preparation by ploughing and the use of small stock is recommended. 10-15% of feathered stock may be added for immediate effect.

(e) landscape proposals and site layouts for woodland, structure and screening planting should include native species, both conifer and broadleaf.

(f) new trees should conform to and be planted in accordance with the following:

All replacement stock should be planted and maintained as detailed in BS 4428:1989 (Section 7): Recommendations for General Landscape Operations.

See 2. Site Layout for more detailed guidance on new tree planting.

5. PLANNING CONDITIONS 

Conditions may be applied to cover a wide range of tree issues including protection of existing trees during construction, details of new tree planting, ground preparation, soil quality and future maintenance and management proposals.

Under certain circumstances, the Planning Authority may regard existing or proposed trees to be of sufficient significance that a Section 75 Agreement is entered into with the owner in order to secure future management. The planning authority may also decide that a TPO be served on existing or new tree planting.

Failure to comply with the terms of the agreed management programme and the conditions of the planning permission, or damage to trees intended to be retained, will result in enforcement proceedings or other appropriate action.

6. FURTHER ADVICE 

Detailed technical advice on the care and protection of trees should be sought from an appropriate expert. The Arboricultural Association has a list of approved consultants and contractors which is available from Ampfield House, Ampfield, Near Romsey, Hampshire, S05 9PA. Telephone: 01794 368717.

To discuss proposals before making a formal planning application, or on the need for consent for tree work, contact Development and Regeneration Services, Landscape and Environment (Address: 229 George Street, Glasgow G1 1QU. Telephone: 0141 287 7209).

See also Policy ENV 11: Tree Preservation Orders (TPOs).