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<Russ Carlson>
posted
The 9th edition has offered a revised scale system for rating the Condition.

The 8th edition used 5 factors, each rated 0 to 5. The 9th edition uses the same five factors, but has separated three of them (Roots, Trunk, Scaffolds) into 2 groups- health and structure.

The problem I have with this is the weighting of the factors. All 8 categories (5 health, + 3 structure) are weighted equally. This means that a depreciation of foliage health carries as much weight as depreciation of roots or trunk structure.

Discussion, please: Should these factors all crry the same weight? Are structural defects more important than the health factors?

Example: Ganoderma on oaks will often destroy a root system, yet the foliage can appear normal until the most advanced stages. Root structure 1, foliage health 4. Let's say for the sake of arguement that all other factors get a 3. We have 23 points out of a possible 32, or 72 percent. Yet the condition of this tree is quite dangerous.

Other than the obvious responses- "It's only a guide" and "Apply professional judgement", is there a way this could be addressed?
 
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<lewbloch>
posted
Reply to post by Russ Carlson, on July 20, 2000 at 10:26:24:

Hi Russ,

Without going into detail, which is my style, as you know, the purpose of the new rating system is that it gives roots, trunk, scaffold branches twice as much weight as leaves and small branches. This is an improvement over the 8th where they all carried the same weight. Of course you are well aware that if the tree is dangerous, for any reason, it probably should not be appraised or even given a negative value.

lew
 
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<Russ Carlson>
posted
Reply to post by lewbloch, on July 20, 2000 at 10:26:24:

OK, Lew. I see I overlooked the obvious- if root or trunk structure is poor, the health rating probably will be, too. I'm just trying to figure how to build this into my software package.

One option is to not even include a rating for foliage, if it doesn't apply. It can be skipped if, for example, you assess in winter when leaves have dropped. Using the Guide as a guide, you would then tally the other 4 factors and divide by 28, instead of 32. This has the effect of giving more weight to the remaining factors.
 
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<Scott Cullen>
posted
Reply to post by Russ Carlson, on July 20, 2000 at 10:26:24:

I'll have to take a closer look at 9th Condition Rating Scale. But in general, this is one instance where "it's only a guide" may be the most appropriate rule. Whether the simply table discussed here or a more detailed protocol as in the MN supplement, in my opinion these should be no more tha checklists of characteristics to be considered.

There is much too much danger that the appraiser will take the point ratings as the only possible, proper depreciation... either more or less depreciation being sub-standard.
This is embodied in the idea that there is a right or wrong rating, weighted or otherwise, that will pop out of the list.

Take a simple and obvious methodological problem inherent in both 8th and 9th. Both editions allow the apprasier to start with wholesale, retail or installed costs. Assuming value is what it is and you have to depreciate to that number, that means there are at least three different ratings that are "right."

There is something of a Catch 22 in a depreciated cost methodology. Cost must be reduced to reflect value but there is something of an assumption that you know what value is in order to get there. Crystal ball? Maybe. But fixed ratings are no better. The appraiser has to look to either other approaches and compare indications or to other facts. Does the treee have maybe 5 years left to live? Translate that into a reduced value. Does the tree have very little contribution because it's across the river and through the woods and grandma never even saw it because it's across the swamp too? Reduced value. Could it live for 20 years, but maybe it could die from DED this season? Maybe there's a scheduled discounting of possible expected benefits in each year.

I don't think the answer is in a signle rating scale without consideration of other indications and facts.
 
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<lewbloch>
posted
Reply to post by Russ Carlson, on July 20, 2000 at 17:58:13:

Hi Russ,

Yes, Yes, Yes, and Yes!

lew
 
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<Scott>
posted
Reply to post by Russ Carlson, on July 20, 2000 at 17:58:13:

Good point Russ. It has always concerned me when tables require a point score for foliage which is unobservable in the dormant period for deciduous plants. Null data is not the same as a zero rating.

I'll check the MN supplement... they may have addressed this.

On a related note, I'm also concerned that there is a bias that big foliage and long twig growth increments or wide annual rings are good and so the opposite must be bad. Some very successful plants survive by very slow incremental growth... the benefits they deliver and will continue to deliver are not reduced by small growth increments.
 
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<Russ Carlson>
posted
Reply to post by Scott, on July 20, 2000 at 23:39:49:

Whenever comparing a tree to a rating scale, it must be by species and cultivar (if applicable). Four inches of twig growth would be downright excessive on a dwarf Alberta spruce, paltry on a metasequoia. There is not one 'right' rating. And this, my friends, is what keeps keeps us in business.
 
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<Scott>
posted
Reply to post by Russ Carlson, on July 22, 2000 at 06:28:53:

Absolutely. But I was actually thinking of specimen to specimen considerations. A young tree in a fertile location might be expected to have relatively rapid growth. If it doesn't we might suspect some problems. Same species when older or at the seashore or in a rock crevice might have a slow steady growth rate that indicates no problems.
 
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<Russ Carlson>
posted
Reply to post by Scott, on July 23, 2000 at 20:07:13:

A good point. We are now down to the difference between vigor and vitality, and how we enter that into the Rating scale.

Vigor is a measure of how well the individual is doing with the resources it has. Slow growth may not indicate poor vigor, just limited resources.

Vitality is the full potential of the tree, how well it can do in an unlimited situation, or if the limits were removed.

