Charette should be fun


The statue inside the cultural centre – apparently originally designed to be outside

I’ve been reading lots on council’s website tonight. Amazingly, lots of documents have appeared, even the radar report and the Public Voice transcript from December last year.

That was the meeting where two arborists, one an ex-councillor, Ian McKenzie, and the other Adrian Swain, appointed by council, talked about the trees and the risk they posed along with the benefits they provide.

I emailed a few councillors in December trying to get the transcript put on the website but was unsuccessful; one of them even asked council officers to do this but presumably had no luck; in fact, until some time in January the link to that meeting was completely wrong. Lucky I’m perfect is all I can say. (I wish.)

Its 15 pages  make interesting reading.

There was a site inspection of the trees before that council meeting (which was, not surprisingly, not well publicised)  and speaking about that Ian McKenzie says (the emphases are mine),

and these are the trees that failed, that were wind thrown. They started to fail and I don’t disagree that they needed to be removed, I don’t have a problem with that decision but there was not a catastrophic failure. There was warning, there were signs for people to see before that happened so [there] are other ways [to] address risk [such as] monitoring.

On page 4 he says in the context of things like cabling

‘There are arboricultural techniques and engineering techniques that can achieve outcomes if that’s what the community wants.

Speaking of the background to why so many people were upset by the process involved in this street tree issue he said

‘Oh, if I could just add very quickly one of the issues Mr Hewett [the now-retired council chief arborist] raised this afternoon was about the trust that the community had. This  [photo]was Tyrrell Street before the figs were removed from there and Council was told that it would get trees put back that would actually put a new canopy there. There it is today,there are trees there. They are Tuckeroos, they are not going to recreate the canopy that was there many years ago so that’s the concern the community often has. They are told one thing and in that case it hasn’t occurred.’

Adrian Swain, speaking as a consultant engaged by council, said,

‘Firstly may I say with regards to Ian’s comments, I am almost in complete agreeance with what he’s put forward this afternoon. Ithink he’s made some very good points and I think possibly from the point of view of Council, my understanding is that that’s a similar point of view that Council also [holds].’

On QTRA, the bane of our lives when it comes to trees, Mr McKenzie said,

‘QTRA is a relatively new methodology international but used in Australia and I think has been for 4 or 5 years now. I’ve had a good look at the QTRA report and it’s been modified from the basic methodology that we’re taught and some of that’s good, in fact I think the way that’s been developed has been quite good and I’ve done similar type of things myself in order to try and improve it.

I guess I have some concern about the probability of failure which is referred to in the report, it’s one of the three criteria that is used to come up with an index of 1 in 19.8, 1 in 20 when 1 in 10,000 is the benchmark and that is that the author uses the 2 trees that failed in one year, 2 trees out of 15 trees and comes up with a probability of a failure in a year and I think he says a year where there’s severe storms of 1 in 7½ and that’s the probability that he uses.

But when you’re using QTRA you’re looking at the probability in any year because when we don’t have June 2007’s every year, we could have one again next year, we may not have one for another 10 or 20 or 50 years but it’s not designed, it’s recognised that if you get severe enough storms trees will fall over and a lot of the trees that fell over in the June 2007 storms were not defective trees.

I went around and had a look at a lot of them, some were defective, others weren’t. Yes, you need to mitigate for that kind of risk but to take the worst case scenario and I believe that’s occurred in each of the two of the three criteria and the worst case scenario and then it’s been provided for the whole 14 trees rather than individual risk assessments of each tree so I’ve got some concerns about how that’s been worked.

However, having said that whilst I think 1 in 20 is an overstated level of risk I acknowledge fully that there is an issue of risk in those trees and I doubt whether it would come out and I’ve actually done a QTRA on a couple of them and it doesn’t come out as an acceptable level of risk. Mitigation is required though I don’t think it’s as serious as what that report may suggest.’

Former Post Office building

Some people in their vision to council suggested that the former Post Office building would make a good library or Art Gallery. It’s a lovely building that’s just rotting away.

Isn’t it so much better for everyone that the Federal Government would sell off a Victorian building to someone who doesn’t give a toss about it and instead use funny little plastic shopfronts like that on the right. What vision. What fiscally responsible behaviour.

Mr Swain when pressed by a councillor on whether he had found any errors in the report said,

There was a single error which I did [find]

It’s the third paragraph of section 7.4. It’s [an] error I believe but I stand corrected, where it references, it makes a statement that there’s no roots on the southern side of the southern trees and there’s no basis for that statement in the report. There may be as I know it, Dennis has a long history with the figs in this street and he may be privy to information that I’m not but in that report there’s no substantiation for that statement.

Another document provided is Adrian Swain’s QTRA review of the street and various reports.

In it he says’

The GPR Root Mapping Investigation Report attempts to ascertain the location of tree roots located within the Laman Street, Cooks Hill road reserve. Root investigations had previously been undertaken within the roadway, by excavating with an air knife under the supervision of arborist Dennis Marsden.

Unfortunately there is a distinct non – correlation with the data supplied when compared to the data collected during the previous root mapping investigations ie. the GPR report indicates that there are roots where previously it had been demonstrated they were not.

There is however a general lack of roots indicated within the roadway, rather a predominance of roots are indicated to be located within the pedestrian or footpath areas.

In December at Public Voice he had said,

‘I understand that Council has undertaken a process called ground penetrating radar and I think that was just done last week and hasn’t got results back yet. When it receives those results we’ll have a lot better idea about where those roots are.’

Later he says,

It has been noted that the data collected by the Ground Penetrating Radar does not correlate with actual root distribution as found when previously excavated. In approximately 85% of instances where trenches had been excavated the data does not correlate.The data does however indicate a predominance of roots within the pedestrian footpath areas. When combined with personal observations of the site, evidence provided of past root investigations and mapping undertaken with the use of an airknife excavation [sic]

In both reproductions of this report the sentence finishes at that point so I’m not sure what the conclusion was going to be. His references don’t help one work out the 85% figure: maybe we’ll get the chance to pick this apart at the charette. Is this 85% of trenchings vs radar all over the world or just in Laman Street? If radar is so unbelievable why did council spend the money on it in the first place? The only other council example I’ve read about was at Balmain Town Hall where radar investigations agreed with other tests but at this point without being an expert one is a bit lost – which helps council if what they want is to bamboozle both residents and elected officials alike.

I’ll try to be less wordy tomorrow. I find trying to pick QTRA apart fascinating but I may be alone in that. I’ve often wondered why my family’s eyes glaze over when I talk to them about this stuff…

A friend suggested a wonderful thing to me tonight. The trees in King Street that council ground to woodchip on the weekend showed us what Laman Street will be like if the trees do go there some time. There are people who find mature trees desirable: the Specimen Tree nursery examples of transplanting fully grown figs (see links) are fascinating. Even though arborists often don’t seem to like Hill’s figs there are probably places that would love to take these off our Phillistinic hands. Woodchipping them in comparison to giving them away would be awful.

An arborist sent me some information on the things one can do to encourage root growth in trees like these. I’ll try to post that tomorrow.

I did read something quickly in the paper today: the council employ an engagement officer who writes to defend the fact that all council are required to do is comply with the Local Government Act, presumably rather than – engage with the community.This was in the context of an apparent culture of secrecy in council…Maybe they could save some money and not bother with an engagement officer?       Home


Tags: , , , , , , , , , , ,

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: