Trees which are worthy of retention on a site may well pose the largest constraint on the size and design of the new development. It is therefore essential to have a clear understanding of what can and cannot be achieved given the presence of trees at the outset.
Planning policy guidance, as set out by central government, recognises the ever increasing demand for new housing. There is a requirement for higher densities of housing than in the past on development sites, while at the same time providing adequate green space, and sustainability through the protection of the environment, which includes the protection of trees. This apparent contradiction places a strong requirement on the arboriculturalist to assist the planners in deciding which trees can be removed, and which trees should be retained. Having made this crucial decision, the arboriculturalist is to provide detailed specifications for how the trees are to be protected, and ideally, provide on site supervision of the works.
Many planning applications are refused on the grounds that insufficient consideration has been given to the trees. Frequently the lay-out must be re-designed and a new application submitted and this will cost time and money.
We are able to provide the following services for trees on development sites:
- Tree survey:
A tree survey should be carried out in accordance with British Standard 5837 ‘Trees in relation to construction – Recommendations' 2005 (BS5837) before any layout has been designed. This survey will identify the importance and value of each tree or group of trees, taking account of their dimensions, physiological condition, and estimated remaining contribution in years. Each tree will be allocated a category based on their quality and value. In order to undertake the survey, a topographic survey of the site showing the position of each tree is required. A number will be allocated to each tree, and using CAD software, the topographic survey will be amended to create a Tree Survey Plan in which the true crown spread (NESW) is indicated, and the tree category shown by colour. The Tree Survey Report will include a schedule containing all tree data collected on site, and the Tree Survey Plan.
- Assistance with layout design:
From the initial tree survey, a preliminary Tree Constraints Plan should be prepared on which the principal tree constraints are shown. This includes trees which should be shown for retention, the Root Protection Area (RPA) required for each retention tree (an area in m 2 calculated from stem diameter), and the above ground constraints which are the effects of shading created by each tree, and future growth requirements. When trees are located on sites where development is planned it is essential that an arboriculturalist is instructed to assist with the layout design.
- Arboricultural Implication Assessment (AIA):
This is a document which is frequently required by Local Planning Authorities to be submitted as part of the planning application. It provides detailed consideration of the effects that the proposed development will have to the trees, and visa versa. Consideration will be given both to the development process, and the end use of the space. The document provides justification for tree retention and tree losses, and discusses the impact of the development on the trees, and the constraints posed by the trees on the development. Where tree losses are required in order to facilitate the development, it considers re-planting in order to mitigate the loss.
- Arboricultural Method Statement (AMS):
This document provides detailed protection measures required in order to minimise damage to trees to an acceptable level during the development process. The document will include a Tree Protection Plan showing the position of protective barriers and other protection measures such as ground protection. The document will give the sequential order of events required on the site to protect the trees. It will provide detailed specification for measures required to protect the trees, giving consideration to all aspects of the development, including: access; parking; position of services; site hut location; storage of materials etc. The AMS is often required by Local Planning Authorities before full planning permission is granted.
- On-site supervision and monitoring:
This is an essential aspect of development when trees are in close proximity, particularly on sites of complexity. The purpose is to ensure that details specified in the AMS are adhered to, and to provide arboricultural assistance when issues relating to trees arise during the development process. This is increasingly conditioned by Local Planning Authorities.