So if we are judging a tree in a crack in the rock, and it is growing slowly, does that get a lower health rating for roots, since the soil is poor and limiting growth? Or a higher rating, because slow growth is not the same as poor health?
 
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<Scott>
posted
Reply to post by Russ Carlson, on July 24, 2000 at 07:48:03:

I've never fully accepted that Shigo's vigor-vitality distinction should be a hard rule. It may be a useful tool in understanding. I wonder if we sharpen the point to much in some of these rating scales. Do we need to understand more than whether the tree has physiological (health) problems (as contrasted to structural charcateristics) that make it deliver fewer benefits (shortened lifespan, thin canopy, poor appearance, etc.)? This may be one of the instances where it is unimportant which word we substitute for "health" and long as our choice is not confused with something else.

A stunted tree in a crack in the ledge has a limited root system. Is that cause or effect or both? Does it matter? In a cost approach the main limiting factor will be size. Does the beneficiary find value in this tree becasue of it's artful placment in the rock garden? Or does the beneficary really want a bigger shade tree to protect the bog plants in the wetland garden (going to plant a fast grower to get it and it will shade out and kill the stunted tree in a few years)?

Is this question better appraoched by making a vigor - vitality distinction within Condition or by considering Contribution and intended use? Dunno? Maybe both. Or maybe simpler is better.
 
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<Russ Carlson>
posted
Reply to post by Scott, on July 27, 2000 at 00:31:00:

And now we've come full circle. The answer is "there are no answers, only more questions."

The rating scales, how and when to apply which method- all these things require thought and consideration, and a rational approach, based on the facts and the assignment. What works best in one case may not work at all in another. This is why training and experience are so important. Understanding the formula is not enough- it is imperative to understand the whole process and the theory, in order to apply it properly and to the best advantage.
 
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<Scott>
posted
Reply to post by Russ Carlson, on July 27, 2000 at 09:08:11:

Yes indeed! That's the very idea I posed in 1998 in a "Location" thread started by Tina Cohen:
http://tree-tech.com/board/?topic=topic1&msg=193

And posed the most basic question "What is Value?" at:
http://tree-tech.com/board/?topic=topic1&msg=196

Actually, there are answers, there just are not exclusive answers or single "right" answers. There are "right" questions in that they are logically posed. There are wrong answers in that they are not based on sound questions and sound understanding of facts.

The lack of single, universally applicable and "right" answers does NOT mean the appraiser can just make up anything becasue the "Guide is only a guide is only a guide." That's a crutch and is unsupportable.

Your question in this thread was specific to 9th Edition Condition Rating scales. The discussion has really gone back to underlying valuation.... maybe any continuation should go back to that topic area. Maybe pick it up where we started: What is value?
 
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<Julian>
posted
Reply to post by Scott, on July 27, 2000 at 22:47:33:

All worthy points, but perhaps one of the most important ones for me was the idea that we "sharpen the point" too much. In any assessment / evaluation approach there will never be perfect knowledge, only an approximation of this based on a mix of subjective and objective factors. There is a tendency to assume that the mere presence of a structured approach, such as the Trunk formula, and its "look" of an objective mathematical model, will yield a definitive answer.

Nothing is further from the truth. All of the so called objective inputs are based on an appraiser's subjective interpretation of what % of a factor to use, and how. In many cases, the level of detail available in the new approach is utterly irrelevant in the type of trees we have round here.

I think it may be leading the appraisal process into increasingly uncertain waters if we keep trying to reduce these factors into more and more subsets. For anyone with the time, try using the TF approach as a modelling tool. Vary one factor at a time and run the calculation iteratively. Compare the end answers over a range of variations. Then compare the range or spread of the end results with reality. Does it really make that much difference if the answer is plus or minus $ 5,000 ? $ 10,000 ?

The point of the exercise is to try and derive a "reasonable" approximation of value, not the definitive value - the latter is purely hypothetical and can never by quantified. The former is what the appraiser is trying to determine, and will hope to have used in the court, where eventually, the judge and /or jury will decide if it makes sense.

We need to keep a sense of proportion in all of this. While we all accept that trees have value, I seriously doubt that some of the numbers I see bear any relation to reality.

Julian
 
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<Scott Cullen>
posted
Reply to post by Julian, on July 28, 2000 at 07:36:33:

Very well stated.

We should be trying to arrive at a "reasonable" result. Reasonable in the context of the facts. The facts are objective: tree of X size and Y species; located in the middle of a maintained landscape of a house that costs Z$; or located on a rural roadside; no decay observed, consistent twig elongation.... maybeyou can even say it's in "good" condition objectively. Turning location and condition into depreciation %ages or amounts becomes quite subjective in most cases (an exception might be if the definition of value that is contribution to real estate market value and we have good data on that value and on typical contributions).

I agree we might have different iterations or different approaches and these could all be presenetd to the decision makers (judge, jury, parties, owner). Value is by its very nature subjective... it varies by the subject tree and the beneficary. It is subjective to the person who experiences it. So you're right, there is no definitive answer... until the decisionmakers create the fact of value... by verdict, by settlement, by exchange at a price... whatever.

A value is not necessarily reasonable if it pops out of a textbook formula (the excessive opinions you describe) nor is it reasonable if it's so low nobody will disagree (except maybe the damged party who isn't made whole).

Value opinions are not reasonable simply becasue the come out of an allegedly "objectified" process that is merely arbitrary or hides facts in tedious analysis. I agree, that risk is quite present in increasingly complex tools unless accompanied by basic understanding of value.
 
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