Soil subsidence and trees

Ekka · 20th February 2007, 07:30 PM

Thanks to Royi Frame's thread I found the document he refered to.

Interesting to note that they used proper cutting techniques of reduction and thinning to see if there was a difference.

Also, what I have suspected all along, the trees regrew their removed volume quickly and in the case of reduction actually grew back more dense.

Thinning took the longest amount of time to return to pre pruning volumes.

Trees need to be reduced and have 70% to 90% of their foliage removed to make an impact on soil moisture content, then that has to be maintained.

Engineers reports here use the ht of a tree multiplied by a factor to determine the "safe" distance. In heavy clay the factor is 1 and in extreme cases 1.5

For example, 10m tall tree in highly reactive clay soil means 10mx1.5m= 15m away from building. I traced some of the engineers methodology back to a CSIRO document from 1985 called Division Building Research Sheet No. 10-75 Revised Sept 1985. How they get these numbers may be in the last document loaded, look around page 6 and 7.

Interesting info now added in post 60 about UK and new tree valuation methods and more stringent checking to prevent the loss of trees to subsidence claims

mdvaden · 1st April 2007, 04:37 AM

It would be interesting to see a report like that include factors such as different mulch depths, lawn ground cover, and different levels of irrigation.

It makes sense that thinning of a tree would have minimal effect.

I think it does reduce water use in one way, but it also opens the canopy to greater air movement, which I suspect would again increase water needs by a little bit.

Sean Freeman · 19th June 2007, 07:37 PM

Beginning of copied posts from Sudden Limb Failure risks and cases in the attached document a protected tree is removed due to house cracking, the judge gave the consent based on Dr Peter Mitchell's geotechnical advice.

You might recognise the names of the Arborist and the commisioner from Ekka's example....something of a back flip your honour? Courts can be treacherous places my friends.

Ekka · 19th June 2007, 08:05 PM

Well the Goode case was interesting as it came in at the subsidence angle, damage to property is what tilted the scales.

I always maintain that the right of way with trees is people and property.

With regard to the people angle they were concerned but borderline, then when the house was cracking and the soil expert concluded in his findings that trees were the major culprit the judge conceded.

An in Adelaide soil a 1m DBH and 20m tall euc will suck a lot of water out of the ground. However, in the first example I put up (1st post) the tree was retained and foundations altered to accommodate, so that guy is hanging around a while.

Interesting, I dont think root barrier would be effective at reducing subsidence anyway. The soil one side of the barrier would be contracting the other side expanding and the barrier would flex and move allowing soil movement.

Sean Freeman · 19th June 2007, 09:44 PM

Well, we're going to have to agree to disagree here since for me the ruling demonstrates one of the many issues that lead to trees being removed for no good reason. The commissioner back flips on the previous rulings he made with regards QTRA as an assessment system, he demonstartes a complete lack of understanding of the risk assessment process with regards trees generally and in relation to the mechanics of probalistic risk assessment specifically.

The evidence from Mr Nicolle is given greater creedence due to his PhD, and his being an acknowledged expert on Euc sps.

The PhD only demonstrates his ability to stay on at Uni for 10 or more years, problems with getting assignments completed on time me thinks.....as for the acknowledged expert status well cuts no ice with me since this expert still trots out the dog eared nonsense about certain species being prone to dropping limbs suddenly ie without cause or explaination...not an arguement I subscribe to at all.

The Goode decision is very dissapointing for a great number of reasons not least the above mentioned points, but also we get more unsubstantiated tripe about the role of one tree in the subsidence observed in adjacent buildings....wish I had a PhD or a doctorate degree maybe it would reduce the amount of evidence and support I have to provide for my limited specific conclusions in the reports I write week in and week out. Every situation is different, and demands the proper degree of examination before placing blame on the tree for subsidence, measuring relative soil moisture levels requires more than two or three test bores, even reactive clays are not all the same the nature of the chemical composition of the clay molecules plays a massive role in the way in which the clay responds to changing moisture levels, as does the physical structure of the soil its plasticity. I don't see anything in the court record that convinces me that Dr Mitchell's evidence outweighs Mr Nash's, except of course that the commisioner already seems to have made up his mind about the tree being the cause and the cracking bieng more than what you would expect to see in a house of that age on such soils tree or no tree.

The commissioner would do well to aquaint himself with this little known Arborist from the UK and maybe spend some of his not unsubstantial wage on the book and perhaps read it and learn something about the complexity in the relationship between vegetation and soil and moisture and subsidence.
http://www.willowmead.co.uk/

OK rant over.

Ekka · 19th June 2007, 10:51 PM

Can you put up explicitly where it's documented and proven that vegetation doesn't affect subsidence? In other words I'm looking for facts, we also have a thread on subsidence we could move these posts to.

I have been unable to prove what you are looking to prove. I draw your attention the extract below, this was given the weighting over the other guy.

Quote:

By comparison, Dr Mitchell is a specialist on the latter, having obtained a doctorate degree which involved an examination of the magnitude of soil moisture loss from the effect of trees, published a book which, inter alia, examined the role played by trees in causing soil change around footings, and having also published many papers on this topic. Dr Mitchell was the recipient of a Churchill Fellowship to study cracking in houses, and a major contributor to the development of an Australian Standard for the design of footings on expansive soil. Dr Mitchell advised the Court that, since commencing private practice in 1974, he had examined some 8,000 cracked houses, at least 6,000 of which had been affected by nearby trees.

Sean Freeman · 20th June 2007, 12:01 AM

My point is this mate, yes vegetation does have an effect....but what is it? how much wieght do you put on it and what are the specific elements of the specfic case in question?

Soils particularly clay soils react to relative moisture changes with and without the impact of vegetation. Evapotranspiration occus in all living vegetation plants move moisture from the soil but they can only do this to a certain extent....the chemical and physical nature of the soil also controls the movement of moisture up down and through the soil profile itself. The suction pressures in soil are measured in pF values, Southern and SouthWestern Australian soils studied by the Footings and Foundation Society of Victoria have been shown to retain or hold miosture at 7pF...the wilting point of native trees falls within the 3.5-4pF range these values are logarithmic, so in other words the trees cannot remove the last portion of soil moisture so critical to dramatic alterations in soil volume and compaction, other factors are at play.

It may be that in this case, the Goode case, that the tree was a major factor, but there is no evidence given to prove this...just comfy statements about the impressive resume of the expert..I would have been demanding that the expert show the evidence. As for the Australian standard for footings on expansive clay soils, would we be speaking of the same standard that talks of tree heights as an important factor in determining species suitability???

The experience documented by PG Biddle in his book "Tree root damage to buildings" of long term monitoring case studies over 20yrs after remedial work (often tree removals) for building subsidence has helped me to understand a little of the complexity that exists between soils, vegetation and the effects they can have on buildings. Hopefully such long term and balanced research will inform the changes to the UK building codes standards and regulations, and then we can wait for Oz to copy them....

