Trees & Planning
In recognition of the many benefits that trees provide to the environment and the community, they are considered to be a ‘material consideration’ in the planning process. This means that in any planning application put before the local planning authority (LPA), whether it’s for a new conservatory or for a development of 60 new houses, the LPA is required to take into account the possible impact of that development on nearby trees. This applies to all trees, whether or not they have statutory protection as a result of by being within a Conservation Area or being subject to a Tree Preservation Order (TPO).
All about Tree Preservation Orders
Trees in Conservation Areas
Felling Licences
High Hedges & other legislation
Herefordshire Council Administrative Map
Click on the image to the right to be taken to the Council's map showing all Conservation Areas and Tree Preservation Orders
Tree Assessments for Planning Applications
In order that the LPA can make an assessment of any possible impacts on trees and determine if they might be of sufficient consequence to constrain the development, the applicant is required to provide full details of all the trees present within the area for which planning approval is being sought. The amount and type of information you need to provide for the LPA to properly assess a development’s impact on trees will depend on the project, but would normally take the form of a tree report as set out in the British Standard BS 5837:2012, Trees in relation to design, demolition, and construction – Recommendations.
[Note that BS5837 is currently under review and that a revised edition is likely to be published in 2025 and is likely to include several new features. However the current (2012) edition is available HERE ]
In order to avoid delays that could lead to unnecessary costs it’s vital that trees are considered at an early stage: it’s in no-one’s interest if time and money is spent in preparing a proposal which falls at the first hurdle because of a failure to take trees fully into account. The tree survey should therefore be completed and made available to designers before any specific proposals are developed.
Tree Surveys
In the first instance, it will be necessary to have the locations of all trees on the site accurately plotted so that their relationship with proposed new features can be understood. This best achieved by commissioning a measured topographical survey of the site which should accurately show the positions of all trees within the site that have an estimated stem diameter of 75mm or more. (Diameters are based on girths measured at 1.5m above ground level. Be aware, however, that this may be changed to 1.3m when the revised BS5837 is released.)
Trees beyond the site boundary should also be plotted. This applies to those that are growing within a distance of about 12 times their trunk diameters. Trees that directly overhang the site must also be included.
Using the topographical drawing a Tree Survey can be prepared. For all but the very simplest of cases it will generally be advisable to get a qualified arboriculturist to carry out the tree assessment and to prepare a tree survey and report. This will identify the species of each tree and give its measurements (height, trunk diameter and crown spread at the four cardinal points). It will also provide an assessment of its health and structural condition along with an estimate of its likely safe, useful life-expectancy. Based on these factors each tree is allocated to a 'Quality Category', as described below:
Quality Categories:
Category A are trees of Good quality and high value and every effort should be made to ensure they are retained without being harmed.
Category B trees are of Moderate quality and value, being essentially sound and healthy and with a life expectancy of at least 20 years but with characteristics or features that make them unsuitable for inclusion in Category A. The assumption is nonetheless that they would be retained, although in some cases it may be considered that the development under consideration might take precedence.
Category C are defined as being of Low quality, being unremarkable and not of sufficient value as to be regarded as a significant constraint to a development. They are nonetheless capable of being retained and should be retained wherever it may be appropriate. However, their loss would not be unduly deleterious.
Category U includes trees of poor condition, with irremediable defects or otherwise negligible. It includes dead trees and those with short life expectancies (less than 10 years). They cannot be regarded as significant constraints to development although they may nonetheless be of value for conservation reasons.
Veteran and Ancient Woodland should be identified. (Note that one of the proposals put forward for the new revision of BS5837 is that they will be allocated to a new Category V.)
Root Protection Areas (RPAs)
The other critical element in a pre-development tree survey is the calculation of a Root Protection Area (RPA) for each tree. This is defined as ‘A layout tool indicating the minimum area around a tree deemed to contain sufficient rooting volume to maintain the tree’s vitality and where the protection of the roots and soil structure is treated as a priority’
The size of an RPA is calculated as the area of a circle of radius 12 times the diameter of the tree. Thus a tree with a diameter of 30cm would have an RPA of 41 sq.m, which is the area of a circle of radius 3.6m. For large trees, those with a diameter of 1.25m or more, the RPA is capped at 707 sq.m, equivalent to a radius of 15m. (There are formulae for calculating the RPAs of trees with multiple stems.)
Veteran and Ancient trees are treated differently in recognition of their cultural, historical and nature conservation value; their RPAs are based on a circle of 15 times the stem diameter with no upper cap or 5 metres beyond the crown spread, whichever is the greater. For Ancient Woodlands..........
Although RPAs are frequently shown on plans as a circle centred around each tree, it is the area that is more important than the shape, which can be modified. However, any such alteration of the shape of a tree’s RPA ‘should reflect a soundly based arboricultural assessment of likely root distribution’.[BS5837:2012]
Tree Survey Drawings:
The findings of the tree survey will generally be presented as a table and also in the form of an ‘Arboricultural Constraints Plan’. This will show the site in its pre-development form with the locations of the trees plotted with an indication of their categories and with their RPAs clearly shown. The information provided should then be used to inform the design and layout of the proposed development.
When a layout has been developed an Arboricultural Impact Plan can be prepared, in which the layout design is overlayed onto the Constraints Plan. This will enable one to identfy any areas of potential conflict between trees and their RPAs and the proposed structures. Where possible, adjustments to the layout may be made to minimise conflicts. However, where it becomes apparent that the design will require the removal or pruning of certain trees, these will be indicated on the Impact Plan. A Tree Protection Plan may also be required in which Construction Exclusion Zones (CEZs) are designated. These are areas that should be enclosed by suitable Tree Protection Barriers, which should be kept in situ throughout the period of construction to ensure that the rooting areas of the trees are undisturbed by any of the processes involved, not only the construction of new buildings but also any initial site, excavations for underground services, the installation of new hard surfaces and the storage of building materials and spoil.
On submission to the LPA, this documentation will be taken into account in determining the result of the planning application. If approved, the LPA may impose conditions including for the provision of new planting to replace trees that have to be removed or to provide new landscaping. These may (and indeed should) include details of sizes for the new planting stock and impose requirements for their aftercare to ensure they establish successfully.