Summer Branch Drop

[htb]

Is this the new Trigger and eggs thread?

[Acer ventura]

I've heard similar anecdotes.

 

I suspect sheep just bolts soon as they hear a crack, whereas people are likely to stop texting and look up.

 

In this video, the dog makes a much better decision.

 

I've heard one story of someone getting killed by a branch because they had headphones on didn't hear the crack that their friends did which had them move.  However, it might be apocryphal because I've not yet found it on the interweb.

[Canal Navvy]

58 minutes ago, daltontrees said:

I was out on a survey in the north of Scotland last week, the farmer's wife told me last year they had a tree at the end of the garden, one evening they heard a bang, went out the next day and the tree had been hit by lightning and exploded into lots of bits. As they cleared up the mess they found a cow and calf dead underneath. She said they couldn't tell if tthe beasts had been killed by the lightning or the tree but she had seen them sheltering under the tree earlier.

Pretty academic if they died from the lightning strike or the falling debris, must have had little reaction time either way. The mother didn't seem to have any supernatural forsight, which could suggest that the sheep that leg it are aware of odd noises above  and are poised for flight.

 

If sheep have really fast reactions (and no baggage to gather up of course) then it is of little help in reducing risk to humans as it's not how humans react. The only thing to do is to prevent humans being there in the first place. 

 

If those sheep are aware of noises above prior to the failure then there would be potential to monitor typical limbs in high footfall ares for signs of impending failure by listening to them electronically possibly ?

 

 

 

 

 

[Watercourse management]

A ten year old boy was killed in late June 2007 and two of his class mates hurt after a beech tree suddenly dropped a branch on a national trust estate in Norfolk.

[openspaceman]

12 minutes ago, Canal Navvy said:

Pretty academic if they died from the lightning strike or the falling debris, must have had little reaction time either way.

True but the problem with cattle is they make good ground contact and if a tree nearby is struck there is a current spike that radiates from the tree, causing a considerable voltage difference over a few feet and there are not many ways the beast can stand without the voltage between two feet causing a current to run through the heart.

Edited July 18, 2021 by openspaceman
spelling

[Acer ventura]

2 hours ago, Mr. Squirrel said:

You're very critical of the sign in the photograph, but are you familiar with the site history? You state in your SBD guide that 'If any of our trees have a history of SBD then we'll manage the risk to an Acceptable level'. So what's to say that this tree hasn't historically dropped a large section?

Good points.

 

The tree hasn't dropped a large section.  Nor the tree next to it that has the same sign.

 

Other much larger trees on the site have dropped large limbs and none of them have SBD warning signs under them.  Most likely during storms, but some may have been dropped in calm hot conditions outside of storms.

 

The critical point about the sign is it's ineffectually managing the risk and making the duty holder MORE vulnerable to a claim being made in the extremely unlikely event of the risk happening.

 

All of the biggest trees don't have any SBD signs under them.

 

Why is it okay to walk under the trees but not sit?

 

Can you stop for a chat, or dwaddle?

 

If sitting is too high a risk and walking is an Acceptable or Tolerable risk, how was that difference in the likelihood of occupancy changing the risk from being Not Acceptable or Not Tolerable to Acceptable or Tolerable worked out?

 

Had the tree had a history of dropping limbs after bouts of hot dry weather, then given its location a risk-benefit assessment would've been necessary.  The risk would've needed to be managed by fencing off/mulching (people are reluctant to sit on mulch), or pruning, or felling.

 

<<I've witnessed SBD on 3 occasions, but I've never witnessed a failure due to decay first hand. Anecdotally that would suggest that if the risk of SBD is 'mind-bogglyingly low' then the risk of failure due to decay is... bamboozlingly low? I'm not sure what the technical term for this level of risk would be in the VALID system.>>

 

A quick point of clarification.  The risk from SBD is the likelihood of someone being there, the tree part falling, and then causing significant consequences.  Likelihood of failure is not the risk.

 

As for your experience.  The risks we're dealing with are so mind bogglingly low that none of our first-hand experiences, mine included, are likely to be representative of the underlying truth because of the small sample size.  What we do know (citations in the SBD Guide) is that of the 64 deaths over 10 years in the DARM database they put together for the National Tree Safety Group, none of them sounds like anything close to SBD.  Similarly, when the database for Australian trees deaths in coronial inquests since the 1870s is searched, and wind being a factor is filtered out, there's a similar magnitude of order lower than our base rate from ALL deaths by tree failure by x10 or so.

