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Neighbouring Trees and TPOs


Derek Eames
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11 hours ago, TreeSquirrel said:

It was a tree expert he said it was over the next thirty to forty years it is the prunus family

Either the measurements are incorrect or the chap you spoke to isn’t a tree expert. Even if you have confused inches with cm’s, a prunus isn’t going to go from 40 - 80 in that time frame.  Arb experts don’t measure stem diameters in inches either, or cm’s for that matter.  Anyone who surveys trees in an Arb context will always discuss diameters in mm’s just out of habit after a while. 
 

Dan is correct, you should get someone to look at it objectively. Not someone who is quoting to fell.  This is especially important if you involve a solicitor and end up going to court. Court compliant reports should be written in accordance with CPR 35.  This is high end consultancy realistically.  

 

 

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On 19/07/2021 at 09:33, Chris at eden said:

 Arb experts don’t measure stem diameters in inches either, or cm’s for that matter.  Anyone who surveys trees in an Arb context will always discuss diameters in mm’s just out of habit after a while. 

Oh no they don't! Measuring stem diameters for routine arb purposes in mm is simply one of the silliest things I have seen. If someone was measuring the growth of a tree in a permanent sample plot, measuring and recording mm is possibly justified; otherwise it's simply a waste of paper and/or data memory. Yes I know what BS5837 but it simply tells us that its authors knew little about tree mensuration, statistics and data. Measurement to the nearest 10 cm is possibly good enough for most purposes, rounding up. As for branches on complex stems such as cypresses......

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1 hour ago, Jon Heuch said:

Oh no they don't! Measuring stem diameters for routine arb purposes in mm is simply one of the silliest things I have seen. If someone was measuring the growth of a tree in a permanent sample plot, measuring and recording mm is possibly justified; otherwise it's simply a waste of paper and/or data memory. Yes I know what BS5837 but it simply tells us that its authors knew little about tree mensuration, statistics and data. Measurement to the nearest 10 cm is possibly good enough for most purposes, rounding up. As for branches on complex stems such as cypresses......

Silly or not, it's in the Standard to measure in mm. Rounded to nearest cm, so it's effectively not any more precise than cms. Rail against it if you want, but best just to do it anyway. Seeing reporting in cm is kind of annoying, it suggests the report author doesn't know or respect the Standard. Reporting in inches, you'd have to be in the dark ages or in America, possibly one in the same...

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1 hour ago, Jon Heuch said:

Oh no they don't! Measuring stem diameters for routine arb purposes in mm is simply one of the silliest things I have seen. If someone was measuring the growth of a tree in a permanent sample plot, measuring and recording mm is possibly justified; otherwise it's simply a waste of paper and/or data memory. Yes I know what BS5837 but it simply tells us that its authors knew little about tree mensuration, statistics and data. Measurement to the nearest 10 cm is possibly good enough for most purposes, rounding up. As for branches on complex stems such as cypresses......

Oh yes they do, he's behind you!  Sorry thought we were back in panto season.  

 

I don't know what you are talking about to be honest.  I didn't say using mm was sensible or silly or anything else.  I simply said it is what Arb experts do.  You actually allude to this in your first sentence when you say using mm's routinely in Arb is silly.  It may be, but they do.      

 

5837 uses mm's.  As does QTRA.  Planning related information must (I am told) be submitted using metric measurements which OK you could use cm's but when was the last time you saw a scale rule with cm's on it?  CAD drawings from architects use mm's as do engineering drawings usually - and they know nothing about measuring I suppose?  Why would we use something different?  My point was that they don't use inches, and no nor do they use cm's often as far as I can see.  The only Arb inspection system to my knowledge that uses cm's is the Picus software.  

 

If you measure to the nearest 10cm (100mm) rounding up then trees on development sites with a stem dia of 220mm would have RPAs increased from 2.7m to 3.6m, that isn't going to go down well with developers across the whole site.  Again, i am not saying it is right or wrong, just that it is standard practice in Arb to use mm's, not inches to measure stem diameters.  

 

Your comments about multi-stem calculations (I think that is what you meant) I agree with to be fair but it still standard practice.  This is actually one of the silliest things I have seen.  

 

Cheers 

 

Chris 

 

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15 hours ago, Chris at eden said:

5837 uses mm's.  As does QTRA.  Planning related information must (I am told) be submitted using metric measurements which OK you could use cm's but when was the last time you saw a scale rule with cm's on it? 