I have read so much bunk written by so called experts on the ways trees are supposidly to blame without substantive evidence that I always want to see the evidence first, before the conclusion is made not the other way around.

Ekka · 20th June 2007, 09:29 AM

Boa, I still cant see any proof to the contrary just broad statements. Do you have the book and if so is there some data you can put up?

Sean Freeman · 20th June 2007, 07:13 PM

Yep got the book along with a great many others, where's your and others evidence to support broad statements that condemn trees with no substantive geotech investigation, no chemical analysis of soil type no level monitoring of both foundations and ground levels, no differentiation between tree species, evopotranspiration rates, foliar mass etc...etc.... The weight of eveidence should not be on those who want to retain healthy trees,but on those who want to remove them because their building has inadequate foundations.

Ekka · 20th June 2007, 07:46 PM

Problem is we're fighting an existing standard, you know that, so when you are up against that you need to prove the existing wrong as it is mandated correct by the system.

I had exactly this scenario recently with an engineers report.

I dont have the book and to date have not been able to get enough concrete evidence to turn that standard on it's ear although personally I do agree.

Sean Freeman · 20th June 2007, 08:52 PM

I know you feel the same way I do about this, and maybe this isn't the right spot for the debate, but what the heck since I'm typing and its a bit of a hobby horse for me....the standard is based on a very poor understanding of the biology of trees, and specifically the action and impact of root, it is based almost slavishly on the British standard which has the same idiotic base line of 1.5 x the height of the tree as the preferred distance for trees from building foundations.

We have a professional soil engineers and geotechs who make a very good living out of investigations and reports on the nature of soils in any particular area, where buidlings already exist or where buildings are planned to be built. Now to this fine body of men and women trees seem to be a total anathema, the existing standard along with local and state building regs don't help so instead of gradually getting more trees (properly) retained on new sites, and existing trees (properly) managed on existing sites we still seem to be in the trap of painting trees as the bad guys.

Trees can and do move vast amounts of water in the soil every day, but we need to recognise that movement is not simply one way (evapotranspiration) trees also lift vast quantities of water from lower in the soil profile to upper protions of the profile. Moisture gradients in the soil also lead to changes in localised moisture content....drying soils pull moisture from adjacent areas with greater moisture in other words..without the help of any vegetation.

The impact of altered relative moisture levels in a volume of soil is dependant on numerous factors previously mentioned in this thread,....and the impact that these soil changes have on buildings is also dependant on the nature of the civil works undertaken during intial subdivision and the foundations for that building.

So what am I getting at? The Goode ruling based on the evidence from the transcript is bad in so many ways, it reflects some of the fundemental misunderstandings that persist about tree roots and building movements. I'm not saying trees are never a major cause of soil volume alterations and resultant building damage...that would be silly...however I do understand enough about soil physics and chemistry to know that this simplistic model that underlies the current standards is shifting both the blame and the responsibility for subsidence from the people who alter the structure of the soil profile so fundamentally to trees that more often than not were there long before bulding on the site was even considered.

Good quality, properly installed moisture barriers (note not root barriers) have a real role in this area I think. Surround the foundations of a building by such barriers to a depth 1-2m below the excavation depth and you will effectively isolate the sub soil profile from aterations in relative moisture levels. The impact of the original cut and/or fill process and the thermal mass fluctuations created by the building will have an impact on the soil and its volume and therefore over time there will still be some buildings that still have cracking, and shortened service life span as a result.....some experts would still blame the tree 15m away in the neighbours yard for that, and if you had the same commissioner as the Goode case residing well bad luck tree.....

Ekka · 20th June 2007, 09:10 PM

I personally feel that by going the direction of cracks/subsidence/soil moisture many a tree can be condemned easily by the current standard.

From that one I had it was a regimented cemented standard.

For us as arborists to contest it we'd need mountains of hard core proof and cases. I did find a South Australian 2 year test case where meters were used in a number of locations to measure the differences around trees etc ... but for some crazy reason they used sapling trees, I mean 6' tall whip sticks only a few years old which were new street plantings.

That one concluded no influence but made a special point that the trees were small and immature, so why bloody bother!

We have done volumes of work where due to engineers reports on cracked houses they have underpinned and recommended removal of all trees within 6m of the building, no BS! Try argue with that hard core profession, also then you are in breach of a standard ...

... like some-one saying AS4373 is completely incorrect and topping is better than target cutting as the tree retains more biomass (stored sugars), replaces removed foliage, auto mulches if breakouts occur and creates habitat if decay sets in. In the natural course of tree management in the bush nature actually works better than AS4373 and this can be clearly witnessed when you consistently see the heads of the taller trees blow out.

Sean Freeman · 20th June 2007, 09:32 PM

If it comes down to an instance where you have a tree or trees that you or your client cares greatly for and the tree/s being threatened by the application of this one size fits all approach then you don't have to challenge the standard you merely have to demand that the evidence is provided. I have yet to encounter a geotech report or soil enginerring report that
1) fits the description of an adequate scientific investigation and written report
2) contains clear unequivical evidence of a tree/s being the single major factor in the building cracking/subsidence.

Now that could be due to the poor standard of reports here in Qld, how they get the money they do get for the rubbish they pass off as scientific reports is beyond me...but thats a different matter

The reports I've seen don't have enough test bores to determine the relative moisture levels across the span of the built structure and the suspect vegetation, well expensive stuff drilling holes eh!!
They don't determine the exact nature of the soil, often I suspect they pull soil type from past geotech surveys done when the particular area was being subdivided.
They don't determine what excavations (cut and fill) were done prior to the building being constructed.
They don't examine/assess the effect the original soil alterations would have had and are continuing to have (differential settlement under foundations increases over time)
They don't deteremine the suction capacity of the soil...and can't since they haven't determined the exact soil type!!
Soil plasticity is rarely mentioned, construction plans and specs are rarely referred to.

So I wouldn't bash my head on their stupid wall, but ratther lead them to the wall and invite them to make a start themselves...

As consultants we constantly have to meet minimum standards in the assessments we make and the reports we write, I expect other professions to at least meet the same performance levels.

If the LGA and the regional/state development courts are making rulings like the Goode one then we do have a hard road to walk no doubt about it, but it doesn't mean we should throw in the towel rather better arm yourself with as much info and research and understanding and challenge the inadequacies when you find them.

As I said before the tree/s may be part of the problem but unless they are almost against the building (and assuming they are healthy) removal is hardly the best solution for our communities given all we know about our environmental state of affairs.

Ekka · 20th June 2007, 09:36 PM

Hahaha Boa, you make me laugh.

That was about as precise as the geo report got too! But all trees were condemned.

