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Feasting Lorikeets
1. The Newcastle community have taken the axing of the Laman Street Figs to the Land & Environment Court today. In their favour is the Arborist’s Report prepared by Mark Hartley. Mr Hartley assessed the trees as not dangerous & had serious concerns with several mistakes in previous Reports supplied by Newcastle Council. I hope the community win. You can read about the decision & the Independent Arborist Report here – http://savingourtrees.wordpress.com/2010/09/01/independent-arborist-report-for-newcastles-laman-street-figs/
2. In a great move to support Wolli Creek being established as a national park, Canterbury Council have agreed to transfer part of the Wolli Creek bushland at Earlwood to the National Parks & Wildlife Service. The land is between Bexley Rd & Waterworth Park. http://express.whereilive.com.au/news/story/vote-brings-planned-park-a-step-closer/
3. Large amounts of Eucalypts are dying across Australia & it is thought to be caused by Bell Miner Associated Dieback. One little bird guarding the psyllid, a sap-sucking native insect that provides food for the Bell Miner is thought to be responsible in some areas. In New South Wales alone, up to 2.5 million hectares of forest are wasting away. Another theory published in 1968 by ecologist William Jackson of the University of Tasmania & regaining favour is that the Australian bush needs regular bushfires to survive. Interesting reading. http://www.newscientist.com/article/mg20727772.200-receding-gums-what-ails-australias-iconic-trees.html?full=true
4. Frightening results in a recent survey about climate change of local, state & federal Australian politicians conducted by the University of Queensland. Of the 300 politicians surveyed, nearly 70% believed anthropogenic climate change was real, but “more than 40% thought a temperature rise of 4 degrees would be safe.” Scary stuff as these people are making decisions for all of us. http://www.abc.net.au/news/stories/2010/08/12/2980671.htm
5. 2 Fig trees were to be removed in Kensington by the City of Perth Council without community consultation. The Council said the trees were damaging the footpath & could affect fibre-optic cables. Well roads can be fixed, so can footpaths & fear that a tree may damage underground cables is a pretty poor excuse to remove the Fig trees. I wish Councils would use floating or permeable footpaths to allow them to keep trees. These trees would far outweigh any concrete or bitumen in value & benefits to the community. It’s that old way of thinking again, rip out a tree-it’s the easiest route. The City of Perth Council will now do community consultation about these trees. http://www.inmycommunity.com.au/news-and-views/local-news/Threat-to-trees-angers-residents/7568257/
6. By contrast, Brisbane City Council ordered a redesign of the $10.2 million Perry Park upgrade to save a row of Fig trees. A spokesman said council policy was to retain “mature, healthy trees” where possible. In QLD, trees & street landscaping is everywhere & is wonderful. It really looks like a different country. Loud applause from me. http://city-news.whereilive.com.au/news/story/fig-trees-slow-upgrade-start/
7. A row of 14 old, ‘ulgy’ & ‘past their use by date’ Nicolai gum trees along Chiefly Road Lithgow will likely have been chopped down by now. Lithgow Council said “the trees had been inappropriately pruned in past years by electricity authorities.” I’ve no doubt that this approach to Lithgow looked old & ulgly. Shame it happened in the first place. I wonder when this cycle of tree management will end. http://www.lithgowmercury.com.au/news/local/news/general/tree-removal-an-environmental-necessity/1936892.aspx
8. A report done by the WA Environment Protection Authority said “declining rainfall & rising temperatures were taking a heavy toll on parts of the 1.2 million hectare state forest area south of Perth.” Paul Vogel, the head of the Environment Protection Authority said there was “more biodiversity per square metre in some of these forests than there is in the Amazon.” The Conservation Council, WA Forest Alliance & Wilderness Society want clearing & logging stopped immediately in affected areas. 850,000 hectares of WA state forest is available for logging, however, the current management plan is deemed severely lacking. http://www.perthnow.com.au/news/western-australia/environment-watchdog-warns-against-logging-in-west-australian-forest/story-e6frg13u-1225921967989
Grevillea flowers
Sometimes I get annoyed with Marrickvile Council & sometimes I think they do such fantastic things for our environment that I want to become their publicity officer. Today was the latter. It is National Tree Day.