 

CAD drawings from architects use mm's as do engineering drawings usually

Depends what you use to measure your diameter with, but what unit does a diameter tape use? What does every forest mensuration and yield table use? That's because they have scientists, mathematicians and practical statisticians supporting them - they understand what they are doing and trying to achieve. They understand that data collection costs money. Use of an extra digit to report in mm is simply a waste of time & effort. It adds nothing.

 

For a very good reason; they are interested in accuracy in mm when installing buildings, measuring elements of the building to the nearest mm. Not micro metres that a mechanical engineer might be interested in. It's horses for courses.

15 hours ago, Chris at eden said:

 

Why would we use something different? 

 

If you measure to the nearest 10cm (100mm) rounding up then trees on development sites with a stem dia of 220mm would have RPAs increased from 2.7m to 3.6m, that isn't going to go down well with developers across the whole site.  Again, i am not saying it is right or wrong, just that it is standard practice in Arb to use mm's, not inches to measure stem diameters.  

 

Your comments about multi-stem calculations (I think that is what you meant) I agree with to be fair but it still standard practice.  This is actually one of the silliest things I have seen.  

Why use something different? Well indeed, why has arboriculture wandered off by itself without thinking what was needed? Measurement systems reflect the need for accuracy and precision. Arboriculture gains nothing from trying to measure and record in mm. Nothing, other than larger bills as extra time is required to record an extra, useless digit. Greater potential for error, with an extra digit, repeated thousands of times per year. This is basic data recording theoretical, yet practical stuff.

 

As it happens my excel spreadsheet for BS5837 uses mm as the formulas are set up using mm. It's a joke & only done because I know someone may make the comment...well the standard says....

 

Recording tree diameters as 15, 20, 25, 30 cm does as you say have the potential to increase RPAs somewhat, if developers ever paid any respect for such measures. The significance of this for small trees is very small as branch length is typically greater than RPA radius (so the RPA actually misleads); for larger trees the % change is small. But if you have arb consultants allowing foundations to be dug on the edge of an RPA you need to add as much as you can, knowing how much liberty will be taken downstream.

 

>> No I am referring to a bog standard leyland or lawson cypress with no access to the stem as multiple branches prevent access and in reality it is not possible to distinguish branches from main stem. No need for a second or multiple stem for this problem to occur. Ridiculous to think of a measurement in cm let alone mm.

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23 minutes ago, Jon Heuch said:

Depends what you use to measure your diameter with, but what unit does a diameter tape use? What does every forest mensuration and yield table use? That's because they have scientists, mathematicians and practical statisticians supporting them - they understand what they are doing and trying to achieve. They understand that data collection costs money. Use of an extra digit to report in mm is simply a waste of time & effort. It adds nothing.

 

For a very good reason; they are interested in accuracy in mm when installing buildings, measuring elements of the building to the nearest mm. Not micro metres that a mechanical engineer might be interested in. It's horses for courses.

Why use something different? Well indeed, why has arboriculture wandered off by itself without thinking what was needed? Measurement systems reflect the need for accuracy and precision. Arboriculture gains nothing from trying to measure and record in mm. Nothing, other than larger bills as extra time is required to record an extra, useless digit. Greater potential for error, with an extra digit, repeated thousands of times per year. This is basic data recording theoretical, yet practical stuff.

 

As it happens my excel spreadsheet for BS5837 uses mm as the formulas are set up using mm. It's a joke & only done because I know someone may make the comment...well the standard says....

 

Recording tree diameters as 15, 20, 25, 30 cm does as you say have the potential to increase RPAs somewhat, if developers ever paid any respect for such measures. The significance of this for small trees is very small as branch length is typically greater than RPA radius (so the RPA actually misleads); for larger trees the % change is small. But if you have arb consultants allowing foundations to be dug on the edge of an RPA you need to add as much as you can, knowing how much liberty will be taken downstream.

 

>> No I am referring to a bog standard leyland or lawson cypress with no access to the stem as multiple branches prevent access and in reality it is not possible to distinguish branches from main stem. No need for a second or multiple stem for this problem to occur. Ridiculous to think of a measurement in cm let alone mm.

I agree, it’s not so much a discussion about how it’s done, but rather why it’s done that way. 

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