daltontrees

OK so I didn't expect overpowering enthusiasm for this subject but I am quite dismayed by the general lack of interests. If anything I am surprised how anyone can get through a working year in arboriculture without bumping up against the subject and having to have a rudimentary understanding of it. But that's maybe just me... A fair question then would be, why do we need valuations? To explain that, an understanding of what valuations are is needed. So here's my grossly oversimplified explanation. They are imitations of what would happen in the marketplace. That term 'marketplace' is used for global financial markets but we shouldn't overlook its origins in (say) a simple town market where buyers and sellers come together. Say ten sellers turn up with a cart of apples each and ten buyers turn up with empty carts looking to fill them with apples. Happy days, supply equals demand and the highest price will be paid for the best quality apples by the most discerning buyer. The lowest price will be for the desparate sale of the half rotten cartfull that the buyer only needs for pigfood. But somewhere in the midst of it all we can sense a market price for apples there at that time. So a seller or buyer comes home and his neighbour asks him 'I have a cart of apples to sell next week at that market, how much will I get for them?'. Our man, fresh from the cut-and-thrust of the market, tries one of the apples and gives his neighbour an estimate of what he thinks the cartfull will fetch. And that is a valuation. An up-to-date, informed imitation of the market. Lesson one, valuations are only good for a time and a place. Of course, there is no guarantee that that is the price that will be fetched. Say the seller turns up, the only seller that day, and ten desparate buyers turn up. The 'laws' of supply and demand suggest he will get a very very good price as the buyers compete. But say he turns up with nine other sellers and there is only one buyer. That buyer will smile to himself and systematically bargain the sellers down to a very good price. Lesson two, valuations are only as good as the assumptions that you make about the balance of supply and demand. The seller also brings along a cartfull of pears, thinking he will get the same price as for apples, they're all fruit, after all. But no-one wants pears that day. He tips the lot on the way home, disappointed. Lesson three, don't use apples to value pears. Bear with me, I will get around to trees eventually...

Amazing alliteration! I like questions, basically I get excited by the subject of valuation and am astonished and delighted when anyone else is. So fire away anytime, I might not have the answer but I will try.

Almost certainly Ganoderma applanatum, have a search in the Fungi Directory for general prognosis (not good)

Have a look at the fungi directory on this site. C. micaceus is listed there. It doesn't look like a perfect match for your pics. But even if it is it is a mildly saprophytic fungus. feeding on dead material rather than killing. So it could be causing ofr contributing to the rot but I would very very much doubt that it is causing the fundamental problem with the tree.

Now I see why nobody's ever posted about tree valuation before. Almost complete apathy about the subject amongst tree surgeons and tree workers. Oh well... So now that I have a forum thread with tumbleweeds blowing through it I can indulge myself by filling it full of whatever I consider might be useful to anyone in the future looking for a bit of background information. I will concentrate on a few specific themes how does the value of trees relate to the value of the land it is situated on (and vice versa)? how does it relate to the value of other land and public places (and vice versa)? what systems are currently used and what are their main features? what is good and bad about existing systems? what can be done about it? (chirrip.... chirrip)

Doesn't look anything aggressive. Doesn't look even like the usual suspects for feeding on deadwood. There's a big difference between causing decay and living on dead material. Perhaps the decay is being caused by something else and your mushrooms are bit-players in the background?

David, hope you don't mind if I pitch in? I think the use of the words 'reactive wood' could turn out to be unhelpful and confusing. There are the established terms of 'adaptive growth' and 'reaction wood'. The term 'reactive wood' is new to me. If your definitions opened with 'Formation of additional or specialised wood as a reaction by the tree to abnormal external forces....' then I think it would be a reasonable summary. I have always struggled to understand the difference between 'adaptive growth' and 'reaction wood'. The former should probably refer to the general habit of trees of self-optimizing (axiom of uniform stress etc.) by adding to their structure to compensate for forces that would otherwise compromise them. It is, however, also used by many people to mean the extra wood itself. It is further used to describe extra wood, specialised or otherwise, that has grown as a quick response to partial structural failures such as at compression forks or at decaying unions. 'Reaction wood' really ought to be saved for describing specially adapted wood. As you have said in your ddescriptions, the wood may be especially rich in lignin or cellulose. But there are other adaptations too in the orientation of fibres and cellulose in cell walls. Cells may be shorter, they may also be rounder. They almost certainly will expand (compression wood) or contract (tension wood) on maturity. That's where the push or pull comes from. All the other specialisations I have taken to be to provide additional strength, not push or pull. As such, I would disagree with the exact wording you have put forward, but only in a pedantic way because the cellulose or lignin does not push it only gives strength to the cells so that when they pull or push by shrinkage or expansion they do not fail. Things get complicated with the terminology in practice. Reaction wood tends to be added with unusually wide annual increments and so can appear just as extra wood. But if you try and put a saw through a branch union of a broadleaf you will soon know that you are encountering extra cellulose. Similarly with a conifer you will sail through the reaction or compression wood relative to the normal wood because it has more lignin that cellulose. It is like a linear resistograph test, you just need to listen to the saw revs to gauge the relative cellulose content. At least, that is how I amuse myself when discing stuff. So in summary my definitions are roughly - adaptive growth is the addition of extra wood (a process, not a substance), reaction wood is specialised wood, compression wood (in conifers) is wood arising from adaptive growth usually including the addition of lignin-rich reaction wood, and tension wood (in broadleaves) is wood arising from adaptive growth usually including the addition of cellulose-rich reaction wood. I am open to any other suggestions or refinements.

