Arboricultural Impact Assessment

We Provide Expert Arboricultural Impact Assessments

An Arboricultural Impact Assessment is a technical report often requested by town planners to assess the potential impact of a proposed building project on adjacent trees. Godwins Tree Surveys provide professional Arboricultural Impact Assessments to aid the validation of your planning application.

What Is an Arboricultural Impact Assessment?

In the early stages of any building project, the parties involved must consider the potential impact of their proposals on the environment. And crucially, one of the most important – but often overlooked – impacts of many jobs come at the expense of the project’s adjacent trees, risking the integrity of the area’s natural environment in the process. An Arboricultural Impact Assessment is designed to minimise these risks, as town planners assess the potential impact of the proposed development on trees within the site. Off the back of this, a comprehensive Tree Protection Plan is produced to ensure the safety of the area’s trees before, during, and after any construction activity takes place.

The point of an Arboricultural Impact Assessment is to identify and mitigate any problems that might arise before they become costly and potentially dangerous. Before a planning application is submitted, an arboriculturalist will identify valuable trees in close proximity to the construction project and then balance those against the potentially damaging construction activities that will take place. These activities include excavations within the tree’s rooting area, sustained damage from heavy construction vehicles, and the positioning of buildings too close to a tree’s branches or roots – and all of these issues, among many others, will be identified and addressed within the Arboricultural Impact Assessment.

In order to ensure the safety and health of trees during – and after – the construction phase of a development, the Arboricultural Impact Assessment details which specific tree protection measures are required for each job. From tree protection fencing, to construction exclusion zones and the introduction of construction techniques that are sympathetic to tree roots. There are a multitude of measures to choose from – the job of the Arboricultural Impact Assessment is to identify the best ones for your job, and put them into place swiftly and effectively.

Why Is It Important to Protect Trees on a Development Site?

It’s sometimes easy to overlook, but trees bring so many benefits. Whether they’re environmental, economic, or social benefits – healthy, well-structured trees really do add to the character of an area, not to mention its actual financial value. That’s why retaining good quality trees, and mitigating tree loss, in order to reduce the potential negative impacts of construction, is crucial.

Sometimes, trees within a development site may be protected by statutory laws like a Tree Preservation Order. In times like this, where a tree growing on adjacent land to your project might have roots that grow within your development area, an Arboricultural Impact Assessment can be invaluable in ensuring your proposed work surrounding those trees remains within the law – saving you time and money in the long run.


What Are the Dangers Faced by Trees on Construction Sites?

Above ground, the risks to trees on your site are obvious. Trunk wounds and broken branches are obvious to see – but the less obvious, and potentially more damaging impacts can be found below ground. As part of any Arboricultural Impact Assessment and Tree Protection Plan, the Root Protection Area of any potentially affected trees have to be calculated. This will ensure that the rooting system of the trees doesn’t sustain serious disturbance and damage which could lead to their decline and – in extreme cases – their death. Tree protection fencing plays a key role in this part of the process, preventing heavy vehicles from damaging a tree’s surroundings – and defining safe storage areas and areas where construction isn’t permitted – in a cost-effective and safe way.

Does My Planning Application Need an Arboricultural Impact Assessment?

Projects of any size may require an Arboricultural Impact Assessment, and it’s down to the local planning authority to make that decision. Typically, larger developments such as mass housing and infrastructure will almost always have to have an Arboricultural Impact Assessment, but many smaller projects like private extensions and new driveways may also need one. Of course, every project is unique – but if your site is located within a Conservation Area or you have trees that are protected by Tree Preservation Orders, an Arboricultural Impact Assessment should be your first port of call. 

How Is an Arboricultural Impact Assessment Produced?

The requirements of an Arboricultural Impact Assessment are set out in British Standard BS 5837: Trees in relation to design, demolition and construction, and they are as follows:

Firstly, an arboricultural survey is undertaken to record the species, dimensions and quality of the trees within your site.  It’s also recommended that a topographical survey is carried out prior to this to ensure your development space is used to its full potential.

Next in the Arboricultural Impact Assessment process, a Tree Constraints Plan is produced. This is necessary to identify the desired tree retention category of your trees – either A, B, C or U – and then identify their Root Protection Area. The Tree Constraints Plan should ideally be used to design the proposed layout of your project, and at this point, a decision needs to be made about potential tree removals and retentions. This decision takes into account the quality of your trees and also assesses the practicalities of retaining them whilst achieving your development’s maximum potential.

The bigger picture begins to come together in the next step, where your proposed development layout is placed on top of your Tree Constraints Plan. At this point of the process, potential areas of conflict between the retained trees and construction activity can be identified and mitigated – and we’ll hold discussions with you and your project architect about the best course of action before finalising our report.

Once the development layout has been finalised, and those trees identified for removal have been agreed, tree protection measures such as temporary tree protection fencing barriers and ground protection to prevent soil compaction are identified and detailed on the Tree Protection Plan. The Tree Protection Plan will also highlight which trees are to be removed and identify those trees that require remedial works. Finally, the Arboricultural Impact Assessment will suggest mitigation measures such as new trees to replace any recommended for removal.

In addition to an Arboricultural Impact Assessment, as part of planning approval, the local planning authority may occasionally stipulate that an Arboricultural Method Statement is required to satisfy reserved matters or planning conditions. This generally applies where construction activity falls within the tree rooting area or pruning works are required.