What’s special about this?

A strong group took on FOBIF’s walk to Middleton Creek yesterday, our first open  walk for many months. Middleton Creek is a marvellous waterway, characterised by interesting twists and turns and rocky cliffs. Unfortunately it’s currently overrun with gorse and other weeds, evidently spreading from nearby private land, which obscure the creek’s interesting features. Fortunately the surrounding bushland in the Park is pretty weed free, and features a variety of vegetation communities, including patches of park-like serenity, like the woodland pictured below. The dense green carpets of Matted Bush-pea are striking even now. In spring its flowers are a spectacular highlight of this end of the Park.

Amanda’s Track, Castlemaine Diggings National Heritage Park: a wooded parkland of Matted Bush-pea and tussock grass.

FOBIF’s walk took in the very southern fringe of the Diggings Park, before swinging over to the Goldfields Track through Brown’s Gully. It finished with a short traverse through the zone of DSE’s disastrous 2010 fuel ‘reduction’ burn, which managed to multiply the area’s fuel load dramatically.

Part of FOBIF walking group in Brown’s Gully. The Candlebark eucalypts are among the highlights of the Goldfields Track through this area.

Our thanks are due to walk leader Bernard Slattery for this excursion. Next month’s walk is in the Pilchers Bridge NCR: check the walks program for details.

Middleton Creek in a wet year (2010): note the gorse infestation to the left of the picture. The National Heritage Park is relatively weed free.

Photos below were taken by Liz Martin. Click to enlarge. 

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Full report on March geology excursion with Clive Willman

Our first fobif event for the year was a geology excursion led by Clive Willman on 21 March 2021. We wrote a summary of this on the website and now Cassia Read has written a comprehensive and extremely informative report.

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Clive Willman led members of FOBIF on a fascinating geological tour, exploring the dynamic history of volcanoes and rivers that shaped landscapes in the Mount Alexander region. Evidence of this history was visible in rock profiles and landform features at five different stops visited around Castlemaine and Guildford. The ancient story told by Clive at each of these stops is described below.

Figure 1 Clive Willman “waxing lyrical” about the mighty, ancient Forest Creek (Photo Bronwyn Silver)

Stop 1: Forest Creek Historic Gold Diggings Reserve

A short walk north of the Diggings Reserve carpark brought us to a 10m deep cutting, down through ancient alluvial sediments. The cutting was formed by miners digging and sluicing in their search for alluvial gold amongst gravels deposited by ancient rivers. This cutting reveals a profile through sedimentary layers that tell a story of high energy rivers that flowed across the Mount Alexander region around 60 million years ago (mya). At this time Gondwana was breaking up and Australia split from Antarctica to begin its slow migration north. These tectonic movement caused major deformation of Eastern Australia and the uplift of the eastern highlands. The elevated gradient of these uplifted mountains, combined with the cool, wet climate of the time, created high energy rivers that flowed north from the divide. Evidence of the energy in the ancestral Forest Creek can be observed in the poorly sorted boulders, cobbles and gravels that make up the lower layer of the profile. Much higher flow rates and water volumes than we see today were necessary to transport these large materials through the rivers course. Over time the energy in the rivers declined, perhaps as the climate dried or the slopes of mountains eroded to be less steep, until they transported and deposited only smaller cobbles and sand with pebbles and clay – now visible in the middle layer of the profile. Another episode of high energy flow followed which again bought courser material down the river to be deposited in the upper layer of the profile.

Figure 2 This profile at the Diggings Reserve indicates wide variation in the flow of Forest Creek over geologic timescales, with boulders and cobbles at the bottom and top of the profile deposited during periods of high flow rates and finer sediments in the middle of the profile deposited during periods of low energy flow (Photo Bronwyn Silver)

Layers of coarse material in the profile became very hard conglomerate rock. Cementation occurred as iron oxides leached out of water moving through the gravel layers and then strongly bound sediments together as the ground dried out. These almost impenetrable cemented layers greatly frustrated the miner’s efforts to reach gold in the lower layers of the profile.

