The buildup of woody vegetation due to clearing legislation is impacting stream flows, biodiversity and fire risk, Councillor Gary Verri says, and Tenterfield Shire Council is backing his push to lobby state and federal politicians for a comprehensive investigation into its unsustainability.
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Notice of Cr Verri's motion at February's council meeting drew three speakers on the issue, two in support and one against.
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Mingoola farmer Bob South has long been of the opinion that allowing the buildup of vegetation along waterways has diminished the volume of available water. On behalf of the Mole & Sovereign Water Users Association he sought council's support for a separate request for funding for a research program on the Mole River (which will be tabled at a later meeting), but said farmers often get lost in the system.
"Everyone has an opinion on the value of trees along waterways," he told the meeting.
"If the information (in Cr Verri's report) is relatable to Australia, probably the biggest risk to Tenterfield's water supply is an increase in riparian and other vegetation in the catchment." (The riparian area is the interface between land and a river or stream.)
Mr South is also proponent of independent research on the issue, saying there are large gaps in the information at hand. He said there's been a lot of emotional and political opinions put forward, now it's time for factual opinions.
He said he's not suggesting tree removal, just some research into the facts.
Moving from stream flow reduction to fueling fires, Geoff Robinson (who came from a stint in hospital after fighting bushfires brought on an asthmatic condition) recalled wildfires going through his Boonoo Boonoo property in 1983 and 1994, and again in 2002 when only the house was saved.
He said he finally finished 18 kilometres of replacement fencing six months ago, only to lose it all again in the lastest inferno.
"My 80-year-old wife was up on the roof with the hose while I put out spot fires," he said.
"We can't do it again."
He feels the biodiversity that the legislation is aiming to protect is suffering under the regime, citing the incidence on his property of black glossy cockatoos as an example. There were always five breeding pairs, but after the 2002 fire only one pair remained.
They fed on the casuarina which has been incinerated, so he fears they're lost now as well.
He noted concerns about the demise in koala populations due to urbanisation, but said they should be protected where they do live.
"If people are concerned about the koala population, they should be worried about bushfires."
In his report to council, Cr Verri said that up until around 1990 stock routes and other Crown land was burnt regularly -- in some cases annually -- and most landowners also burnt on a regular basis.
Quoting historian Geoffrey Blainey, he said that 50 years was sufficient for the landscape of south-eastern Australia to change character when European farming suppressed aboriginal fires, and the rampant ringbarking of trees at the turn of the 20th century was an effort to re-establish the land's original carrying capacity.
"Australian Ornithological Union records, going back to the 1800's, show that the marked decline in granivorous (grass-seed eating) bird assemblages in Queensland's desert uplands preceded any land clearing activity," his report said.
"Meanwhile it is well known that increasing tree cover severely depresses understory grass production, especially on dry, infertile sites. In other words: more trees, less grass, fewer granivorous birds."
Cr Verri said this decline in bird numbers has increased dramatically in the past three or four decades, as thickening woody vegetation crowded out grass.
He said tree cover in a catchment area reduces flows into farm and civic dams, citing a US example where landholders in Texas are actually being paid to clear trees in order to enhance the San Antonio water supply.
He fears a rising probability of what he calls 'holocaust' fires in the absence of an active controlled burning program. He said the recent fires around Boonoo Boonoo highlighted the importance of regular burning.
"A large area that was burnt last year suffered none of the devastation that the rest of the area suffered. The grass is still green, there was no crown fire.
If the stock route was burnt on a regular basis as it used to be, this fire would have been contained west of the Mt Lindesay Road.
- Cr Gary Verri
"In fact if the stock route was burnt on a regular basis as it used to be, this fire would have been contained west of the Mt Lindesay Road."
He said extremely hot, intense fires like we have just witnessed destroy much of the fauna and flora.
"Experience shows it takes three or four decades for the epiphytes to recover, and leaves the land open to erosion when it rains."
Councillors resolved to write to state and federal representatives requesting a comprehensive investigation into the unsustainability of excess woody vegetation, and its effect on stream flows, woodland species and fire.
Better land management instead of clearing and burning off will reduce fire threat, opponent says
Passionately opposed to the move is Lana Tyacke, who also addressed council during the public access session. She agreed that the globe will continue to dry without changes to current practices and also that, in early settlement, native animals and birds were abundant and the land was covered in well-spaced, tall canopy trees dotted through good pastoral land.
She said that tree loss has led to the decline in wildlife and has restricted animal movement, while cultivation has affected the soil's ability to function as nature intended. Soil compaction creates an environment for weedy species to grow, as evidenced by the proliferation of love grass.
With the soil's ability to absorb water it is now drained off the landscape to eventually end up in the sea. She blames this drainage for lowering the water table, eroding river banks, creating drought and increasing the fire hazard.
"We can hydrate the earth very simply and efficiently by implementing water harvesting systems to the landscape to slow, spread and sink water," Ms Tyacke said.
"We have a perfect window of opportunity right now to plan and implement water harvesting systems. Our creeks are dry.
"Let's prepare to rehydrate our region with the next flood event, for water security."
This is by way of installing leaky weirs, re-instigating meanders and creating chains of ponds. These are designed to back up silt and slow the water flow and raise water height, allowing large rain events to reach the flood plains.
Swales on contours will also slow, spread and sink water, as does a Yeomans plough used to crack the hardpan without disturbing the soil. Green waste can be turned into compost tea to support the establishment of missing soil micro-organisms, generating productivity gains for farmers.
She said moist soil means more evaporation leading to higher air humidity creating clouds to release soft rain to the soil to complete the cycle.
Furthermore trees in riparian zones, rather than sucking up water instead make rain through transpiration. Firefighting could be aided by installing 'domed' fire trail access roads on a contour with swales below, to again capture and sink water.
Ms Tyacke also suggests bringing back the shepherd profession, as moving herds of goats are a valuable addition to fire hazard reduction. Dense mobs of livestock that are kept moving are also a tool. Mushroom spawn inoculation can be used to decompose excessive litter.
She said deliberate burning off, however, releases carbon to the atmosphere and destroys the organic matter which acts as a sponge to buffer the dry times.