Council arranged a National Tree Day working bee for members of the community to volunteer by planting the new area currently being renovated at Steele Park, Illawarra Road Marrickville South alongside the Cooks River.
My initial impression when I arrived was one of astonishment. I had been expecting to see a small area that was to be a salt-water wetland. Instead before me were large decorative swales, at least 2 of them, with a couple more being built. One looks like a heart before it takes a winding route under a new pedestrian/bike path/bridge before reaching the Cooks River. The car park has been removed, the soil has been landscaped to facilitate the swales & new trees have been planted.
Council supplied gloves & spades & put on a barbeque. We were given on-the-spot OH&S training before we joined around 60-100 other people to plant native grasses, ferns, shrubs & seedling trees. The work was easy because the soil was wet after the recent rain. It looked like 4/5ths of the plants were in the ground by the time we left.
If you haven’t done this before, I’d recommend it as a nice way to spend a couple of hours. People were friendly, the work was not back-breaking & the food was probably good, though we didn’t stay for that part. It was good to take part in beautifying this part of Marrickville.
There are a number of environmental programs in Marrickville LGA that rely on volunteers. For information contact Marrickville Council’s Biodiversity Coordinator 9335-2222.
I predict Marrickville Council will win awards for the landscaping & environmental work at Steele Park. When they do, I’ll post a reminder to say I said it first. If this is any indication of what the waterplay section is going to be like, Steele Park is going to be beautiful. As I write this it is raining – excellent for today’s new plants.
Showing a few shots of the swales. Second photo down on the right shows the salt-water wetland & the photo bottom left shows permeable footpaths.
The Hornsby Advocate wrote last week about a brilliant new stormwater management plan by Hornsby Council to filter stormwater & water street trees at the same time. Hornsby Council will install 3 tree-pits. These tree-pits capture stormwater from specially installed gutters. The stormwater is then filtered through soil, sand & gravel.
It’s such a simple idea, one wonders why this technique hasn’t been used before & why it isn’t put in place with all new street tree plantings. It would certainly go a long way to preventing tree deaths due to lack of water.
The paper published a diagram of the tree pits. Unfortunately I can’t post the picture here due to copyright, but it is well worth a look.
New footpath in Canterbury LGA & not one street tree planned. A cement desert.
Community tree preservation groups Save Our Figs Wauchope & Save Our Figs Group have a big fight on their hands with Port Macquarie-Hastings Council who intend to remove 13 Fig trees in the town centre “to prevent future damage to private property & public infrastructure.” The roots of the Fig trees are presenting a trip hazard & 3 residents have complained of damage to their property they say was caused by the trees.
These 2 massive Figs next to Marrickville Youth Resources Centre enhance the building & the area.
Thing is, the Council have just completed major works on the streets with the trees described as the centerpiece. Importantly, 3 years ago the community fought to retain these trees & won.
Now the threat of litigation has reared its head & if history is anything to go by, a very small number of people are going to get their way & have the trees removed. Council can’t take the risk that people will start litigation in the future.
A couple of days ago I posted that Goondiwindi Regional Council chopped down healthy Fig trees despite community opposition. It’s the same story. Now that the trees are gone, the Council has made the decision to spend $96,000 on floating footpaths. They are doing this now because they, “understand how important these trees are to residents.”
Using floating footpaths means the trees can grow normally. There is no need to cut off or shave down roots, nor cover them in bitumen. Nor will they need to chop the trees down because of a trip hazard or damage to footpaths. Seems like sensible spending to me. Given that any large healthy tree can be worth around $100,000, spending money to keep them is a good economic decision.
This Fig is literally holding the building up. There is no visible damage to the exterior of the building
The large street trees in the centre of both these towns are what bring beauty & a sense of place. The towns use their street trees as a tourist draw card. The Fig trees also provide a tangible history & are held dear by most of the community.
Take the trees away & you have substantially changed a place. Not only have you removed things that are worth a great deal of money & with 13 Figs we are talking in excess of a million dollars, but their loss will have an impact on spending in the shops. Researchers have concluded 11% more money is spent in shopping areas where there are big healthy shady trees. To their credit Port Macquarie-Hastings Council plans to replace the Figs with 11 advanced Brush Box trees.
