UKTC Archive

Re: Diameter callipers

Subject: Re: Diameter callipers
From: Wayne Tyson
Date: Aug 15 2019 21:39:48
Thank you, Bill Kowalczyk, for your summary.

Perhaps you can further enlighten me.

What was/is the basis for the "rule of thumb"?

Is the 12 x stem diameter "rule" based on the tree's dbh at maturity?

Regarding ". . . roots beyond this zone may get trammelled *without
significant negative impacts* [[Italics mine]]on the health and vitality of
retained trees," on what basis was that determined?

Cheers,
Wayne

On Thu, Aug 15, 2019 at 5:49 AM Bill Kowalczyk <bill@xxxxxxxxxxxxxxxxx.co.uk>
wrote:

Hi Wayne,

The oft quoted British Standard; "BS5837:2012 - Trees in relation to
design, demolition and construction” came up with a calculation for
recommended root protection areas (RPA), which works out at a radius of 12
x stem diameter (but measured at 1.5m for some peculiar reason) for most
single stemmed trees.

In practice, with most trees, this invariably comes to about the same as
measuring to the “drip-line” of the canopy edge, and accepts that roots
beyond this zone may get trammelled without significant negative impacts on
the health and vitality of retained trees.

It’s a bit “rule of thumb” developed by the working group who first came
up with the standard back in the early 1990’s, but it’s all we’ve got and
better than nothing.

Cheers,

Bill

On 14 Aug 2019, at 23:55, Wayne Tyson <wt750mv@xxxxxx.com> wrote:

What does dbh have to do with RPA? What are the standards and upon what
data doth they rest? Protection from what, for example? That is, in the
simplest terms, other than dbh how are RPA's determined?




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