Valuation of Amenity Trees

[daltontrees]

As suggested recently elsewhere on Arbtalk by kevnjohnsonmbe, there seems to be interest in a debate about what amenity value really means. So this thread is open for any contributions to the debate. Or anything that anyone wants to put in here like links so that it can serve as a mini resource. The subject has barely been touched upon ever in Arbtalk yet personally I see it lurking in the background of many discussions unable to come forward and speak because it doesn't have the right words to use.

 

I will open it with a few suggestions. First of all, I don't mean wood value or valuation of forestry stock (although there are grey areas in this regard, perhaps that's why 'amenity tree' needs to be defined or we need to talk about the 'amenity' provided by trees whether they are forestry or arboricultural trees).

Secondly, opinions will differ about amenity and how it is affected by good or bad management, and unless the debate can gravitate towards objective (or minimally subjective) measures that take the observer's personal views out of the value, then it will all be a big fat waste of time.

Thirdly, and in the same vein, I am most interested in a numeric outcome (say ££s) that can be weighed up against tree work costs and property values.

Finally, starting off with the intention of keeping it simple seems highly desireable, the simpler it is the more people will use it, but I have spent a lot of time thinking about it and I know it is not simple and never can be. It's like saying accountancy is simple or tree surgery is simple. If contributors all approach the debate not to pick obvious holes in ideas but to try and fix holes by simplifying wherever possible, some consensus might emerge.

[daltontrees]

Here's a simple example of the issues.

A midsize tree growing in a front garden, much loved by the owner, is found to have a fungal infection that will cause it to fall over within 10 years. Without this infection, the Helliwell system values it at £10,000 but due to the infection its value is reduced to £2,500. It will cost £1,000 to remove and grind out and a young replacement will cost £500 to plant, stake, mulch and maintain for 2 years. The risk associated with failure is currrently 'tolerable' (1:20,000) because although failure is likely the chance of it hitting anyone or anything is relatively low. However, the insurers will not cover the owners if someone or something is hit.

Crown reduction is suggested, but although this will reduce windsail and will temporarily make the tree safer this will reduce the tree's chances of resisting the fungal infection and will cost £250.

What does the owner do and why?

[Andy Clark]

Here's a simple example of the issues.

 

A midsize tree growing in a front garden, much loved by the owner, is found to have a fungal infection that will cause it to fall over within 10 years. Without this infection, the Helliwell system values it at £10,000 but due to the infection its value is reduced to £2,500. It will cost £1,000 to remove and grind out and a young replacement will cost £500 to plant, stake, mulch and maintain for 2 years. The risk associated with failure is currrently 'tolerable' (1:20,000) because although failure is likely the chance of it hitting anyone or anything is relatively low. However, the insurers will not cover the owners if someone or something is hit.

 

Crown reduction is suggested, but although this will reduce windsail and will temporarily make the tree safer this will reduce the tree's chances of resisting the fungal infection and will cost £250.

 

What does the owner do and why?

 

 

A bit of an enigmatic question really, because you open with a hypothetical position - in so far that in it's healthy state, the tree would be "worth" £10k. But the tree isn't in a healthy state, so the hypothetical value is therefore irrelevant.

 

In real terms, I would say that it comes down to a judgement call for the tree owner, taking into account their own unquantifiable "love" of the tree - vs quantifiable costs.

 

In terms of costs alone, for example, the owner of the tree may be of limited means and lacking in ready cash, in which case the £250 for reduction may be the only available avenue - alternatively, if cash is no object, then the £1500 to fell and replant is the better option, knowing that the replacement tree has the possibility of reaching a reasonable value in years to come; in which case the £1500 would be a reasonably justifiable investment.

 

Other avenues that could be offset as an investment against the value, could be to explore the possibility of "curing" the tree of it's ailments - depending on the fungal infection - with stem injection and other such treatments. But routes like that are one's that would favour the "love" factor of that particular tree, as opposed to the costs factor.

 

It's almost a question of "how long is a piece of string" to be fair.

 

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[Andy Clark]

As suggested recently elsewhere on Arbtalk by kevnjohnsonmbe, there seems to be interest in a debate about what amenity value really means. So this thread is open for any contributions to the debate. Or anything that anyone wants to put in here like links so that it can serve as a mini resource. The subject has barely been touched upon ever in Arbtalk yet personally I see it lurking in the background of many discussions unable to come forward and speak because it doesn't have the right words to use.

 

I will open it with a few suggestions. First of all, I don't mean wood value or valuation of forestry stock (although there are grey areas in this regard, perhaps that's why 'amenity tree' needs to be defined or we need to talk about the 'amenity' provided by trees whether they are forestry or arboricultural trees).