My question is why don’t Councils or organizations take pre-emptive action on their big trees when the trees are in areas that could damage property or cause trip hazards? Ultimately it is worth the financial outlay when one considers how much these trees are worth in a monetary sense. Then there are all the other factors to take into consideration, history, place, future, community cohesion (fights like these in small towns could escalate into severe divisions), trust in the Council/organisation & stating the obvious, climate change.
These roots have infiltrated a parking area. I found it interesting is to see that the roots didn't travel far from the tree despite its size. It has been like this for years & the tree is still healthy even though cars park on the roots, proving it is unnecessary to remove a tree when this happens. It might look unsightly, but the tree itself is gorgeous.
Root barriers can be put in place. Sewerage & water pipes can be replaced with pipes that can’t be invaded by tree roots or re-routed & be done with the problem forever. In Canada, they use a system that allows pipes to be replaced without digging, disturbing or damaging tree roots. They use a water flushing vacuum system to remove the soil from around the roots, pipes or wires, then install the new pipes & put the soil back in.
You don’t even need to put in concrete foundations near a tree when you are building anymore. Again in Canada, they insert giant steel screw piles into the ground that are just as stable as concrete foundations & require no digging.
There is also a high-density plastic grid system that I have seen used in Sydney. Once laid over the ground the grid disperses the weight of vehicles over a larger area. The grid also prevents soil compaction, which can damage roots. Best of all, the grid allows rainwater to permeate the soil, reducing the need for irrigation & improves storm-water management. Ground cover or other plants can be grown in the spaces within the grid.
The grid also prevents soil erosion. I can see these grids used to support riverbanks & to create cement-free car parks. They could also be used to channel water into the ground near a street tree rather than be wasted by pouring down drains. There is no reason why a section of the gutter cannot be a grid.
There is also porous concrete used across City of Sydney & North Sydney Councils. Porous concrete provides a seamless surface allowing people to walk across it, but still captures any rainwater that falls on it, watering the tree.
There are quite a number of beautiful Figs in Marrickville LGA & many of them are planted near buildings. Unfortunately many of these trees live in less than perfect conditions with cement & bitumen almost to the base of their trunk. Many have cars & trucks parked right next to them. As we have seen, it is only a matter of time before branches get gouged or broken off by trucks.
Canary Island Palms line Graham Avenue Marrickville. I hope these trees are heritage protected.
The only reason why money isn’t spent on protecting trees before problems start is that trees are not held in high importance or the Council is so strapped for money that understandably, urban forest issues get moved down the list of priorities.
Many Councils do hold their trees in high esteem & look after them. They use floating footpaths & permeable rubber surfaces or permeable ‘solid’ surfaces. They put garden beds around trees to prevent or limit the amount of vehicles that can park under them. They put ‘no parking’ signs for vehicles over a certain size & weight & they do other things like prune dead branches & normal die back. They probably feed them occasionally as well.
I would do all of the above & if property damage occurred with people saying get rid of the tree/s, I would think it is the community’s & Council’s best interest to fix the damage (within reason, once proof & access has been given to Council) & put things in place to ensure the problem won’t repeat itself. Too many people & future generations miss out for cracks to walls & pipes, both which are easily fixed without costing as high as the value of losing a tree.
Trees are the only things Councils own that increase in value each year.
I have written about clay soils & how they affect buildings at – http://savingourtrees.wordpress.com/clay-soil/
You can read both stories at the following links -http://www.portnews.com.au/news/local/news/general/lastditch-figs-effort/1874281.aspx
A selection of new garden beds in Robert Street Marrickville
We came across new footpath work in Robert Street Marrickville yesterday. Marrickville Council has replaced the footpaths & created large garden beds around street trees planted on verges. It’s happening in other streets so it appears to be a new trend. I sincerely hope so.
The first time I saw this done was earlier this year in Ivanhoe Street Marrickville South & I was impressed. The garden beds are twice as large in Robert Street because the footpaths are wider.
As well as the street trees on the verge, Robert Street has beautiful old Brush Box trees that were planted on the sides of the road around 80 years ago. Council has created garden beds on the verge next to many of these trees, which will allow these trees to be able to get a good drink when it rains. These trees have suffered decades of bitumen almost to their trunks so they should respond well & live longer now they have better access to water. Council have planted native grasses & Pig Face (I think) & in a year or so, they should look very pretty.