Stop 2: Old Guildford Railway Station

The railway cutting near Guildford revealed three distinct rock types within a few hundred meters distance and provides a window into key events in the geological history of our region. At one end of the cutting, an ancient bedrock of deep marine sandstones and mudstones could be seen. These were formed when sediments were laid down under the sea around 468 mya. These sediments washed off a mountain range to the west and settled in an ocean basin in layers. A phase of mountain building in eastern Australia around 440 mya compressed these sedimentary layers so they folded, much like a cloth on a Laminex table that is compressed from two sides to create a series of sharp folds. Evidence of the forces operating on these sedimentary rocks is seen in the almost vertical angles of these sedimentary layers (strata) on the face of the railway cutting.

Figure 3 Sedimentary strata are oriented  at near vertical angles due to folding and uplift of South Eastern Australia around 440 mya (Photo Bronwyn Silver)

A short walk northwards along the railway line (away from Guildford) brought us to a dramatic change in rock type, with cemented conglomerate rock overlaying the sedimentary bedrock. The pebbles and cobbles that make up the conglomerate were laid down by the ancient Loddon River, during the same period as the conglomerate from the ancient Forest Creek. In this area the layers of pebbles and gravels are cross bedded, indicating sections of the ancient river that were at an angle to the riverbed, such as longitudinal bar deposits. The interface between these ancient gravels and the bedrock is where miners found gold as alluvial gold settled at the bottom of the ancient rivers.

Trekking back towards Guildford brought us to a mining tunnel, or adit, dug into the sedimentary rock, where miners cut under the conglomerate to extract the gold bearing gravels above.

Continue reading

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…And what could possibly be special about this?

Think of a small, degraded patch of bush, surrounded by industrial sites and roads, only 4 kilometres from the centre of a sizeable city. It’s a tiny remnant of the ravages of gold fever, ‘symbolic of the way nature is now attacked and besieged on all sides.’ At just over 4 hectares, it has 50 mine shafts!

Why should anyone take an interest in such a place? Wouldn’t it be better just to look away, at somewhere a bit more encouraging?

To find an answer to these questions, have a look at Island with corners: Crimson Chats on the White Hills 2019. It’s the ‘complex story behind the Chinese Diggings Historic Reserve and the way it is today’, and is a 68 page large format book written by Bendigo field naturalist John Lindner. The  appearance of unusual birds on the reserve provoked the author to a detailed examination of the history of this patch of land, and his careful documentation of this history is an enthralling and instructive read. As he says, ‘Every now and again, a mere mortal may be astonished by something wonderful, beautiful and unexpected in Nature.’ This book recounts such an experience. It’s an object lesson in paying attention to our local neighbourhood (the author lives one kilometre from the reserve). At a time when there’s a bit of angst around about limitations on travel, perhaps there’s a lesson here for all of us: the next Big Thing in travel might be a seemingly unimpressive patch of land around the corner.

So: if you’re getting a bit downcast by the way the world is going, you could do a lot worse than spend some time on this book. It’s $25 from the author at jwl.bendigo@gmail.com

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Track the threat

Deer were sighted last week in the Middleton Creek area of the Diggings park. This feral species has now been seen in numbers in almost every corner of our region. Every credible community group, including farmers, municipalities and enviro organisations, has urged serious control measures against the exploding population: but, as we’ve reported, the State Government’s response to the menace has varied from the feeble to the supine. Its main agenda, on the face of it, seems to be to please the hunting lobby: a peculiar obsession, given that this particular lobby is generally hostile to the Labor Party.

If you’re interested in doing your bit to track the reality of this particular environmental problem, have a look at Feralscan. It offers ‘Many resources … to help you identify, monitor, or plan control of deer populations in your local area. View fact sheets, instructional videos, guides and strategies on best practice deer management. Use these resources as part of your coordinated control with your neighbours, local working groups, and biosecurity organisations.’ And it enables you to register any sightings you may have in your neighbourhood. Check out our 2019 post here–or go direct to the site at https://www.feralscan.org.au/deerscan/default.aspx

And: if you have the courage, you might want to read ‘The attack of the alien invaders’, an estimate of what feral species are costing the world, in dollar terms. It’s in ‘The Conversation’, today. You can find it here.

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This month’s FOBIF bush walk

The next FOBIF bush walk ‘Waterway and gully: Middleton Creek’ will take place next Sunday, 18 April. We will meet at the Community House in Templeton Street at 9.30. There is no need to register for this walk. All welcome. Contact Bernard Slattery on 5470 5161 if you have any queries. 