I'll get you involved with the next case should I decide to take it on, I know one thing, it's a bloody lot harder to dig or do anything around palm roots than where there's no roots, so some sort of impact/deflection test is req'd too.

Bernard Keays · 22nd June 2007, 10:58 PM

EkkA/Boa ... somewhere in your discussion you mentioned 'moisture barrier (not root barrier)'. I've heard of root barrier, used mostly 450mm but have Engineer reports stipulating 950mm around buildings. What do mean by moisture barrier?

Sean Freeman · 22nd June 2007, 11:28 PM

Hi Bernard, its the same animal just the emphasis is changed...instead of seeing it as a barrier to the growth of roots surrounding the tree, I see it and try to convince the client to see it as a barrier to the alteration of moisture levels in the sub soil around and under the foundations of their buildings..surrounding the building isolating it from the various natural cycles (water included) going on around their building.

Note though that a barrier installed to achieve this end result is much deeper than any root barrier...and as was mentioned over and over there is no one fix all solution to such a varied and often complicated range of factors leading to subsidence.

End of copied posts from Sudden Limb Failure risks and cases

Ekka · 22nd July 2007, 10:37 AM

BTF 18 is a CSIRO document pertaining to foundation issues and covers trees.

It can be purchased for a few bucks here, also CSIRO publishes many great fact based books etc.

http://publish.csiro.au/pid/3612.htm

Also I have loaded up a South Australian trial of where they tried to monitor trees and their influence on subsidence however they did choose juvenile trees which didn't really make the project so worth while.

However, it does go through the steps. Which means we, as arborists, may be able to replicate or try to gather some data into mature trees influence on soil moisture/subsidence.

If the Goode case is anything to go by then we need to become more proactive to eliminate the wholesale slaughter of trees due to possibility they might cause subsidence.

Current Australian standards suggest that the height of the tree is the distance it must be away from the house. That makes many trees in the urban setting a target, especially when houses are cracking anyway due to drought.

There are remedies, they suggest metal or concrete barrier, most likely as a poly sheet would be too flexible and if the soil on the tree side shrunk the barrier would bow and allow soil on the other side to move.

Sean Freeman · 22nd July 2007, 12:52 PM

Yes you are right Ekka, it was a shame that the SA study focussed on such young trees, but it kind of relates to what we were talking about yesterday each study no matter how carefully designed will be of limited use in a real situation with say a healthy mature gum tree 40m+ tall in an urban sudivision built on clay soils, being accused of causing subsidence to three or more private houses.

The variables envolved in the relationship between vegetation relative soil moisture levels and the physics of a particular volume of soil; its shrinkage, swelling, and load bearing capacity are not agreed upon.

For me personally every time I get asked to visit a building with visible cracking in it possibly caused by the evapotranspiration of adjacent vegetation I get more and more frustrated. Noone is willing to spend the money to undertake the proper geotech investigation to get anything like enough data on which to base an assessment. We are constantly left with engineers and building inspectors making sweeping statements about this or that tree species being notorious for such damage, and as Ekka points out having the Standard to fall back on, a standard based on height of the tree!!!

As I'm sure all of you have noticed I'm a tree hugger

and always begin from the starting point of defending the tree, I am not however blind to the reality that trees as with all vegetation have a big role in altering relative soil moisture levels, but without understanding hat else is going on you are no better placed then someone stating that fungi are bad for trees.

We as Arborists often seem to be excluded from influencing the critical concept stages of urban subdivision, when nearly all of the problems including trees being accused of subsidence could be avoided.

I thought I had posted this before but reading back through couldn't find it so apologies if you've seen it before, its from about 7yrs ago and by Bob Wulkowicz.

Rehydration.doc

Also reading back over the previous posts in this thread it seems like I'm suggesting that PG Biddle the author of Trees and Subsidence is arguing my point for me, well that is not true his book has more examples of trees being linked to building subsidence than not....but my use of his book as reference relates to the fact that he does have examples of trees being wrongly accused of building damage, being removed then his long term (10yr+) detail monitoring proving that the tree was not the principal factor...ie the subsidence and building movement is a not abated!

Anyway I strongly suggest that anyone who can afford it buy both his books and increase their own knowledge and understanding of the processes at work in the soils around and under our built infrastructure, and how trees fit into that interaction. http://www.willowmead.co.uk/

Ekka · 22nd July 2007, 03:25 PM

OK, I just went and did some investigative work.

These gums were cut down recently at Chatswood Primary School in Springwood. They were in the carpark close to the back fence.

I large grey gum stayed as was agreed koala habitat.

Reason for the removals was the houses were subsiding. Engineers reports identified trees as contributing factor and ironically houses subsided closer to where trees were.

There were multiple test holes for soil analysis, highly reactive clay. Standards were called up to identify the trees as contributing.

Education minister was sent a letter and then a meeting was arranged with all parties, school principal, council arborists, Q-build etc. Trees were removed and the remaining tree will have to have a barrier installed.

This is a typical scenario. The corner of the house on the right subsided 140mm. In a less costly alternative to underpinning the area was injected with pressurized styrenefoam which corrected the bulk of it. No movement since so repairs to the brick work can commence.

The other neighbour had apparently complained for many years about the trees but no action was taken by any parties, it took the new neighbour (been there 2 years) to get engineers reports and take the matter on.

Had the correct course of action (engineers report) been taken in early instance there would have been a portion of liability and cost to the tree owners (govt school).

Sean Freeman · 22nd July 2007, 03:46 PM

Be very interested to know how old the trees were, and how old the houses affected were...ie when where they built....what type of foundation slab was laid and over what sub-base.

On truely reactive soils the only long term foundations I know of are slabs with reinforced stiffened beams across the span every 4/5m or waffle slabs with the floor slab placed on top...both are more expensive and take longer to prepare and lay than simple floating raft slabs. Consequently they don't get built very often. I have the distinct feeling that what was done even 10yrs ago will not last on top of reactive soils for another 10yrs...even if you could claim 50yrs life span for a concrete and block construction seems insignificant compared to the most moderate estimates of the life span of a healthy gum tree, something amiss there imo.

Constructing a moisture barrier around the foundation whatever its quality would definately give greater protection than any post construction attempt to rectify subsidence...but again that would cost, and developers and builders are all for keeping the costs down for the potential home owner

Ekka · 22nd July 2007, 04:43 PM

AS 2870-1996 is the standard for foundations but anything built before hand ... bad luck! I suppose you rely on the builder doing the right thing.

Appears from this document that 300mm dia piers at approx 2m intervals are sunk to a more solid sub-base. http://www.bsa.qld.gov.au/NR/rdonlyr...encePolicy.pdf

Now, I've been driving past new sites where they like to retain the odd gum tree and build like 2m away from it, so I wonder if the builders are doing the right thing. You'd have to be there when they pour the slab to know what sort of additional protection you got coz of the tree.

Maybe we can ask a builder/geo-engineer to comment here? Who do you know?