Unfortunately, works like these can cost many thousands of dollars (a tiled footpath outside a small group of shops can cost $60,000) so I would imagine that it would be a slow process creating these types of footpaths as the norm throughout the LGA. However, it’s worth waiting for.
It is good that by creating these garden beds, the amount of cement coverage has lessened. Not only will the trees get more water & the streets look greener, but the street should be cooler during summer as well.
Is less cement an issue? I think it is & so do many experts. Urban areas are much hotter than non-urban areas because cement & building surfaces can trap heat from the sun. This is called the ‘heat island effect.’
The flying foxes that left Queensland to come & live in Sydney’s Royal Botanic Gardens for the past 20 years or so have made their home there because the air temperature is to their liking. The walls of the tall city buildings, roads, cement surfaces & roofs of the CBD have raised the air temperature & created a climate suitable for the bats. In the city it is called the urban canyon effect because the walls of tall buildings form canyons that capture & hold heat.
Air temperatures can be up to 12 degrees hotter in cemented areas during summer. I have read up to 50 degrees hotter, but this is probably in desert areas. Much like a car parked in the sun with the windows closed, environments can become heat boxes keeping night temperatures warmer. A 2005 study showed urban air temperatures being up to 12 degrees warmer at night during summer than in rural areas.
Apart from the obvious increase use of power needed to cool houses & the associated costs, the heat island effect also impacts on air quality & health as it causes smog & ground level ozone. Ground level ozone causes respiratory problems like asthma, coughing & lung damage. It can also cause chest pain & heart problems. This is why research shows that living within 500 metres of a main road can cause significant health problems. See – http://savingourtrees.wordpress.com/2010/06/29/living-close-to-a-main-road-is-bad-for-your-health/
Ground level ozone is also a factor in global warming. The heat island effect can raise the temperature so much that it causes heat events where heat waves are exacerbated. These events can cause death, particularly in children, the ill & the elderly.
There is also another issue with the heat island effect & that is storm water runoff. If the runoff is heated by pavements, gutters & roofs, it may be very warm by the time it reaches rivers, ponds & lakes & we have a few in Marrickville LGA. This hot water can cause death to fish & other water life as well as increase the growth of blue-green algae that sucks all oxygen out of the water causing more fish death.
This is a very basic outline of the heat island effect & I will be writing about it in more depth in a later post. However, I hope what is written so far is enough to understand why our society’s love for cement is a problem. Cement is easier, but it comes with it’s own problems & these problems follow us into our homes.
A couple of examples in Robert Street Marrickvillewhere residents created gardens to protect street trees. To me, they look great & are far better than bitumen up to the trunk.
It is my belief that we need to plant many more trees across Marrickville LGA. We need larger trees that create shade, both on private property & as street trees. Street trees that grow straight upwards & have a canopy of no more than 2-3 metres are not a ‘shade tree.’ We also need less cement & bitumen, more gardens & pockets of green space outside of formal parks to keep the heat down, for our mental & physical health & for the health of the planet.
Sydney is getting bigger & bigger & with this urban sprawl comes more cement, more hard surfaces & fewer trees. My fear is that, if climate change does happen in the way the scientific experts predict (& being a prediction, it has a 50% chance of being worse than what they think will occur), that we & our governing authorities will realise just how important trees & green spaces are, but the weather will be too hot & water in short supply that whatever is planted will have trouble surviving. Bleak I know, but I have read a lot on this subject & none of it is heartening.
So getting back on subject, what Marrickville Council is doing when they are replacing footpaths is terrific & sensible action for the future. It will allow people to get used to less cement & hopefully encourage them to be actively involved in the garden beds outside their property.
Tuesday’s Council meeting was perhaps one of the most important meetings of the year as the Asset Management Strategy Policy was on the agenda. This report was recommending to increase rates, always a hot issue when it hits the public purse.
Money was central to most of the issues on the agenda from a donation to Haiti, whether to spend money on Addison Road or on Marrickville Railway Station, to giving the Greek Orthodox Church in Marrickville financial assistance of $5,000 to quieten down their new digital bells & to the Asset Management Strategy Policy prepared by Council staff. There may have been more, but we did not stay until the end.