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Fire 1: ‘This time, it will be different…?’

FOBIF has received an answer from DELWP fire management to our questions about proposed burns in the Diggings Park in the areas of Helge and Wewak tracks.

Readers will remember we asked what lessons the Department had learned from its past efforts in this area, and how the future exercises would be handled differently. Here’s the answer:

‘I am confident in saying that we have learnt a lot from continually reviewing our practices and reflecting on what went well and what didn’t. You have identified 2 burns where aspects of the delivery was not as desired. There are learnings from every burn that are considered and adopted accordingly.

Large Candlebark brought down by indiscriminate DELWP’ ecological burn’, Tarilta valley 2012. FOBIF is concerned that the proposed burns could bring a similar result.

 

‘Along with engagement, rehabilitation is now a significant consideration in the planning of the burn. The Murray Goldfields now requires the Planned Burn Operations Officer (the officer in charge on the fireground on the day) to complete for every burn a;

  • ‘Post Burn Rehabilitation Check list (evening of burn day or the next day). This information is used to develop works plans for crews to carry out the required rehabilitation addressing issues such as signage, track rehabilitation and catchment protection measures.
  • ‘Post Burn Severity and Coverage document, capturing the coverage of the fire within the unit and its intensity.

‘We seriously review and consider our ignition options and plans. This is very much influenced by the fuels, the desired outcome and our crew safety. Seasonality is also consideration. Conditions as they present at the moment, find gullies still green after summer rains and therefore presents as a good opportunity to treat a burn without impacting significantly on gully lines. We have also observed that lower intensity burns seem to not generate as much fuel and accumulate fuels slower than burns that are generally burnt hotter. In addition, lower intensity burns generally maintain the Overall Fuel Hazard (OFH) levels under triggers for more years than higher intensity burns.

‘Backing this up is that Bureau of Meteorology (BOM) forecasting has improved which allows us to identify burn windows including follow weather and rain events with more certainty. During burning periods, the state establishes ongoing liaison with the BOM for weather forecasting including daily weather teleconferences and one on one liaison with Meteorologist.

‘I would like to reiterate that our staff both within the office and in the field are encouraged to reflect on their practice and provide feedback. This then informs our thinking and in some cases requires adjustments to our methodology. We pride ourselves in being dynamic and adaptive. I think you would agree that our approach to burning now is considerably different to how it was in the past.’

This letter is too vague to satisfy provide a convincing answer to our questions. In particular we don’t get an answer to this question:

‘What were the conclusions of post fire monitoring after the above two exercises [both as to ecological effects and fuel reduction]?’

Nevertheless, FOBIF is partly reassured by the implied admission here that hot burns actually generate fuel, rather than reducing it. We hope that this means a commitment to more care in the management of these fires.

It is true that managers are more aware of the complexity of their task than they used to be: but are the barbaric days of the past over, when burn methods seemed to be ‘throw in a match and watch it go’? We’re not so sure. For one thing, it never seems to be possible to see the documents referred to above: especially, we’d be interested in seeing the ‘post burn rehabilitation check lists’.

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Fire 2: Let’s see what is at stake

The two zones proposed for burning are between the Italian Hill track and the Wewak track, south of Vaughan Springs (see the map in our post). The northern section of this area was burned by the Department in the early 2000s. The burn was hot in patches: not only did it bring down a lot of trees, but it provoked substantial dense regeneration of eucalypts, rather counteracting the fuel reduction effect. The fallen trees did, however, block some wildcat trailbike tracks, thus reducing one scourge for a few years.

In Stone’s Gully, part of the proposed burn zones.

The two zones are strongly marked by past mining activity, and are crossed by the Goldfields Track. In spite of this, for many years they have been among the least disturbed parts of the Diggings Park. Fungi, lichens and moss beds are abundant. The gullies and creeks feature impressive Candlebarks. As FOBIF walkers found a couple of years ago, the ridges also feature unusually large trees. One of FOBIF’s concerns relates to this: that Department burns very often (unintentionally) bring down such trees.

Rock wall, Stone’s Gully. The area is abundant in moss, lichens and fungi.

One very major concern, however is this: the two zones seem to be too large to allow for any detailed management attention to be paid to ecological concerns.

FOBIF will continue to pursue this theme with fire officers.

