Tree bonds: securing protection through a planning obligation
A tree bond is money secured by a section 106 obligation and forfeited if protected trees are damaged. Here is how the sum is set, how release works, and where a bond fails the statutory tests.
A tree bond is a sum of money, secured through a planning obligation, that a developer forfeits if protected trees are damaged or lost during construction. Authorities ask for them because a planning condition cannot require payment of money, and because the remedies available after a tree has been destroyed are slow, uncertain and rarely restore anything of equivalent value.
They are not universal. Most schemes with trees on them proceed on conditions alone. Bonds appear where the arboricultural stakes are high: a category A oak inside a construction zone, a boundary of mature limes in a conservation area, or an applicant with a history the authority remembers.
Why authorities ask for one
Enforcement after the event is weak. Where a tree protected by a Tree Preservation Order is removed in contravention of the Order, the landowner is under a duty to replace it, and the authority can serve a replacement notice. A whip planted in place of a 150-year-old beech satisfies the law and replaces almost nothing.
Prosecution is available for the most serious breaches, but it takes time, needs evidence and delivers a fine rather than a tree. A bond changes the incentive before the damage, which is the only point at which the outcome can still be different.
The other driver is establishment. Replacement planting secured by condition fails quietly: nobody waters it in the second summer, half of it dies, and by the time anyone notices, the condition has been signed off. A bond with a release tied to survival at the end of an establishment period keeps someone interested.
What a bond can and cannot secure
It can secure a payment on the occurrence of defined events: damage to a retained tree beyond an agreed threshold, removal of a retained tree without consent, failure to implement the approved protection measures, or failure of replacement planting to survive an agreed period.
It cannot make an unacceptable scheme acceptable by buying off harm. An obligation must meet the statutory tests in regulation 122 of the Community Infrastructure Levy Regulations 2010: necessary to make the development acceptable in planning terms, directly related to the development, and fairly and reasonably related in scale and kind. A bond that is in truth a payment for the right to remove a tree fails the first test.
It also cannot duplicate what a condition already does. Where the protection measures themselves are secured by condition, with the tree survey and protection plan approved and an arboricultural method statement in place, the obligation should cover only the financial consequence of breach.
Calculating the sum
There is no statutory formula, and this is where negotiations stall. Three approaches are in general use.
The first is replacement cost: the price of supplying, planting, staking, irrigating and maintaining semi-mature stock of a size that gives some visual replacement, plus a contingency. It produces defensible numbers and tends to be lower than the alternatives.
The second is an amenity valuation. CAVAT, the capital asset valuation for amenity trees, and the Helliwell system both produce a value for a tree as an amenity asset rather than as a horticultural item. Authorities that have adopted one of these in a supplementary planning document will apply it, and the figures for large mature trees can be substantial.
The third is a simple multiple of the landscape contract value, often applied where the concern is establishment rather than loss of an existing specimen.
Whichever applies, three drafting points matter: whether the sum is indexed, whether it is per tree or a single pot, and whether partial damage triggers a partial call. A single undifferentiated sum for a group of fifteen trees produces an argument the first time a branch is torn off.
Release conditions and timing
Staged release is normal and sensible. A typical structure releases part of the bond on certified completion of the construction phase, with the arboricultural clerk of works confirming that the protection measures were maintained, and the balance at the end of an establishment period, commonly five years, subject to survival criteria.
The certification question is the one to settle early. Who signs off, on what evidence, and what happens if they refuse. A bond with no defined certifier is a bond that never gets released, and developers who have been through that once insist on naming the mechanism.
Survival criteria belong in the agreement rather than in correspondence. Define the percentage of planting that must be alive and in good health, define what happens to failures, and tie the definitions to the same specification used in the Landscape Strategy and in any planting conditions covering species, stock size and establishment.
Alternatives to a cash bond
Cash tied up for five years is expensive. The alternatives, in rough order of how often authorities accept them:
- A bank guarantee or surety bond from an approved provider, which costs a premium but frees the capital
- A parent company guarantee, where the parent has the covenant strength to make it meaningful
- A retention within an existing section 106 payment schedule
- An escrow arrangement with a solicitor holding the sum
- A staged planting obligation, where later phases cannot start until earlier planting is certified
The last of those is underused. Linking a commercial trigger, such as occupation of a later phase, to arboricultural performance achieves the same result as a bond without the cash cost, and some authorities prefer it because it is easier to enforce.
The tests an obligation must meet
Section 106 of the Town and Country Planning Act 1990 allows an obligation to restrict development, require operations to be carried out, require land to be used in a specified way, or require sums to be paid. A bond sits in the last category, usually structured as a payment triggered by a defined event.
Beyond regulation 122, keep two practical tests in mind. Is the obligation enforceable against a successor in title, which matters if the site is sold mid-build. And is it proportionate to the scheme, because an obligation that costs more to administer than the trees are worth invites a challenge at appeal.
Where an authority proposes a bond on a small scheme with two category C trees, the proportionality argument is usually winnable. Where the trees are category A and irreplaceable in any meaningful timeframe, it usually is not.
Negotiating the drafting
Settle these before engrossment:
- The trigger events, defined by reference to the approved protection plan rather than to general concepts of damage.
- The quantum, the basis of calculation and whether it is indexed.
- The release mechanism, the certifier and the timescale for certification.
- What happens on partial damage, including whether an arboricultural assessment determines the reduction in value.
- Dispute resolution, ideally expert determination by an arboriculturist rather than litigation.
- The interaction with conditions, so the same failure cannot be penalised twice.
Get the arboriculturist who wrote the impact assessment to read the draft clauses. They will spot the mismatch between the protection plan and the obligation wording that a solicitor cannot, and that mismatch is what causes trouble two years later when a service trench appears inside a root protection area. The practical steps for discharging a tree protection condition without delay apply to the bond paperwork as well.
This is general guidance rather than legal advice, and the drafting of a planning obligation affects property rights, so take advice from a solicitor and an arboriculturist before signature.
PlanScope drafts the arboricultural and landscape documents that sit behind these negotiations, structured to UK planning policy, with survey data flagged rather than assumed. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Why can't a planning condition require a tree bond?
Conditions cannot lawfully require the payment of money, so any financial guarantee has to sit in a planning obligation under section 106 of the Town and Country Planning Act 1990. The protection measures themselves are normally secured by condition, with the obligation dealing only with the financial consequence of a breach.
How is the bond sum calculated?
There is no statutory formula. Authorities use replacement cost, an amenity valuation system such as CAVAT or Helliwell where they have adopted one in policy, or a multiple of the landscape contract value. Whichever applies, agree whether the sum is indexed, whether it is per tree or a single pot, and how partial damage is treated.
When is a tree bond released?
Usually in stages: part on certified completion of construction, with an arboricultural clerk of works confirming protection measures were maintained, and the balance at the end of an establishment period, commonly five years, subject to survival criteria. Name the certifier and the evidence required in the agreement itself.
Can I offer something instead of cash?
Often, yes. Bank guarantees, surety bonds, parent company guarantees, escrow arrangements and retentions within an existing payment schedule are all used. So is a staged obligation linking occupation of a later phase to certified planting in an earlier one, which some authorities prefer because it is easier to enforce.
Can a bond be challenged as unreasonable?
Yes. An obligation must be necessary to make the development acceptable, directly related to it and fairly and reasonably related in scale and kind, under regulation 122 of the Community Infrastructure Levy Regulations 2010. A disproportionate bond on a small scheme with low value trees is a familiar argument at appeal.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.