Many residents are aware that Marrickville Council doesn’t have the money to fix things as most requests from the community take a long while before they reach the top of the list of the actions council is taking. Staff & councillors have openly said to me on a number of occasions that Council just doesn’t have the money to do certain projects. For me, it was obvious when reading through last week’s Tree Management Issues Paper that Parks & Gardens have been functioning under-resourced & under-financed for many years. After what I heard discussed last night, I would not be surprised if many departments in Council are experiencing the same restrictions. Put simply, Marrickville Council finances are in trouble.
In brief, the Asset Management Strategy Policy prepared by Marrickville Council staff said:
- Marrickville Council cannot afford to look after its infrastructure & assets & was listed as an ‘unsustainable council’ in 2009
- Council’s financial unsustainability was not going to improve unless they improved their financial position significantly with one option being to increase rates.
A staff member said that the reason the report was before Council was because:
- the serious condition of our assets with significant issues facing Marrickville Council 2010-2011
- Size & scale of financial deficit is substantial. The draft budget first cut figure is $2 million deficit having carried through Phase 1 & 2 reductions to the budget
- There are a lot of unknowns if the issue is deferred for another year
Marrickville Council does not have enough money to repair its assets or maintain its infrastructure. A recent & public example is the old & beautiful Coptic Church in Sydenham Green, which featured in Council in 2009 & again last week.
It will be a significant loss to our history if we lose this building
A staff member of Council explained to me that a community organisation can apply to use the church, though they would need to sign a lease for a number of years & renovate the building themselves at an estimated cost of $2.3 million, as well as look after its upkeep for the duration of the lease before it comes back into Council’s hands again. The problem is that the community organisations or groups that council would see as suitable to use the church building are unlikely to be able to pay for the repair of this particular building which is deteriorating at a rapid rate. The Inner West Courier published an article about this church this week – page 9 -http://digitaledition-innercity.innerwestcourier.com.au/
The Asset Management Strategy Policy was recommending that the councillors decide whether or not to apply to the minister for a rates increase (special levy).
The debate between councillors covered the history of some projects & of previous applications for rates increases, how much public works actually cost (eg $350,000 for paving in Dulwich Hill shopping strip, $15,000 for a speed hump, $35,000 for a round-about) & about the financial burden of servicing 1 billion dollars worth of infrastructure before you even build anything new.
Despite the importance of the issue & the strong views held by councillors, the meeting was polite. There was negligible need for the chair to intervene.
The flow of the discussion allowed the councillors to ask many questions to the staff & I was impressed by the extensive & considered strategic advice they offered. They explained how these processes work, what is the financial situation of council, what could be done with any additional funds in the kitty & what might be done if council did not apply for the special levy.
Councillors expressed concern about the financial status of council. As expected, there was divergent opinion as to the best way to manage this situation. I am deliberately lumping comments & strategies together to keep this brief. Apologies for any mistakes.
The Greens expressed concern that Council was in dire financial straits & if left until next year, the situation would only worsen reminding that this issue has been deferred for many years. They believed if the community was asked whether they would pay about $1.60 per week per household or 96 cents per week for lower income households for better roads, better footpaths & better infrastructure, the majority of rate-payers would say yes. They were also worried about Council’s ability to pay staff & ability to maintain the substantial assets we have. They wanted the money raised to be used for priority infrastructure renewal works. They also reminded everyone that it has been 5 years since the last rate increase. They also argued that if left until next year, councillors will be afraid to pass a rate increase because of fearing community backlash with the upcoming election.
The remaining councillors wanted to defer the decision for another year saying that while they were concerned about Council’s financial situation, they wanted to know whether there were other cost saving measures & revenue accruing avenues that could be explored before going the route of raising rates. Some suggestions were closing some of the libraries, advertising on billboards facing the airport road at Tempe, life-cycle planning, community consultation with residents, continuing to educate council staff on safe work practices to reduce worker’s compensation payouts, looking at verge mowing & paid parking, increasing fees to use sports ovals & child-care facilities, getting rid of unnecessary programs & operations & selling off the Marrickville Hospital site (council has not made a decision about its future for some while).
The vote by Councillors Iskandar, O’Sullivan, Wright, Thanos, Hanna, Macri was to defer for 12 months.