 

Edited July 18, 2021 by Acer ventura

[Acer ventura]

20 minutes ago, Watercourse management said:

A ten year old boy was killed in late June 2007 and two of his class mates hurt after a beech tree suddenly dropped a branch on a national trust estate in Norfolk.

Yes, that went all the way to a civil court case, Harry Bowen and Others v Felbrigg.  But it wasn't claimed to be SBD that caused the stem to fail though.  There was a tremendous and sudden squal and a tree risk feature that couldn't reasonably have been picked up from the ground.

 

I remember talking to a couple of local Arborists at the AA conference not long after the court case and they said the squal that ripped through and caused this tragedgy left a distinct path of tree failure in the area.

Edited July 18, 2021 by Acer ventura

[daveatdave]

i have noticed sbd seems to happen after a hot dry spell (like now) then it starts raining  a day or so later down they come 

[Stubby]

7 hours ago, daveatdave said:

i have noticed sbd seems to happen after a hot dry spell (like now) then it starts raining  a day or so later down they come 

yes that is it .

[Mr. Squirrel]

20 hours ago, Acer ventura said:

Good points.

 

The tree hasn't dropped a large section.  Nor the tree next to it that has the same sign.

 

Other much larger trees on the site have dropped large limbs and none of them have SBD warning signs under them.  Most likely during storms, but some may have been dropped in calm hot conditions outside of storms.

 

The critical point about the sign is it's ineffectually managing the risk and making the duty holder MORE vulnerable to a claim being made in the extremely unlikely event of the risk happening.

 

All of the biggest trees don't have any SBD signs under them.

 

Why is it okay to walk under the trees but not sit?

 

Can you stop for a chat, or dwaddle?

 

If sitting is too high a risk and walking is an Acceptable or Tolerable risk, how was that difference in the likelihood of occupancy changing the risk from being Not Acceptable or Not Tolerable to Acceptable or Tolerable worked out?

 

Had the tree had a history of dropping limbs after bouts of hot dry weather, then given its location a risk-benefit assessment would've been necessary.  The risk would've needed to be managed by fencing off/mulching (people are reluctant to sit on mulch), or pruning, or felling.

 

<<I've witnessed SBD on 3 occasions, but I've never witnessed a failure due to decay first hand. Anecdotally that would suggest that if the risk of SBD is 'mind-bogglyingly low' then the risk of failure due to decay is... bamboozlingly low? I'm not sure what the technical term for this level of risk would be in the VALID system.>>

 

A quick point of clarification.  The risk from SBD is the likelihood of someone being there, the tree part falling, and then causing significant consequences.  Likelihood of failure is not the risk.

 

As for your experience.  The risks we're dealing with are so mind bogglingly low that none of our first-hand experiences, mine included, are likely to be representative of the underlying truth because of the small sample size.  What we do know (citations in the SBD Guide) is that of the 64 deaths over 10 years in the DARM database they put together for the National Tree Safety Group, none of them sounds like anything close to SBD.  Similarly, when the database for Australian trees deaths in coronial inquests since the 1870s is searched, and wind being a factor is filtered out, there's a similar magnitude of order lower than our base rate from ALL deaths by tree failure by x10 or so.

 

Again, familiarity with site history is important. Though you keep talking about how the risks are incredibly low, there WAS an incident at scone involving SBD. Trees throughout scone palace and the events field are now regularly surveyed by a very competent person. I don’t believe this sign was put up as an arboricultural recommendation but more reflects the anxieties of the property owners. Surely the fact that they are regularly surveyed over rules a sign asking people not to sit there? 

I’d say there’s a higher likelihood of occupancy between someone walking underneath it (which I believe most people don’t, as there’s a banking on the other side) and sitting, perhaps having a picnic beneath it (quite likely as it’s close to the outdoor seating from the cafe.
 

You seem very eager to criticise, which is easy when you’re spouting off on the internet as opposed to putting your name on a survey. 

Edited July 19, 2021 by Mr. Squirrel