Main CAVAT Documents

Case Studies



Oak tree Loughton

Capital Asset Value for Amenity Trees (CAVAT) written by Chris Neilan


CAVAT provides a method for managing trees as public assets rather than liabilities. It is designed not only to be a strategic tool and aid to decision-making in relation to the tree stock as a whole, but also to be applicable to individual cases, where the value of a single tree needs to be expressed in monetary terms.


Therefore there are two versions of the CAVAT method. The Full method is recommended for use in decisions concerning individual trees or groups, when precision is required and sufficient time is available for a full assessment. The Quick method is intended specifically as a strategic tool for management of the stock as a whole, as if it were a financial asset of the com



Here is a brief summary of how the Islington tree officers have been using CAVAT to secure compensation from firms who have damaged their trees, by Jim Chambers, Urban Forest Manager.


“Back in 2007 I was called out to deal with a tree that a skip lorry had destroyed. I managed to gather information on what happened and sent a bill to the skip company.


I charged them for all remedial tree surgery, costs to supply, plant and maintain (for three years) replacement trees, and 20% on top for admin. I explained that if they did not pay this bill, and the matter went to court, I reserved the right to claim the full CAVAT value of the tree which was about £15,000.


Nevertheless, they refused to pay, and there were a few letters back and forth, but I built a strong case by getting witness statements from residents, builders etc.


Eventually the legal department got involved from a non-payment perspective, and at the point where solicitors were being employed for court, the skip firm paid the bill.


Since then we have used the same procedure to claim funds from people who've damaged our trees where we have evidence of them doing so.



To summarise some of our cases from memory -


- We've claimed approx £1,500 from a large supermarket following a delivery van knocking over a tree, similar situations with two other major supermarkets too.  Not to put too finer point on it, but every little helps…


- In numerous cases where van drivers have hit branches and caused damage, we've claimed the costs of remedial works and compensation for the loss in value to the tree involved.


- We claimed over £3000 from a construction firm who illegally sawed off one branch from a street tree adjacent to their development,


- We claimed £1000 from a company that cut down a sapling on the street to allow a long vehicle to access their site.


- We claimed over £9000 from a firm that undertook unauthorised work to a council tree adjacent to the work site, specifically for the loss of CAVAT value.


- We claimed over £7000 from Murphy's after a street tree was knocked down by a lorry.


- We've received over a £1000 from a scaffolding firm who hacked down a tree in a council house garden they were working in.


- We also took a building firm to court for non payment of approx £1000 bill we sent them for hacking off all the overhanging branches over their property, leaving the tree in need of further surgery and in our view dangerous, and we won. The judge agreed that their actions had gone far beyond any common law rights and awarded us victory, the bill has been paid


A couple of years ago LBI improved our Tree Policy;


'Policy 9: The council will seek compensation from any external organisation responsible for significant damage to or removal of any council owned tree(s) to the value as calculated by CAVAT.'



I would be very happy to discuss this further and to advise anyone on how we've dealt with these issues.


As responsible tree owners, we cannot allow people or firms to get away with damaging our trees, and CAVAT is an effective way to hit the culprits where it hurts and reduce the likelihood of them re-offending.


Loughton street trees

Tree Valuation: CAVAT

The benefits of using a tree valuation method.




The site in Hotwells Road is one of the key arterial routes in and out of the city, many  of which are characterised by trees lined avenues or rows of trees.  Bristol Council Tree Officers pro-actively engaged with Wessex Water to amend plans to reduce the level of tree loss.


Following detailed site investigation, works were allowed close to mature planes and within British Standard Protection zones where no roots had been found.  Where roots were found and monetary compensation was gained to allow for replacement planting once works were complete, and to allow for new mitigatory street tree planting elsewhere within the city.



Case Study: Jacobs Well Road and Hotwells Road, Bristol.