We went to Berowra Waters today, which required driving up the Pacific Highway. The last time I did this I wrote about the street trees. This time I wanted to see specifically what the differences were between the Pacific Highway & the sections of Princes Highway & Parramatta Road in Marrickville LGA.
There were a number of noteworthy differences. The Pacific Highway has thousands of street trees along its length. A significant number of these trees are Eucalypts. They cascade over the highway, many having branches which cross over 3 lanes & sometimes as far as the opposite side of the highway.
Bottle Brushes are not the dominant street tree, with most trees being of a taller growing species. Many of the street trees are 1/3 higher than the power poles & thick trunks are quite common.
Far less than 50% of the trees have trunks that are as thin as an upper arm. Many street trees were planted around 3 metres apart, which helped create a decent canopy. Most of the trees have a natural shape & I did not see a single tree in a cage even within the shopping strips
The street trees planted in shopping strips spilled out from under the awnings & loomed over the highway. Naturally to achieve this they did not have straight trunks & they have not removed because of this.
Autumn colours
Much of the Pacific Highway has a grass verge with a narrow footpath. Only the shopping strips are paved or cemented. The grass verge serves to soften the environment, which is quite an achievement considering the Pacific Highway is one of the top 10 heavily trafficked roads in Australia. I watched the verge of the Highway for its length wondering how they were managing with far less cement. I noticed the footpaths were narrower than in the Inner West & many trees hung over the path requiring any pedestrians to either duck or weave their way around the tree. I actually saw this happen & it appeared to cause no difficulty for the pedestrian who was a woman over 50. So very different from here, where just last week a council worker took to our fence with a whipper-snipper to hack away 20 centimetres of errant camellia which protruded out from under the fence. Considering the footpath outside our fence is a wide one for the area, I thought this was overkill.
So do we sanitise & control nature more than they do on Sydney’s North Shore? I think we do.
In direct opposition is our section of the Princes Highway & Parramatta Road, both of which are an eye-sore in my opinion. The Princes Highway cannot possibly get uglier & being so close to the airport, it is one of the gateways to Sydney. The roads directly surrounding the airport were heavily planted with street trees, shrubs & flowers for the 2000 Olympics. In the main, they still look good & are maintained by Botany Council. I doubt once the visitor leaves these roads & comes to the Princes Highway that they will have a favourable impression of the area. The Princes Highway is in the main a worship of cement. Soot stained, dirty cement. One can count the street trees & they are a sad, straggly lot. There is a gross lack of green infrastructure. This changes when the Princes Highway comes under the jurisdiction of City of Sydney Council at one end & Rockdale Council at the other. For a green council, Marrickville seems to be ignoring this stretch of highway.
The same can be said for Parramatta Road, which is stark in its lack of green infrastructure, though it is slightly less ugly than the Princes Highway because of the type of grey infrastructure (some may debate this). Again, Leichhardt Council & City of Sydney Council have planted threes where Parramatta Road comes under their control, though City of Sydney Council has done far more work & planted many more street trees. If City of Sydney, Rockdale & Leichhardt Councils can plant street trees along these main roads, why can’t Marrickville Council?
Red-flowering Gum provides food for the birds & possums
Why do we need so much cement? Trees help the longevity of grey infrastructure like cement footpaths because their shade protects from the harsh sun. We also know that roofs, roads & footpaths cause the heat island effect & trees lower this. Temperatures can be 9 degrees cooler in the shade of a tree.
The North Shore is deemed classier. I think this is not because of the housing stock, but because of the plentiful tall trees & the significant green canopy. Friends have told me they moved to the North Shore because of the trees. Balmain & Paddington were built as working class suburbs as were those in Marrickville LGA, yet both these suburbs are regarded as better suburbs & their properties are generally worth more. Why? Is it the presence of water? Being close to the city? Perhaps, but Marrickville LGA is also close to the city & has its own beautiful Cooks River.
I think it is because of the trees. On the drive back from Hornsby, the closer you get to Marrickville the more you notice the trees thin out, get shorter, look less healthy & street tree after street tree have been severely hacked. The trees on the North Shore aren’t hacked in this way.