Sean Freeman · 22nd July 2007, 04:49 PM

I've got to visit quite a large profile development site tomorrow I'll talk to the site managers and see what info I can glean from them, meantime I'll email you a couple of pdf's too big to post so you can see just how much tech analysis is supposed to go on even before any soil is disturbed...as you say makes you wonder when we visit some of the development sites up and down the state just how much unsupported box ticking is going on.

Sean Freeman · 22nd July 2007, 05:42 PM

Here's a pdf that gives us something of an insight into the problems and complexities that exist between geotechs, struct engineers, architects, and builders...oh yes and the home owner! Not solely pertaining to the issue at hand, trees but very informative non the less..the better we understand their world and their concerns the better we can help them to improve the management of trees in this messy web of interactions!

Pitfalls_Risks.pdf

Ekka · 23rd July 2007, 08:48 PM

Here's a real live case.

I worked this house back in 2005 when the underpinning was going on. Revisited today to do more work.

I'll show a bunch of pics first and I got hold of the entire geotech report, the whole shebang!

To start with to liven this thread up I'll insert the pics. The customer was great today, gave me the pics and I scanned them, loaded brush and fed me!

He was very willing to help and said if this saved anyone from the stress and the hostilities from neibs it would be great.

Yes, you tend to forget how you would feel having to shell out $10k+ and your neighbour refuses to co-operate. The tree mysteriously died during the process and the owner of the tree had it cut down after it was dead, but threatened my customer with legal action. Oh yes, the tree owners house was also cracked.

This is the view from the front yard 2002 showing the tree on the left marked.

And this is the few from the back yard, tree on the right.

This pic shows the gum tree root under the slab. This was the 4th pit for underpinning inside the back garage. The water is from the concrete saw.

What the process was .... the builder had to manually dig (jackhammer spade and bucket) a small pit down till he hit solid ground at around 2m in this case. Then they dig under the foundation and "fishtale" the pit. Yes, he physically climb into that small hole and digs, fills a bucket and another guy hauls it up. Fill it with reinforced concrete (approx 1.5m3 into each hole) to around 300mm short of the house slab.

The builder uses 120 tonne hydraulic jack with steel plate above and below jack to raise the house (lots of creaking of masonary going on), once ht is achieved etc steel braces are inserted between the pit concrete and house slab, jack is removed and the whole lot filled with concrete.

This pic shows the 120t jack in the gap.

Ekka · 23rd July 2007, 09:18 PM

I also have information regarding appropriate root barrier.

Partly in the document attached which I scanned from the report and converted to PDF pic files. It's 6.57mb in size, I cannot find the document on CSIRO's website.

In addition (from the geotech report) states the trench should be 100mm wide and 2m deep, filled with concrete with a maximum aggregate size 10mm strength 15mPa, preferably at least 2m away from house foundation.

As I thought earlier, a simple typical plastic root barrier sheet wouldn't suffice as it will bend if soil wants to move. So to construct barriers like this is expensive and means you'll have to get a trencher or backhoe in. In effect the barrier is some sort of subterranean retaining wall in addition to root stopper.

Document also has a list of bad tree species.

http://www.treeworld.info/manualuplo...oundations.pdf

Oldtimer · 24th July 2007, 05:09 AM

There is a whole industry in the US dedicated to the "leveling " of house foundations. Some of the houses were built on very plastic clay soils with high shrink and swell capacity due to seasonal variation in the amount of moisture on the soil. So foundation cracks or the walls cracks on the house are common. My house is in a subdivision with caves all over, there are many houses that show the signs. Also, There is one that has a tree actually touching the foundation of the garage and there is no obvious indication of damage. ( the tree is Soooo close to the house that they actually cut a small portion ( about 2 ft by long by 1 ft wide) of the roof overhang to allow the tree to pass thru it. ( I will take a photo later for you to see it).
Those cracks on the photo that Ekka posted are nothing compared to some of the nasty ones we regularly see around here. They have a pier system that they pressure inject below the foundations to repair some of the damage but most of the soils around here are marginal for the type of construction used by local builders. Good topic!

Roller · 9th September 2007, 10:10 PM

building+clay soil+tree+fell.....!!

Ekka · 9th September 2007, 10:26 PM

Roller

This is big business in UK, I see many consultants offering services for trees in proximity to houses, subsidence etc. Some offer to gather evidence to remove liability for tree owners whilst others the opposite.

If you have any reference material it would be great.

Roller · 10th September 2007, 12:28 AM

UK Law Case Summary

Delaware Mansions Ltd and another v. Westminster City Council.
Court of Appeal, July 1999. Beldam, Thorpe and Pill LJJ.
This case involved damage to a property by tree roots.
In 1989 structural engineers reported that damage had occurred to some blocks of flats and that a Plane tree, which was owned by Westminster City Council, was responsible for the damage. The engineers recommended underpinning of the flats or removal of the tree. The council refused to remove the tree.

The flats were sold in June 1990 to the second appellant company for one pound. The first appellant company was formed, and owned, by the tenants to provide maintenance and service to the flats.

These companies were seeking damages from Westminster City Council for the cost of the remedial works carried out to repair the foundations of the flats, and which cost some ?570,735 pounds. However, their claim was dismissed on the grounds that they could not claim for the damages because the damage had occurred before they had become the new owners of the flats.

The plaintiffs appealed and won. During his judgement, Pill LJ said

"Thus, where there is a continuing nuisance, the owner is entitled to a declaration, to abate the nuisance, to damages for physical injury and to an injunction".

And,

"If the council had agreed to remove the tree when asked, the damages would have been very small. In the circumstances, which are probably unusual, the fact that the nuisance existed before the second appellant became the owner is irrelevant".

Ekka · 10th September 2007, 07:37 AM

And hence it should be.

Frankly, if something in your property does damage to mine, then you pay.

Fair and simple.

You want a tree, then ensure it does not trespass either above or below the ground.

Installation of an adequate root barrier would also have prevented the problem. If the tree owner thinks it unreasonable to fork out say $10,000 for an engineered suitable concrete permanent root barrier then how could they consider it fair and reasonable for the victim to fork out much more than that?

