UKTC Archive

RE: Plotting groups

Subject: RE: Plotting groups
From: Ben Rose
Date: Dec 15 2008 11:42:46

Hi Brendan,
In my opinion in some circumsatances it is appropriate to group trees. In 
particular when trees are of the same species or they have grown up together 
and when they should be managed as a group. I know of many other 
arboriculturists that group trees and I believe that it is common practice.
When surveying a group of trees for risk you should look at each tree in the 
group individually. If any trees have signs of structural weakness, or if 
they require particular management, they should be surveyed individually; 
otherwise you should make general condition notes and recommendations for the 
whole group. I think that this is an acceptible methodology despite the fact 
that the trees will not be exactly the same in form, condition or location.
In my opinion, if one tree in a group was to fail the situation should be 
similar to an individually surveyed tree failing. That is to say that the 
relevant questions in any investigation would be - were there any obvious 
external indicators of structural weakness visible at the time of inspection? 
and, given the circumstances was this tree failure foreseeable?
On this basis I see no problem with surveying trees as groups.
Date: Fri, 12 Dec 2008 11:55:14 +0100> From:> 
To:> Subject: Plotting groups> > Question: Tree 
databases.> > Plotting trees in groups is more cost effective. It provides 
data > which is easy to understand and easy to re-visit, (especially when > 
compared with lots of confusing, individual records). But does a > 
methodology which promotes the surveying of the majority of trees as > 
groups, offer a robust defence against litigation?> > Let’s say, “Bob” 
surveys 10 trees in a collective group. They are > generally in fair health 
but with some minor defects. They are located > next to a public highway. 
Bob surveyed them all in detail at the time > of inspection, but the 
methodology requires one generalised record for > the collective group. We 
know that all trees are slightly different > and a single database entry 
for a group of trees will only ever record > the “average tree” within the 
group. > > Now lets say one of the trees, fails. The expert witness for the 
“other side” says what he is paid to say, “there was clear evidence > 
that the tree would fail.” If we assume that “Bob” surveyed the trees > 
properly (and yes, with hindsight, the tree should have been plotted as > 
an individual, but the same applies to most of the others), is there an > 
obvious problem with a methodology which promotes plotting trees as > 
groups wherever possible? Will such a methodology provide a robust > 
defence against litigation? > > Now lets apply the same scenario to a 
woodland. There are over 1,000 > trees and again, a general note appears 
within the database. One of > the trees fails…> > Any thoughts?> Brendan> > 
Discounted hotel bookings -> 
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