What concerns me about the removal of street trees when they have been accused of causing damage to property is the following:
- We have just experienced a long & protracted drought & more than 3/4s of NSW is still regarded as drought-affected. The long-range weather forecasters say we have entered into another phase of drought. The Inner West has been affected, as has the whole of the Sydney metropolitan region. This drought has resulted in severe water restrictions & this has affected our soils to a great degree. Trees are stressed & quite a few have died within our local LGA. Many of the saplings Council plants do not survive the summer because they are not watered. This must result in significant financial loss to Council.
- Even though we had quite a bit of rain over winter, we are still on water restrictions. The park trees were able to capture much of the water when it rained, but our street trees have only a slight chance at getting a proper drink. Most of the street trees in our LGA have been given very little ability to capture rain water or storm water run-off. Most have a small opening left open amidst the cement or
Newtown street tree
bitumen. I have only seen 4-5 street trees planted in cement where I feel they have been given adequate soil space around them to give them a fighting chance to capture rainwater. Two were in a back street of Newtown & I doubt Council did this, as the kerb had been removed. Both these trees had a lot of soil around their trunk. The other example is new plantings bordered by raised brickwork on Unwins Bridge Road Tempe. I think it would be wonderful if all our street trees that are in cemented areas could be planted in this way. I would also very much like to see Council give funding for the watering of young street trees as they do in other Councils.
- Much of the Inner West is built on clay soils. Clay soils are quite volatile as they shrink when they do not get sufficient water & expand when there is too much water. Both these extremes affect the foundations of buildings & footpaths. The term Seasonal Fluctuations describes the normal variations of the moisture content of clay soils through the seasons. When clay soil gets a lot of water it is called Field Capacity. When the soil is dry due to evaporation, heat & lack of rain during drought it is called Desiccated & suffering from Soil Moisture Deficit. If a drought is lengthy & the soil does not return to Field Capacity after some rain & then enters into another dry period, it is called Persistent or Permanent Moisture Deficit. This is likely to have already occurred in the Inner West or will do during the next period of drought in which we are now entering.
- Soil movements cause what is termed Subsistence & Heave. With Subsistence, the soil moves downwards. With Heave, there is an upwards or lateral move of building foundations or footpaths. While the clay soils go through Seasonal Fluctuations foundations of buildings don’t move much, though that depends on how much clay soil is directly under the foundations. When the clay soil suffers from Persistent Moisture Deficit, foundations of buildings move & walls start to show cracks, paint peels & doors & windows are suddenly off balance. Just last week our front door over night became hard to open & stiff on its swing. It is recommended that you don’t fill in the cracks or shave wood off door or window surrounds when the ground is dry, but wait until the soils have returned to normal moisture content before doing repairs. Most times the doors & windows will realign & the cracks will come closer together though paint work will need repairing. If you do fill cracks while the soil is dry, the space will not be available for the building to move back into place & new cracks will appear, generally on the other side of the building.
- The experts suggest occasional watering of the exterior of the house as this will help keep the clay soil moist so that your foundations don’t move during a drought. In my case, I have been keeping the water up to the back garden, but to save water, I have left the front garden manage as best it can. Here is the reason why our front door has moved. Also, it is our hallway & the front room that are suffering the cracks & peeling paint.
- My research has shown that trees can increase the seasonal movements of clay soil, however, engineers also stress there are too many factors to consider before one blames the presence of a tree for causing the damage. One of the problems is, if a mature tree is removed, this has a major impact on clay soil moisture & the property can actually sustain more damage as the soil fills with water & starts a process of Heave. It is hard to stop Heave because there is no longer a tree to be taking up the excess water. Because it is so difficult to categorically say that tree roots cause damage even if the roots do go towards & under the house, many engineers recommend using water to restore the water levels to clay soils rather than removing the tree. I have read that a tree is not able to lift a house because of the weight of the house. A footpath is a different story.
Trees ... we need them
There are things we can do to minimize or prevent further cracking or movement of buildings which do not involve removing trees. According to eminent scientists, we have entered a dangerous period of existence with CO2 levels actually threatening life on this planet. All agree on the supreme value of trees.
Just today in Copenhagen, the Food & Agriculture Organisation of the United Nations & Brazil’s National Institute for Space Research signed an agreement to work together in the field of emissions measuring and reporting by monitoring forests & calculating CO2 sequestration. Essentially they are going to map & monitor the green canopy of forests of the world. This clearly demonstrates the value of trees in dealing with climate change. We should only be removing them after all options have been exhausted.
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