Thanks Roller

19th June 2007, 08:05 PM	#4
Ekka Admin - Dip Arb & Hort & Seldom Wrong Join Date: Jan 2007 Location: Brisbane Posts: 9,772	Well the Goode case was interesting as it came in at the subsidence angle, damage to property is what tilted the scales. I always maintain that the right of way with trees is people and property. With regard to the people angle they were concerned but borderline, then when the house was cracking and the soil expert concluded in his findings that trees were the major culprit the judge conceded. An in Adelaide soil a 1m DBH and 20m tall euc will suck a lot of water out of the ground. However, in the first example I put up (1st post) the tree was retained and foundations altered to accommodate, so that guy is hanging around a while. Interesting, I dont think root barrier would be effective at reducing subsidence anyway. The soil one side of the barrier would be contracting the other side expanding and the barrier would flex and move allowing soil movement. __________________ TAS Training & Assessment Services\| Arb and Hort Training available here Free Online Tree Value Calculator by TreeWorld Free Online TPZ and SRZ AS4970-2009 Calculator by TreeWorld Free Online Tree Surface Area and Tree Volume Calculator by TreeWorld Free Tree and Green Industry Deep Link Directory ... Yes, I also SEO (Optimize) and build websites that fly high in Google Qualified Brisbane Tree Lopping \| Stump Grinding Brisbane Brisbane - Gold Coast Consulting Arborist, Tree and Arborist Reports \| Project Arborist

19th June 2007, 09:44 PM	#5
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	Well, we're going to have to agree to disagree here since for me the ruling demonstrates one of the many issues that lead to trees being removed for no good reason. The commissioner back flips on the previous rulings he made with regards QTRA as an assessment system, he demonstartes a complete lack of understanding of the risk assessment process with regards trees generally and in relation to the mechanics of probalistic risk assessment specifically. The evidence from Mr Nicolle is given greater creedence due to his PhD, and his being an acknowledged expert on Euc sps. The PhD only demonstrates his ability to stay on at Uni for 10 or more years, problems with getting assignments completed on time me thinks.....as for the acknowledged expert status well cuts no ice with me since this expert still trots out the dog eared nonsense about certain species being prone to dropping limbs suddenly ie without cause or explaination...not an arguement I subscribe to at all. The Goode decision is very dissapointing for a great number of reasons not least the above mentioned points, but also we get more unsubstantiated tripe about the role of one tree in the subsidence observed in adjacent buildings....wish I had a PhD or a doctorate degree maybe it would reduce the amount of evidence and support I have to provide for my limited specific conclusions in the reports I write week in and week out. Every situation is different, and demands the proper degree of examination before placing blame on the tree for subsidence, measuring relative soil moisture levels requires more than two or three test bores, even reactive clays are not all the same the nature of the chemical composition of the clay molecules plays a massive role in the way in which the clay responds to changing moisture levels, as does the physical structure of the soil its plasticity. I don't see anything in the court record that convinces me that Dr Mitchell's evidence outweighs Mr Nash's, except of course that the commisioner already seems to have made up his mind about the tree being the cause and the cracking bieng more than what you would expect to see in a house of that age on such soils tree or no tree. The commissioner would do well to aquaint himself with this little known Arborist from the UK and maybe spend some of his not unsubstantial wage on the book and perhaps read it and learn something about the complexity in the relationship between vegetation and soil and moisture and subsidence. http://www.willowmead.co.uk/ OK rant over. __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup

20th June 2007, 12:01 AM	#7
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	My point is this mate, yes vegetation does have an effect....but what is it? how much wieght do you put on it and what are the specific elements of the specfic case in question? Soils particularly clay soils react to relative moisture changes with and without the impact of vegetation. Evapotranspiration occus in all living vegetation plants move moisture from the soil but they can only do this to a certain extent....the chemical and physical nature of the soil also controls the movement of moisture up down and through the soil profile itself. The suction pressures in soil are measured in pF values, Southern and SouthWestern Australian soils studied by the Footings and Foundation Society of Victoria have been shown to retain or hold miosture at 7pF...the wilting point of native trees falls within the 3.5-4pF range these values are logarithmic, so in other words the trees cannot remove the last portion of soil moisture so critical to dramatic alterations in soil volume and compaction, other factors are at play. It may be that in this case, the Goode case, that the tree was a major factor, but there is no evidence given to prove this...just comfy statements about the impressive resume of the expert..I would have been demanding that the expert show the evidence. As for the Australian standard for footings on expansive clay soils, would we be speaking of the same standard that talks of tree heights as an important factor in determining species suitability??? The experience documented by PG Biddle in his book "Tree root damage to buildings" of long term monitoring case studies over 20yrs after remedial work (often tree removals) for building subsidence has helped me to understand a little of the complexity that exists between soils, vegetation and the effects they can have on buildings. Hopefully such long term and balanced research will inform the changes to the UK building codes standards and regulations, and then we can wait for Oz to copy them.... I have read so much bunk written by so called experts on the ways trees are supposidly to blame without substantive evidence that I always want to see the evidence first, before the conclusion is made not the other way around. __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup

20th June 2007, 09:29 AM	#8
Ekka Admin - Dip Arb & Hort & Seldom Wrong Join Date: Jan 2007 Location: Brisbane Posts: 9,772	Boa, I still cant see any proof to the contrary just broad statements. Do you have the book and if so is there some data you can put up? __________________ TAS Training & Assessment Services\| Arb and Hort Training available here Free Online Tree Value Calculator by TreeWorld Free Online TPZ and SRZ AS4970-2009 Calculator by TreeWorld Free Online Tree Surface Area and Tree Volume Calculator by TreeWorld Free Tree and Green Industry Deep Link Directory ... Yes, I also SEO (Optimize) and build websites that fly high in Google Qualified Brisbane Tree Lopping \| Stump Grinding Brisbane Brisbane - Gold Coast Consulting Arborist, Tree and Arborist Reports \| Project Arborist

20th June 2007, 07:13 PM	#9
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	Yep got the book along with a great many others, where's your and others evidence to support broad statements that condemn trees with no substantive geotech investigation, no chemical analysis of soil type no level monitoring of both foundations and ground levels, no differentiation between tree species, evopotranspiration rates, foliar mass etc...etc.... The weight of eveidence should not be on those who want to retain healthy trees,but on those who want to remove them because their building has inadequate foundations. __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup

1st April 2007, 04:37 AM	#2
mdvaden Former Member Join Date: Feb 2007 Location: Oregon Posts: 412	It would be interesting to see a report like that include factors such as different mulch depths, lawn ground cover, and different levels of irrigation. It makes sense that thinning of a tree would have minimal effect. I think it does reduce water use in one way, but it also opens the canopy to greater air movement, which I suspect would again increase water needs by a little bit.

