Tree protection plans and the fencing specification

A tree protection plan is the drawing that tells a groundworker where they may not go. It takes the root protection areas from the tree survey, turns them into construction exclusion zones on the site layout, and shows the barrier that will keep plant, materials and vehicles out of them. Under BS 5837:2012 the default barrier is a scaffold framework with welded mesh panels, at least two metres high, braced and fixed so it cannot be pushed over or quietly relocated.

Most councils condition it. The condition typically requires the barrier to be erected in accordance with an approved plan before any development takes place and retained until construction is complete, and it is one of the conditions tree officers actually visit site to check.

What the plan shows

The plan is drawn over the proposed site layout, at a scale where the fence line can be measured, and it carries a defined set of information.

• Every retained tree with its survey reference number and its retention category.
• The root protection area for each, as calculated in the survey.
• The construction exclusion zone and the exact line of the protective barrier, dimensioned from fixed points on site.
• Areas of ground protection where access inside a protection zone is unavoidable, with the build-up referenced to a detail.
• Trees to be removed, clearly distinguished, with the removal sequence if that matters.
• Site facilities: the compound, welfare units, material storage, cement and mortar mixing areas, spoil heaps, parking and the site access route.
• Service routes and the point at which any trench enters a protection zone.

That last group is what separates a plan that works from one that is decorative. If the drawing does not say where the bricks are stacked and where the mixer stands, they will end up under the largest tree, because that is the flattest shaded spot on the site.

The plan is normally issued with the Arboricultural Impact Assessment and the method statement as a set, cross-referenced by tree number.

Barrier specification and where it can vary

The default specification exists to resist the two things that destroy barriers: being knocked by a machine and being moved by someone in a hurry. Scaffold uprights driven into the ground, horizontal bracing, weldmesh panels wired to the frame, standing at least two metres.

Lighter alternatives are permitted where the standard's conditions are met. Proprietary panels on stabilising feet, adequately braced, are common on small residential sites with limited plant. The judgement is about risk, and it belongs to the arboriculturist rather than to the contractor's estimator.

Two details get missed. The barrier needs to be continuous, so where it meets an existing wall or hedge the junction has to be closed. And it needs to be on the correct side of the line, since a fence erected 300 millimetres inside the marked position over a 40 metre run gives away a surprising area.

Where a barrier cannot follow the protection area exactly because of an existing structure, say so on the plan and show the alternative arrangement rather than leaving the contractor to improvise.

Cost is the usual reason a specification gets watered down between approval and installation. It is worth putting the barrier into the demolition or enabling works package rather than the main contract, because the fence has to exist before the first machine arrives and a main contractor appointed later cannot install it in time. And a barrier taken down for a fortnight to allow a crane pad, then reinstated, is a variation the authority should approve in advance rather than discover on a site visit.

Ground protection where exclusion is impossible

Sometimes access inside the zone is unavoidable: a pedestrian route to a rear garden, a scaffold position against an existing wall, a temporary crossing for a mini excavator.

Ground protection replaces exclusion in those areas. The principle is load spreading over the existing grade with no excavation and no change of level: a geotextile separation layer, a granular or cellular load-bearing layer, and a running surface, or scaffold boards on a supporting frame for pedestrian use.

The build-up depends on what will cross it. A route for wheelbarrows is not the same as a route for a tracked machine, and specifying one when the site will use the other is worse than useless because it gives false confidence.

Ground protection is temporary and is removed at completion, so the plan should say who removes it and how the ground is reinstated.

Signage, retention and induction

Barriers should carry all-weather signage at regular intervals stating that the area is a construction exclusion zone and that no access, storage or excavation is permitted. The wording matters less than the frequency, because a sign every 20 metres is read and a single sign at the gate is not.

Retention period comes from the condition. The standard wording keeps the barrier in place until construction is complete, and a request to remove it early for landscaping works needs written agreement.

Site induction is the part nobody draws. Every operative and every subcontractor should be shown the plan and told what the fence means before they start. It costs ten minutes and prevents the phone call about a delivery lorry parked over a protection zone.

Storage, mixing and parking exclusions

Three activities cause most of the damage inside protection zones, and all three are avoidable by allocating space on the drawing.

Material storage compresses soil and, where the material is cement, lime or aggregate, changes the chemistry of the ground beneath it. Mixing washout is worse, because alkaline runoff kills fine roots.

Vehicle parking, including the site manager's van and the operatives' cars, does more cumulative compaction than the heavy plant that visits twice.

Spoil heaps and topsoil storage smother roots and change drainage. Put the stockpile location on the plan and give it a maximum height.

Fuel and chemical storage should be outside every protection zone and bunded, which is an environmental requirement as much as an arboricultural one.

Getting the condition discharged

The discharge application usually needs three things: the approved plan, photographs of the barrier in position taken before work starts, and a statement from the arboriculturist confirming installation matches the specification.

Take the photographs properly. Wide shots showing the full run against a recognisable feature, close shots showing the fixing detail and the signage, and a date on the file. A photograph of one panel proves nothing.

Where supervision is required by the method statement, agree the hold points before work starts and keep the site records, since those records are what the authority asks for if a complaint is made later.

And plan for the aftermath. Once the barrier comes down, the retained trees become part of the finished scheme, so the Landscape Strategy should show the surface treatment, planting and levels within the former exclusion zones, designed so that the ground protected during construction is not compacted during landscaping.

Arboricultural work is specialist and councils usually expect a suitably qualified author, so use an AI-assisted draft for structure and policy framing and have the plan and specification produced by an arboriculturist. You can check which reports a constrained plot needs before briefing one, and Enter your postcode on PlanScope to see whether tree constraints are flagged on your site.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.