Secondly, opinions will differ about amenity and how it is affected by good or bad management, and unless the debate can gravitate towards objective (or minimally subjective) measures that take the observer's personal views out of the value, then it will all be a big fat waste of time.

Thirdly, and in the same vein, I am most interested in a numeric outcome (say ££s) that can be weighed up against tree work costs and property values.

Finally, starting off with the intention of keeping it simple seems highly desireable, the simpler it is the more people will use it, but I have spent a lot of time thinking about it and I know it is not simple and never can be. It's like saying accountancy is simple or tree surgery is simple. If contributors all approach the debate not to pick obvious holes in ideas but to try and fix holes by simplifying wherever possible, some consensus might emerge.

 

 

The whole subject of valuation is as long and broad as the debate that revolves around it - primarily because of the many ways in which valuation can be/is applied, and also the now several systems that are in place that can be used to apportion a value.

 

Ok, you've quoted the Helliwell system in your example, but of course we also have the CTLA system - favoured by the ISA; CAVAT - increasingly used to apportion a monetary value of an LA owned trees in conjunction with tree related subsidence insurance claims; and I-TREE - used to apportion a monetary value of the tree in conjunction with it usefulness at carbon offsetting etc.

 

Used out of context, then these systems will invariably give a multitude of different values for a given model tree, so the most important factor, IMO, is that one of context.

 

Right tool for the right job.

 

 

 

 

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[woodpile]

Aaaarrgh! A beautiful weeping willow was felled near me, on a a gorgeous amenity value site. Sometimes it just has to happen. Over and out...

[kevinjohnsonmbe]

Thanks for 'taking the plunge' DT (sorry, don't know your real world name!) I've been a bit flat out today so hadn't had chance to start a thread.

 

I've just crash-read Mynors thoughts on assessment of amenity (The Law of Trees Forests and Hedges 2nd Ed section 22.2.6 p570-572) and requested the definition of “Amenity value” (of a tree/s) as it might be understood, interpreted and applied by my local authority - I'll post that up if I get something useful back.

 

I'm still thinking through what I want to say (truth be told, I'm not sure I know yet )

 

It's interesting, if I've interpreted it as intended, that I think your main thrust is determining a notional financial value. And I'd agree, that may be the main focus for the home owner - after all, money is the bottom line which will often over ride conservation / ecology ideals.

 

I'm interested in how the definition of amenity value might differ between the home owner, the local authority and the arborist. So, if a home owner (or a group of neighbours) is troubled by what may be perceived (rightly or wrongly) to be a hazard / nuisance, but the LA deems amenity value (perhaps in a Conservation Area) how is a 'value' assessed and what mechanism would be effective to take positives (eco, visual, biodiversity, general pleasure etc etc) and offset negatives (worry, light levels, leaves, sap, perceived hazard etc etc) to achieve a tangible output? And should it be multiplied by the number of people potentially gaining benefit and divided by the number of people having a negative experience. And how do you measure one person's pleasure against another's distress?

 

And then, as if that isn't difficult enough, should there be a different scale for urban and rural environments?

 

My head hurts!

[kevinjohnsonmbe]

And, I've just realised I'm a duffer because you sign off your posts 'Jules.' So, thanks for starting the thread Jules!

[bob]

I have looked at most of the tree valuation themes and I personally like the cavat as I really feel I can justify the process behind valuation and even the maths. But that is a tree cover valuation rather than a amenity valuation in reality IMO

Would it be missed if it went

Does it add to the neighbourhood

Does it need replacing

Is it worthy of a Tpo

That's more where I see amenity in that they are there for everyone rather than the individual who believes it affects them most wether they are the owner or not.

P.s

Do I need to sign my posts for you to know what my name is?

[kevinjohnsonmbe]

No, I'm all over it Dave!

[daltontrees]

A bit of an enigmatic question really, because you open with a hypothetical position - in so far that in it's healthy state, the tree would be "worth" £10k. But the tree isn't in a healthy state, so the hypothetical value is therefore irrelevant.

 

To those onlookers who haven't used valuation systems, the hypothetical position I think can illustrate an important principle that should always be present in valuations, and that is that the length of time that the benefits of a property can be enjoyed affects its value. What the Helliwell system does amongst other things is multiplies the value of a healthy tree by a fraction that reflects its short future. Thus a tree with long likely lifespan might have a value of £10,000 but one that is the same size you could only expect to have a less than unacceptable risk of 2 to 5 years has a Helliwell value of £10,000 x 1/4.

CAVAT does the same thing only, in my opinion, considerably better. iTree doesn't even try.

I agree with the principle more wholeheartedly than I do with any other aspect of tree valuation methodologies. iTree fails. CAVAT gets full marks and Helliwell gets half marks for trying.