20th June 2007, 07:46 PM	#10
Ekka Admin - Dip Arb & Hort & Seldom Wrong Join Date: Jan 2007 Location: Brisbane Posts: 9,772	Problem is we're fighting an existing standard, you know that, so when you are up against that you need to prove the existing wrong as it is mandated correct by the system. I had exactly this scenario recently with an engineers report. I dont have the book and to date have not been able to get enough concrete evidence to turn that standard on it's ear although personally I do agree. __________________ TAS Training & Assessment Services\| Arb and Hort Training available here Free Online Tree Value Calculator by TreeWorld Free Online TPZ and SRZ AS4970-2009 Calculator by TreeWorld Free Online Tree Surface Area and Tree Volume Calculator by TreeWorld Free Tree and Green Industry Deep Link Directory ... Yes, I also SEO (Optimize) and build websites that fly high in Google Qualified Brisbane Tree Lopping \| Stump Grinding Brisbane Brisbane - Gold Coast Consulting Arborist, Tree and Arborist Reports \| Project Arborist

20th June 2007, 08:52 PM	#11
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	I know you feel the same way I do about this, and maybe this isn't the right spot for the debate, but what the heck since I'm typing and its a bit of a hobby horse for me....the standard is based on a very poor understanding of the biology of trees, and specifically the action and impact of root, it is based almost slavishly on the British standard which has the same idiotic base line of 1.5 x the height of the tree as the preferred distance for trees from building foundations. We have a professional soil engineers and geotechs who make a very good living out of investigations and reports on the nature of soils in any particular area, where buidlings already exist or where buildings are planned to be built. Now to this fine body of men and women trees seem to be a total anathema, the existing standard along with local and state building regs don't help so instead of gradually getting more trees (properly) retained on new sites, and existing trees (properly) managed on existing sites we still seem to be in the trap of painting trees as the bad guys. Trees can and do move vast amounts of water in the soil every day, but we need to recognise that movement is not simply one way (evapotranspiration) trees also lift vast quantities of water from lower in the soil profile to upper protions of the profile. Moisture gradients in the soil also lead to changes in localised moisture content....drying soils pull moisture from adjacent areas with greater moisture in other words..without the help of any vegetation. The impact of altered relative moisture levels in a volume of soil is dependant on numerous factors previously mentioned in this thread,....and the impact that these soil changes have on buildings is also dependant on the nature of the civil works undertaken during intial subdivision and the foundations for that building. So what am I getting at? The Goode ruling based on the evidence from the transcript is bad in so many ways, it reflects some of the fundemental misunderstandings that persist about tree roots and building movements. I'm not saying trees are never a major cause of soil volume alterations and resultant building damage...that would be silly...however I do understand enough about soil physics and chemistry to know that this simplistic model that underlies the current standards is shifting both the blame and the responsibility for subsidence from the people who alter the structure of the soil profile so fundamentally to trees that more often than not were there long before bulding on the site was even considered. Good quality, properly installed moisture barriers (note not root barriers) have a real role in this area I think. Surround the foundations of a building by such barriers to a depth 1-2m below the excavation depth and you will effectively isolate the sub soil profile from aterations in relative moisture levels. The impact of the original cut and/or fill process and the thermal mass fluctuations created by the building will have an impact on the soil and its volume and therefore over time there will still be some buildings that still have cracking, and shortened service life span as a result.....some experts would still blame the tree 15m away in the neighbours yard for that, and if you had the same commissioner as the Goode case residing well bad luck tree..... __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup

20th June 2007, 09:10 PM	#12
Ekka Admin - Dip Arb & Hort & Seldom Wrong Join Date: Jan 2007 Location: Brisbane Posts: 9,772	I personally feel that by going the direction of cracks/subsidence/soil moisture many a tree can be condemned easily by the current standard. From that one I had it was a regimented cemented standard. For us as arborists to contest it we'd need mountains of hard core proof and cases. I did find a South Australian 2 year test case where meters were used in a number of locations to measure the differences around trees etc ... but for some crazy reason they used sapling trees, I mean 6' tall whip sticks only a few years old which were new street plantings. That one concluded no influence but made a special point that the trees were small and immature, so why bloody bother! We have done volumes of work where due to engineers reports on cracked houses they have underpinned and recommended removal of all trees within 6m of the building, no BS! Try argue with that hard core profession, also then you are in breach of a standard ... ... like some-one saying AS4373 is completely incorrect and topping is better than target cutting as the tree retains more biomass (stored sugars), replaces removed foliage, auto mulches if breakouts occur and creates habitat if decay sets in. In the natural course of tree management in the bush nature actually works better than AS4373 and this can be clearly witnessed when you consistently see the heads of the taller trees blow out. __________________ TAS Training & Assessment Services\| Arb and Hort Training available here Free Online Tree Value Calculator by TreeWorld Free Online TPZ and SRZ AS4970-2009 Calculator by TreeWorld Free Online Tree Surface Area and Tree Volume Calculator by TreeWorld Free Tree and Green Industry Deep Link Directory ... Yes, I also SEO (Optimize) and build websites that fly high in Google Qualified Brisbane Tree Lopping \| Stump Grinding Brisbane Brisbane - Gold Coast Consulting Arborist, Tree and Arborist Reports \| Project Arborist

20th June 2007, 09:32 PM	#13
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	If it comes down to an instance where you have a tree or trees that you or your client cares greatly for and the tree/s being threatened by the application of this one size fits all approach then you don't have to challenge the standard you merely have to demand that the evidence is provided. I have yet to encounter a geotech report or soil enginerring report that 1) fits the description of an adequate scientific investigation and written report 2) contains clear unequivical evidence of a tree/s being the single major factor in the building cracking/subsidence. Now that could be due to the poor standard of reports here in Qld, how they get the money they do get for the rubbish they pass off as scientific reports is beyond me...but thats a different matter The reports I've seen don't have enough test bores to determine the relative moisture levels across the span of the built structure and the suspect vegetation, well expensive stuff drilling holes eh!! They don't determine the exact nature of the soil, often I suspect they pull soil type from past geotech surveys done when the particular area was being subdivided. They don't determine what excavations (cut and fill) were done prior to the building being constructed. They don't examine/assess the effect the original soil alterations would have had and are continuing to have (differential settlement under foundations increases over time) They don't deteremine the suction capacity of the soil...and can't since they haven't determined the exact soil type!! Soil plasticity is rarely mentioned, construction plans and specs are rarely referred to. So I wouldn't bash my head on their stupid wall, but ratther lead them to the wall and invite them to make a start themselves... As consultants we constantly have to meet minimum standards in the assessments we make and the reports we write, I expect other professions to at least meet the same performance levels. If the LGA and the regional/state development courts are making rulings like the Goode one then we do have a hard road to walk no doubt about it, but it doesn't mean we should throw in the towel rather better arm yourself with as much info and research and understanding and challenge the inadequacies when you find them. As I said before the tree/s may be part of the problem but unless they are almost against the building (and assuming they are healthy) removal is hardly the best solution for our communities given all we know about our environmental state of affairs. __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup

20th June 2007, 09:36 PM	#14
Ekka Admin - Dip Arb & Hort & Seldom Wrong Join Date: Jan 2007 Location: Brisbane Posts: 9,772	Hahaha Boa, you make me laugh. That was about as precise as the geo report got too! But all trees were condemned. I'll get you involved with the next case should I decide to take it on, I know one thing, it's a bloody lot harder to dig or do anything around palm roots than where there's no roots, so some sort of impact/deflection test is req'd too. __________________ TAS Training & Assessment Services\| Arb and Hort Training available here Free Online Tree Value Calculator by TreeWorld Free Online TPZ and SRZ AS4970-2009 Calculator by TreeWorld Free Online Tree Surface Area and Tree Volume Calculator by TreeWorld Free Tree and Green Industry Deep Link Directory ... Yes, I also SEO (Optimize) and build websites that fly high in Google Qualified Brisbane Tree Lopping \| Stump Grinding Brisbane Brisbane - Gold Coast Consulting Arborist, Tree and Arborist Reports \| Project Arborist

22nd June 2007, 10:58 PM	#15
Bernard Keays Semi-mature vigorous tree Join Date: Jun 2007 Location: Glasshouse Posts: 194	EkkA/Boa ... somewhere in your discussion you mentioned 'moisture barrier (not root barrier)'. I've heard of root barrier, used mostly 450mm but have Engineer reports stipulating 950mm around buildings. What do mean by moisture barrier?

