UKTC Archive

To: "UK Tree Care" <uktc@xxxxxx.tree-care.info>
Sent: Sunday, July 05, 2009 8:08 PM
Subject: Re: What does likelihood mean


Having used the word 'LIKELY' in a report and court once before (some 12
years ago), I would now say the word is meaningless and ambiguous so why use
it. Unless you you have no idea what you are talking about? As for the word
'LIKELIHOOD well you could draw your own conclusions as others have....enjoy

To: "UK Tree Care" <uktc@xxxxxx.tree-care.info>
Sent: Sunday, July 05, 2009 7:40 PM
Subject: Re: What does likelihood mean

 To: UK Tree Care
 Sent: Sunday, July 05, 2009 1:47 PM
 Subject: What does likelihood mean


 MB-T: Two things have been puzzling me

 MB-T, 1: If likelihood of failure is based on occurance within a
population does this
 mean we can reduce the likelihood of tree failures by planting more trees
 and therefore increasing the size of the population.

 SC 1:  If a) the new plantings are additions and not replacements, and b)
each of the additions have a lesser likelihood of failure under similar
loading conditions, then yes the TREE population just achieved a lower
likeliehood of failure.  Of course this ignores at least a couple of things,
including c) whether managment is or should be based on that model of TREE
popullation risk of failure, d) whether management in that model is or
should be based on the entire population or rather stratified by age, size
or other cohorts.  And it ignores a bigger background question:  e) whether
risk or likeliehood should be calculate or estimated on TREE population, as
above, or on harm or damage to the TARGET populations.
 SC 2:  Another question is whether there is a preferred managment model
for all seasons, or if the prefreered managment model allocates varaiblly
available resources to variable sorts of tree (old, young, large, small,
species profile) and target populations (urban, rural, dense, sparse, etc.)
under different loading conditions.  Current world economic conditions which
have governments reducing police, fire, hospital, school and other
employmeny and companies going belly up or furloghing valued staff raise
lots of questions about acceptable or tolerable risk.

 MB-T, 2: If the likelihood of failure of a tree or part of a tree is say 1
in 400 and
 this leads to unacceptable risk does this mean we do work on or even fell
 400 trees because one tree failed?

 SC 2:  Which management regieme above?  Which 400?  What if available
resources allow for abating 200 risk and that is only after sacking two
firefighters?  The question is too simple to allow any meaningful answer?

 SC 3: enough variables to drive a modeler like Marcus a bit nuts.

 Scott Cullen

 Regards

 Marcus

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To unsubscribe send mailto:uktc-unsubscribe@xxxxxx.tree-care.info

The UKTC is supported by The Arbor Centre
http://www.arborcentre.co.uk/