Sewerage system improvement works were scheduled to be built within the carriageway around Jacobs Wells Road and along Hotwells Road, Bristol in the Autumn/Winter of 2006.  The works involved open trench excavation to allow the construction of storm water storage units and pipework to deal with storm surge events, to albeit the flooding of surrounding properties.


A number of mature trees within the ownership of Bristol Council were situated adjacent to the scheme, some of which were shown for removal to implement the scheme.  The trees ranged in age from newly planted 30-35cm girth trees to 150 year old plane trees situated within the centre of the existing roundabout.


Bristol Council used the CAVAT system to put a monetary value on two trees shown for removal which came to £60,000 as well as other mature plane trees .  The system was easy to use and the monetary value allowed tree officers to work with other professionals to rationalise the need to retain large trees as part of the scheme.


The significant monetary value of the trees was such that all parties wanted to look at alternative construction methods and design to accommodate tree retention.  In areas where potential conflict existed, significant trenches were opened to investigate where roots from adjoining trees were located and to see whether storage units and pipework could be built whilst retaining the trees.


In one location significant structural roots where found to a depth of 3 metres plus.  In this location the existence of other services meant it was not possible to move pipework, or to redesign storage units (whilst still allowing sufficient storage of storm water run off).  It was also not possible to sever roots without de-stabilising adjoining trees.  Both parties agreed to the removal of two trees, with Wessex Water providing a monetary compensation for loss of amenity to allow for mitigatory planting.


The Hotwells Road site is an excellent example of what can be achieved both in terms of retention of existing trees where practicable, detailed investigation to establish root growth within the built environment, as well as replacement planting and monetary compensation for further tree planting within the city to deal with the issue of loss of amenity.





To give other professional disciplines a better understanding of why tree officers wish to retain large trees         through the use of a monetary valuation system.

To establish were roots from adjoining trees were growing within the highway.

To look at design solutions and the placement of pipework to enable the retention of existing  mature trees.

To accommodate future generations of trees adjacent to the site.

To maintain the green infrastructure associated with this arterial route into the city.

To look at mitigatory planting where appropriate and necessary.




Involvement prior to the construction phase of development.

Robust interpretation of tree retention policies.

Use of CAVAT tree valuation to help engineers understand the importance of mature trees and why the Local Authority wished to see them retained.

Extensive trial pit investigation to establish rooting zone and location of structural roots.

Building footprint agreed prior to major works commencing on site.

Construction phase site supervision inspections by the tree officer and consulting arborist.

The agreement of monetary compensation for mitigatory planting.

The accommodation of planting pits for replacement tree planting adjacent to the new storage units.




Retention of prominent large species adjacent to working areas.

Replacement planting of four semi-mature specimen trees on site.

A financial contribution for tree planting elsewhere in the city to offset the removal of the two mature specimens.

Effective communications, increased knowledge base and trust building between all participants.  This has lead to earlier involvement in subsequent projects at pre-design stage and the retention of other trees within the city through the redesign of schemes.

The use of CAVAT to provide a monetary valuation that other professional disciplines can understand.  This takes us away from historic one large tree out, a few small ones back in which over time erodes tree cover.

Use of CAVAT on subsequent schemes has led to increased retention of large trees especially within the city  centre, following changes to scheme designs, and improved site investigation which show trees can be retained close to new buildings and infrastructure.


Lessons Learned


Engagement on tree issues must be undertaken at the earliest opportunity for example the conceptual and design stages

Expert arboricultural advice should be obtained at these stages of the scheme as well as during development and implementation of any scheme.

It is possible to design solutions that allow retention of large trees

Establish effective communications between partners

Construction phase site supervision inspections by the tree officer are essential

It is important to look at different design solutions but it may not always possible to retain larger trees.  Where this is the case it is important that systems such as CAVAT are used to allow for adequate replacement.




1.  Bristol City Council Arboricultural Team


2.  Wessex Water


3.  CBA Trees.


4.  Hillier Nurseries


For further informatiion:




Loughton street trees



Valuation text in progress





Text goes here







Oak tree Loughton



Forum text in progress





Text goes here