22nd June 2007, 11:28 PM	#16
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	Hi Bernard, its the same animal just the emphasis is changed...instead of seeing it as a barrier to the growth of roots surrounding the tree, I see it and try to convince the client to see it as a barrier to the alteration of moisture levels in the sub soil around and under the foundations of their buildings..surrounding the building isolating it from the various natural cycles (water included) going on around their building. Note though that a barrier installed to achieve this end result is much deeper than any root barrier...and as was mentioned over and over there is no one fix all solution to such a varied and often complicated range of factors leading to subsidence. End of copied posts from Sudden Limb Failure risks and cases __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup Last edited by Ekka; 22nd July 2007 at 10:22 AM. Reason: put in end marker of copied posts

22nd July 2007, 12:52 PM	#18
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	Yes you are right Ekka, it was a shame that the SA study focussed on such young trees, but it kind of relates to what we were talking about yesterday each study no matter how carefully designed will be of limited use in a real situation with say a healthy mature gum tree 40m+ tall in an urban sudivision built on clay soils, being accused of causing subsidence to three or more private houses. The variables envolved in the relationship between vegetation relative soil moisture levels and the physics of a particular volume of soil; its shrinkage, swelling, and load bearing capacity are not agreed upon. For me personally every time I get asked to visit a building with visible cracking in it possibly caused by the evapotranspiration of adjacent vegetation I get more and more frustrated. Noone is willing to spend the money to undertake the proper geotech investigation to get anything like enough data on which to base an assessment. We are constantly left with engineers and building inspectors making sweeping statements about this or that tree species being notorious for such damage, and as Ekka points out having the Standard to fall back on, a standard based on height of the tree!!! As I'm sure all of you have noticed I'm a tree hugger and always begin from the starting point of defending the tree, I am not however blind to the reality that trees as with all vegetation have a big role in altering relative soil moisture levels, but without understanding hat else is going on you are no better placed then someone stating that fungi are bad for trees. We as Arborists often seem to be excluded from influencing the critical concept stages of urban subdivision, when nearly all of the problems including trees being accused of subsidence could be avoided. I thought I had posted this before but reading back through couldn't find it so apologies if you've seen it before, its from about 7yrs ago and by Bob Wulkowicz. Rehydration.doc Also reading back over the previous posts in this thread it seems like I'm suggesting that PG Biddle the author of Trees and Subsidence is arguing my point for me, well that is not true his book has more examples of trees being linked to building subsidence than not....but my use of his book as reference relates to the fact that he does have examples of trees being wrongly accused of building damage, being removed then his long term (10yr+) detail monitoring proving that the tree was not the principal factor...ie the subsidence and building movement is a not abated! Anyway I strongly suggest that anyone who can afford it buy both his books and increase their own knowledge and understanding of the processes at work in the soils around and under our built infrastructure, and how trees fit into that interaction. http://www.willowmead.co.uk/ __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup

22nd July 2007, 03:46 PM	#20
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	Be very interested to know how old the trees were, and how old the houses affected were...ie when where they built....what type of foundation slab was laid and over what sub-base. On truely reactive soils the only long term foundations I know of are slabs with reinforced stiffened beams across the span every 4/5m or waffle slabs with the floor slab placed on top...both are more expensive and take longer to prepare and lay than simple floating raft slabs. Consequently they don't get built very often. I have the distinct feeling that what was done even 10yrs ago will not last on top of reactive soils for another 10yrs...even if you could claim 50yrs life span for a concrete and block construction seems insignificant compared to the most moderate estimates of the life span of a healthy gum tree, something amiss there imo. Constructing a moisture barrier around the foundation whatever its quality would definately give greater protection than any post construction attempt to rectify subsidence...but again that would cost, and developers and builders are all for keeping the costs down for the potential home owner __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup

22nd July 2007, 04:43 PM	#21
Ekka Admin - Dip Arb & Hort & Seldom Wrong Join Date: Jan 2007 Location: Brisbane Posts: 9,772	AS 2870-1996 is the standard for foundations but anything built before hand ... bad luck! I suppose you rely on the builder doing the right thing. Appears from this document that 300mm dia piers at approx 2m intervals are sunk to a more solid sub-base. http://www.bsa.qld.gov.au/NR/rdonlyr...encePolicy.pdf Now, I've been driving past new sites where they like to retain the odd gum tree and build like 2m away from it, so I wonder if the builders are doing the right thing. You'd have to be there when they pour the slab to know what sort of additional protection you got coz of the tree. Maybe we can ask a builder/geo-engineer to comment here? Who do you know? __________________ TAS Training & Assessment Services\| Arb and Hort Training available here Free Online Tree Value Calculator by TreeWorld Free Online TPZ and SRZ AS4970-2009 Calculator by TreeWorld Free Online Tree Surface Area and Tree Volume Calculator by TreeWorld Free Tree and Green Industry Deep Link Directory ... Yes, I also SEO (Optimize) and build websites that fly high in Google Qualified Brisbane Tree Lopping \| Stump Grinding Brisbane Brisbane - Gold Coast Consulting Arborist, Tree and Arborist Reports \| Project Arborist

22nd July 2007, 04:49 PM	#22
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	I've got to visit quite a large profile development site tomorrow I'll talk to the site managers and see what info I can glean from them, meantime I'll email you a couple of pdf's too big to post so you can see just how much tech analysis is supposed to go on even before any soil is disturbed...as you say makes you wonder when we visit some of the development sites up and down the state just how much unsupported box ticking is going on. __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup

22nd July 2007, 05:42 PM	#23
Sean Freeman PDF King & Arborist Extrodinaire Join Date: Feb 2007 Location: Townsville Nth Queensland & Gold Coast Sth Queensland Posts: 2,155	Here's a pdf that gives us something of an insight into the problems and complexities that exist between geotechs, struct engineers, architects, and builders...oh yes and the home owner! Not solely pertaining to the issue at hand, trees but very informative non the less..the better we understand their world and their concerns the better we can help them to improve the management of trees in this messy web of interactions! Pitfalls_Risks.pdf __________________ Sean Trees are poems that earth writes upon the sky, We fell them down and turn them into paper, That we may record our emptiness. - Kahlil Gibran http://wanderingarborist.blogspot.com/ http://veterantreegroup.blogspot.com/ http://www.youtube.com/user/VeteranTreeGroup