Ta, Rob, I think you're right. Leccinum scabrum. Could be quite tasty.

And just across the gorge under mixed Pine/Beech/Birch and Rhododendron was this pair.

This Bolete was spotted atthe weekend near Blair Atholl. Pretty soggy underneath and as it was beside a nature walk I didn't want to uproot it for a better look. Any idea what species, anyone? The Directory has the most likely candidate B. edulis as under broadleaf but occasionally under pine, but this one was under exclusively larch.

Found on Scots Pine near Boat of Garten (near Aviemore). Looking a bit old. Would this be Phaeolus schweinitzii?

Further to other pople's and my pics of Amanita muscaria, here's another taken near Dunkeld at the weekend, underneath Larch and Scots Pine. Previous pics were underneath Birch/Alder/Willow/Hazel. Just goes to show it's not fussy about soil.

I think that falls into the tools for the job category, as long as you state what your figures cover and don't cover there is no problem. Except as ever that valuations are not valuations if they are not rooted, literally and metaphorically, in the legal control of the land on which the tree or trees are situated. In effect you are trying to put a figure on the benefits that everyone gets from a tree, which has very very little relationship to the value of the tree to the owner. As long as you keep calling that 'assigning a financial value' instead of 'valuing', it's sound. As to which of these factors are amenity ones, wellbeing/feelgood definitely is. That seems to be what amenity is all about. Property prices are a reflection of that rather than another factor.

Here's the case. The court accepts broadly that the neighbouring property before the illegal removal of the neighbour's tree is £50,000 less than after its removal. r v davey.pdf

Been there too, 20 years in and out of local government (or public service as I stilll naively like to call it), I have sympathies in both directions. I am reminded of the origins of the Hellliwell system. It started off as a way of assessing the relative amenity of trees, I think as a means of deciding whuich should be proptected and which shouldn't. It gave each tree a number of points based on size, position, form etc. I find it hard to fault it (except on a few matters of subjectivity) for that purpose. But then decades later someone decided to attach a £ per point and call it valuation. A quite arbitrary £ per point. That does not make it a valuation. That makes it a monetised amenity assessment. That's where all the confusion started, as far as I can tell. Like nailing a hundred bits of wood together, sticking it in the ground and calling it a tree. Sorry, but that's called a fence.

I think what troubles you is what troubles everyone. Putting a £ value on amenity. But as soon as a TPO'd tree is removed without consent and a measure of the penalty is required, people will try. Which reminds me, did you see the recent appeal court case in Poole, Regina v Davey? It could be a useful one for people to look at here?

Out of curiosity do you work for, or have you worked for, a Local Authority? I think you have listed the right questions but I think they can all be rephrased as follows - How much would it be missed if it went, and by whom. And for how long? How much does it add to the neighbourhood? How badly does it need replacing, and how urgently? By a replacement of the same size and species? How worthy is it of a TPO? And what difference does that make to the value? And you didn't mention the poor owner... And now my head is starting to hurt.

There should be! But Helliwell doesn't try. CAVAT sort of tries insofar as it multiplies the tree value bya rounded-off factor that reflects the population density of the local authority area. Which is a decent stab at the problem but doesn't work for anything other than LA accounting. And the resultant number is as consequence arbitrary. It is incapable of being tested against market values or costs and therefore is not really a valuation. It is, however, a measure of worth (see earlier comment to Mr Clark) if the LA accepts it to be one.

That is my main thrust, not because of the rather distateful bean-counting tendency in modern life to reduce everything to a financial decision but because I don't see any other way of weighing up costs, private amenity values, public amenity values, risk management decisions etc. They must surely all be measured in the same units and the same currency, and all be capable of being related back to testable market values or market costs?

I agree that CAVAT is useful for LAs. I don't think it has any other use. CTLA I believe is the future, it is the only system that is a true valuation rather than a monetised amenity assessment. iTree seems to be a monetising system too. So which tool is the right one for the job here on my hypothetical tree? What if Helliwell produces £2,500 and CTLA produces £1,000? It could be life or death for the tree.

One might also consider the gambling involved in retaining the tree. If there is a 1:20,000 risk of it killing someone and triggering a £1M law suit, the cost of that risk is perhaps 1/20,000 of £1M which equals £50 a year. That is what I see the QTRA approach as doing or allowing you to do.

My hypothetical tree has Meripilus, let's say it is not practical to try and ameliorate its environment and that investigation shows that the underside of roots and butresses are in a fairly advanced and untreatable stage of decay. I am guessing form what you say that you would expect the cost of treatment to be uneconomic, exceeding the value of the tree. Valuers make a very specific and important distinction between 'value' and 'worth'. For that reason as an ex property valuer I get really cheesed off with the 'how much is a tree worth?' debate. It is worth £x to the owner. It is worth £y to the neighbour. It adds £z to the bids that the house would get on the open market, which is what it is worth to the highest bidder in addition to a hypothetical treeless house. And it is worth £w to the public, which if this is high enough will probably get it TPO'd. It's worth nothing to the arborist except as a source of profit for felling or pruning it. These are all measures of worth. Not of value. The value is ....?

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.

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?

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.