Trees in Relation to Planning Applications and Development

Arboricultural Impact Assessment

An Arboricultural Impact Assessment is also known as:  Arboricultural Implications Survey, Arboricultural Implication Assessment, Arboricultural Impact Appraisal, Pre-Development Tree Assessment. The assessment must be carried out in accordance with the current British Standard 5837.

An Arboricultural Impact Assessment (AIA)  is a type of tree survey that considers how a proposed development and its associated trees will co-exist and interact in the present and future.  Ribble Valley Borough Council requests an AIA whenever trees are potentially affected by a proposed development in order to satisfy ourselves that factors such as root protection, changes in levels, installation of services, material storage, and so on have been given due consideration during the initial design process and that these items will not prove detrimental to important trees. The Council also need to ensure that future issues, such as the long term effects of changing a surface level or the future need to prune or remove trees because they cast excessive shade or encroach upon property, are addressed and avoided.

The carrying out of an AIA is recommended as one of the first steps in the planning process. This can then inform the design and layout of the development which in turn will avoid conflict between the trees and the requirements of the development.  This process will then save the planners time and money because major site layout modifications are kept to a minimum.  The AIA also allows ancient and veteran trees and woodlands, important hedgerows, and other significant habitat to be identified at an early stage allowing for improvements to those habitats to be included within the initial application.

Items to consider during an AIA:

  • Tree root protection zones (these should be clearly marked on a scale plan)
  • Likely alteration to site levels
  • Likely changes to surfacing
  • Likely locations for the layout of services
  • Demolition of existing buildings and removal of hardstanding
  • Exposure due to tree and structure removal
  • Sunlight and shading
  • Likely site access and layout during construction
  • Allocation of a suitable area for plant and material storage
  • Fruit production (fouling footpaths)
  • Initial suggestions for additional/replacement tree planting
  • Birds, bats and other fauna (are further ecology/specialist surveys likely to be required?)

An AIA should include a full tree schedule and a tree constraints plan (to scale). If an indicative layout has been drafted this should be included with the AIA along with all other relevant information.

The AIA allows all potential conflicts to be identified at an early stage, this allows these conflicts to be resolved as a part of the planning process before a decision is made - reducing the need for a lengthy list of planning conditions.