23rd July 2007, 09:18 PM	#25
Ekka Admin - Dip Arb & Hort & Seldom Wrong Join Date: Jan 2007 Location: Brisbane Posts: 9,772	I also have information regarding appropriate root barrier. Partly in the document attached which I scanned from the report and converted to PDF pic files. It's 6.57mb in size, I cannot find the document on CSIRO's website. In addition (from the geotech report) states the trench should be 100mm wide and 2m deep, filled with concrete with a maximum aggregate size 10mm strength 15mPa, preferably at least 2m away from house foundation. As I thought earlier, a simple typical plastic root barrier sheet wouldn't suffice as it will bend if soil wants to move. So to construct barriers like this is expensive and means you'll have to get a trencher or backhoe in. In effect the barrier is some sort of subterranean retaining wall in addition to root stopper. Document also has a list of bad tree species. http://www.treeworld.info/manualuplo...oundations.pdf __________________ TAS Training & Assessment Services\| Arb and Hort Training available here Free Online Tree Value Calculator by TreeWorld Free Online TPZ and SRZ AS4970-2009 Calculator by TreeWorld Free Online Tree Surface Area and Tree Volume Calculator by TreeWorld Free Tree and Green Industry Deep Link Directory ... Yes, I also SEO (Optimize) and build websites that fly high in Google Qualified Brisbane Tree Lopping \| Stump Grinding Brisbane Brisbane - Gold Coast Consulting Arborist, Tree and Arborist Reports \| Project Arborist

24th July 2007, 05:09 AM	#26
Oldtimer Semi-mature vigorous tree Join Date: Jan 2007 Location: Austin TX Posts: 105	There is a whole industry in the US dedicated to the "leveling " of house foundations. Some of the houses were built on very plastic clay soils with high shrink and swell capacity due to seasonal variation in the amount of moisture on the soil. So foundation cracks or the walls cracks on the house are common. My house is in a subdivision with caves all over, there are many houses that show the signs. Also, There is one that has a tree actually touching the foundation of the garage and there is no obvious indication of damage. ( the tree is Soooo close to the house that they actually cut a small portion ( about 2 ft by long by 1 ft wide) of the roof overhang to allow the tree to pass thru it. ( I will take a photo later for you to see it). Those cracks on the photo that Ekka posted are nothing compared to some of the nasty ones we regularly see around here. They have a pier system that they pressure inject below the foundations to repair some of the damage but most of the soils around here are marginal for the type of construction used by local builders. Good topic!

9th September 2007, 10:10 PM	#27
Roller Semi-mature vigorous tree Join Date: Feb 2007 Location: Suffolk UK Posts: 156	Re: Soil subsidence and trees building+clay soil+tree+fell.....!! __________________ www.arboraeration.co.uk Tree healthcare specialists covering the UK

9th September 2007, 10:26 PM	#28
Ekka Admin - Dip Arb & Hort & Seldom Wrong Join Date: Jan 2007 Location: Brisbane Posts: 9,772	Re: Soil subsidence and trees Roller This is big business in UK, I see many consultants offering services for trees in proximity to houses, subsidence etc. Some offer to gather evidence to remove liability for tree owners whilst others the opposite. If you have any reference material it would be great. __________________ TAS Training & Assessment Services\| Arb and Hort Training available here Free Online Tree Value Calculator by TreeWorld Free Online TPZ and SRZ AS4970-2009 Calculator by TreeWorld Free Online Tree Surface Area and Tree Volume Calculator by TreeWorld Free Tree and Green Industry Deep Link Directory ... Yes, I also SEO (Optimize) and build websites that fly high in Google Qualified Brisbane Tree Lopping \| Stump Grinding Brisbane Brisbane - Gold Coast Consulting Arborist, Tree and Arborist Reports \| Project Arborist

10th September 2007, 12:28 AM	#29
Roller Semi-mature vigorous tree Join Date: Feb 2007 Location: Suffolk UK Posts: 156	Re: Soil subsidence and trees UK Law Case Summary Delaware Mansions Ltd and another v. Westminster City Council. Court of Appeal, July 1999. Beldam, Thorpe and Pill LJJ. This case involved damage to a property by tree roots. In 1989 structural engineers reported that damage had occurred to some blocks of flats and that a Plane tree, which was owned by Westminster City Council, was responsible for the damage. The engineers recommended underpinning of the flats or removal of the tree. The council refused to remove the tree. The flats were sold in June 1990 to the second appellant company for one pound. The first appellant company was formed, and owned, by the tenants to provide maintenance and service to the flats. These companies were seeking damages from Westminster City Council for the cost of the remedial works carried out to repair the foundations of the flats, and which cost some ?570,735 pounds. However, their claim was dismissed on the grounds that they could not claim for the damages because the damage had occurred before they had become the new owners of the flats. The plaintiffs appealed and won. During his judgement, Pill LJ said "Thus, where there is a continuing nuisance, the owner is entitled to a declaration, to abate the nuisance, to damages for physical injury and to an injunction". And, "If the council had agreed to remove the tree when asked, the damages would have been very small. In the circumstances, which are probably unusual, the fact that the nuisance existed before the second appellant became the owner is irrelevant". __________________ www.arboraeration.co.uk Tree healthcare specialists covering the UK

10th September 2007, 07:37 AM	#30
Ekka Admin - Dip Arb & Hort & Seldom Wrong Join Date: Jan 2007 Location: Brisbane Posts: 9,772	Re: Soil subsidence and trees And hence it should be. Frankly, if something in your property does damage to mine, then you pay. Fair and simple. You want a tree, then ensure it does not trespass either above or below the ground. Installation of an adequate root barrier would also have prevented the problem. If the tree owner thinks it unreasonable to fork out say $10,000 for an engineered suitable concrete permanent root barrier then how could they consider it fair and reasonable for the victim to fork out much more than that? Thanks Roller __________________ TAS Training & Assessment Services\| Arb and Hort Training available here Free Online Tree Value Calculator by TreeWorld Free Online TPZ and SRZ AS4970-2009 Calculator by TreeWorld Free Online Tree Surface Area and Tree Volume Calculator by TreeWorld Free Tree and Green Industry Deep Link Directory ... Yes, I also SEO (Optimize) and build websites that fly high in Google Qualified Brisbane Tree Lopping \| Stump Grinding Brisbane Brisbane - Gold Coast Consulting Arborist, Tree and Arborist Reports \| Project Arborist

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