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New twist for this year’s Camp Out on the Mount

Since 2013, Connecting Country, local Landcare, and other community groups have organised a free ‘Camp Out on the Mount’ event on Leanganook/Mount Alexander. This year, to reduce the risk of having to cancel or reschedule, they have decided to jump the gun, get creative and plan for a virtual ‘Camp Out on the Mount’.

When: 3 – 18 April 2021
Where: 
Online at www.connectingcountry.org.au/landcare/camp-out-on-the-mount-2021/

Asha Bannon, Mount Alexander Region Landcare Facilitator, says, “We hope to capture the ‘Camp Out on the Mount’ spirit by encouraging everyone to engage with our special ‘Camp Out 2021’ web pages, and inviting you to contribute to our ‘Camp Out Collage’.”

Each web page focuses on one of the elements that make the Camp Out special: ‘Camping out’ (of course!), ‘Caring for the land’, ‘Loving Leanganook’, and ‘Connecting with Indigenous culture’.

For each contribution you make to the ‘Camp Out Collage’ you will be entered into the draw to win one of several special prizes (maximum four entries per person), including a nest box, tubestock plants, and a native plants book bundle. Please note that you are only eligible to win the prizes if you live in Australia, and some of the prizes (such as the nest box and plants) will only be available for properties in the Mount Alexander region (central Victoria).

Anyone and everyone is welcome to participate, so hop online and join the fun! If you have any questions, please contact asha@connectingcountry.org.au

This event was made possible by the Victorian Landcare Facilitator Program, funded by the Victorian Department of Environment, Land, Water, and Planning.

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Making the stones talk

FOBIF’s March ‘walk’ yesterday was a geology tour of the district led by Clive Willman. Good numbers turned up despite the rain, which turned out to be reasonably friendly, though umbrellas did come out at one of the stops.

Clive William addressing the tour group at the first stop.

Volcanoes, raging rivers, and wet beech forests were all part of the picture Clive drew out of the stones to portray a set of pictures of this region over millions of years. We hope readers will understand that the plot is a bit hard to summarise in a few words: a fuller account will appear on this site in a few weeks.

Much thanks to Clive for his detailed preparation and compelling presentation: for the participants, those stones will never look the same again.

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The questions are…

As a follow up to Rob Simons’ recent correspondence with Forest Fire Management about two proposed burns in the Diggings Park (see the comment at the end of our last week’s post), FOBIF has written to DELWP’s Acting Regional Fire Manager, asking for a few details about the burns, which are slated for 2022 and 2023.

The two proposed burns are east of the Porcupine Ridge road, in the south end of the Diggings Park.. FOBIF is critical of two previous burns in this area, and is hopeful the Department can improve its performance this time around.

The letter reads:

A few questions arising from your recent exchange with Rob Simons about the two planned burns CAS 0244   and CAS 0245.

These two blocks are of course close to or contiguous with two previous Department burns, Tarilta valley and Loop Track, burned eight and ten years ago. You may remember we had an exchange of letters on the matter at the time.

On these burns there are in our opinion two undeniable facts:

  1. The Tarilta burn was followed by rain which washed a very large amount of soil off the valley sides and into the creek. We couldn’t quantify the soil loss, but the mud in the creek was up to the waist a week after the fire, and the Limestone Track causeway was blocked.
  2. The Loop track fire killed a significant number of big trees, and has resulted in rampant and dense regrowth of wattles and eucalypts. It’s now one of the few areas in the region where it’s almost impossible to walk any significant distance without a struggle. The vegetation load in this block is heavier than in adjoining unburned areas.

In both cases the outcomes were the result of fires that were arguably too hot; and in the case of the Tarilta fire, the serious soil loss was a direct result of stripping vegetation from steep valley sides a few days before forecast heavy rain.

I have an extensive collection of photos taken soon after the burns.

My questions are:

  1. What were the conclusions of post fire monitoring after the above two exercises [both as to ecological effects and fuel reduction]?
  2. What lessons have been drawn from the monitoring?
  3. How will the management of the upcoming burns be different [if they will]? I note, for example, that the two blocks contain significant areas of creekline vegetation and damp forest]

Sincerely,

Bernard Slattery

FOBIF Secretary

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We’ll let readers know when we get an answer.

 

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