Arboricultural Impact Assessments

Within the planning process, an understanding is needed of how any proposed development or construction will impact the trees on site. This requires a particular type of tree survey known as an Arboricultural Impact Assessment (AIA), and is needed with the submission of a full planning application.

Tree removal is one of the most significant and recognisable impacts a development can have. However, there are many more ways in which construction can impact trees without being removed. For example, movement of construction machinery across root areas, excavation within the root area and the construction of hard surfaces can all affect a tree if it is not adequately protected.

Tree Assessment Plans

As part of the Arboricultural Impact Assessment, a Tree Assessment Plan (TAP) is produced using the Tree Constraints Plan (TCP) and the design proposals. This Tree Assessment Plan highlights where the impacts are and outlines potential mitigation and tree protection measures that will be needed to protect the trees being retained.

The Arboricultural Impact Assessment (AIA)

The Assessment identifies all possible impacts of a proposed development design to the trees on a site and identifies which trees will require removal and those which can be retained with protection measures applied.

For retained trees, the Arboricultural Impact Assessment (AIA) identifies the effect of the proposed development on the impacts below ground (the roots), as well as the impacts above ground (the crown).

Arboricultural Impact Assessments also identify the impact the trees themselves will have on a future development, such as from shading and production of leaf litter. This allows designs to consider the positioning of any building or extension and avoid pressure for tree removal or pruning at a later stage.

Further guidance on ancient woodland and veteran trees:

Browse Tree Surveys

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The BS5837:2012 Arboricultural Survey aims to identify trees which are protected by law and provides a method of categorising any trees of great significance at an early stage in a project.

Tree Preservation Orders (TPO)

Some trees are protected by a TPO, enforced by the local planning authority (LPA). It is illegal to carry out any kind of work to these trees without first seeking approval from the LPA with a formal application.

Conservation Areas

Trees within Conservation Areas are afforded a similar level of protection to those covered by a TPO. An application should be made to the LPA before carrying out any kind of work to these trees.

Ancient Woodlands

Ancient Woodland sites are those that have been covered by trees since at least 1600 and have therefore become host to a range of species, creating an irreplaceable habitat.

Some species of tree contribute to the classification and identification of Ancient Woodland. They are also responsible for defining whether a hedgerow is classified as ‘important’ under the Hedgerow Regulations. Even though they may lack considerable vertical height, they still contribute to the total number of woody species within the hedgerow.

Veteran & Ancient Trees

Ancient trees, often associated with an exceptionally large stem diameter for the species, are those showing signs that they are truly old. These trees not only provide visual and cultural importance in the landscape but also host a range of species that younger trees do not.

Veteran trees are those that may not yet be old enough to be considered ancient, but exhibit some similar physical attributes, which are valuable to the ecology of the site.