Tag Archives: erosion

Year of Fire: Annual Report 2020

27 Monday Jan 2020

Posted by in ecology, planning, regeneration, trees, waterways

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A melted tree guard shrink wraps a seedling after a fire move through part of the property in January 2019.

2019 began and ended in fire. In early January, some errant fireworks set off by passers-by landed in one of our front paddocks, burning across a couple of hectares of our property. We were lucky. There was little wind, and it was quickly noticed and contained by our amazing neighbours and the CFS. Meanwhile, in Tasmania, fires ripped through the forests, and by spring and early summer, vast tracts of the east coast and Kangaroo Island were catastrophically aflame once again. While we’ve escaped the drought and bushfires that have gripped so much of the continent, these phenomena have served to focus our goals and aspirations in 2019. It’s been a year of learning as we work towards a more regenerative approach: ultimately building soil and harvesting water and carbon in the landscape.

2019 had the dubious distinction of being Australia’s hottest and driest year on record. It got pretty warm in the shed.

Learning
Our regenerative aspirations have been focused by some outstanding events this year. In June, we attended the Deep Winter Agrarian Gathering in Willunga, drawing together 150 aspiring and established regenerative farmers from around Australia to share skills and ideas. Former CSIRO microbiologist and climate scientist Walter Jehne set the tone with a rousing and inspirational keynote on restoring natural processes through agriculture to cool the climate.

The Food Forest’s Annemarie Brookman with Gardening Australia’s Costa Georgiadis at Deep Winter, Willunga.

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Winter work: erosion control in dispersive soils

11 Sunday Aug 2019

Posted by in diy, ecology, regeneration, waterways

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Some of the challenges of our landscape regeneration efforts have been both working to restore eroded badlands in some parts of the property, as well as to arrest continuing erosion. To make matters more complex, some sections of the property have “dispersive” subsoil. While the topsoil is relatively stable, when the subsoil becomes saturated it dissolves and begins to move, hollowing out tunnels beneath the surface that ultimately collapse into sinkholes, and eventually gullies. Of course, because it’s all happening underground, tracking or predicting which areas are vulnerable, or already cavernous is tricky.

Over the last seven years, we’ve been gradually working our way around the property installing erosion control structures, based on the work of permaculture-based landscape restoration folk like Craig Sponholtz and Bill Zeedyk. Hailing from the dry southwest of North America, Sponholtz and Zeedyk advocate applying small and slow interventions that use local materials to slow water flows and gradually heal erosion. In the permaculture spirit of viewing problems as solutions, our junk-filled erosion gullies have provided a seemingly inexhaustible supply of demolition rubble, concrete chunks and segments of brick walls that are ideal material for these structures.

This headcut just keeps moving, despite the perennial grasses and good ground cover.

One of the sections that we’ve avoided is a notorious headcut that our DIY soil tests showed us boasted slaking soil that disintegrates when moist and subsoil that was also more saline than other locations around the farm. With saline subsoil, most plants wanted to avoid getting their stabilising roots down. Tree-planting was also fraught, survival rates in the saline subsoil and cracking grey topsoil were low and  the very process of digging a small hole for a seedling can be enough to expose the subsoil so that next time there was a downpour, a sinkhole would open and swallow the seedling, tree guard and all. With the headcut moving about a metre a year and also widening, we thought it was time to get stuck in. At the very least, we’ve discovered that doing something is better than doing nothing and the act of getting in there and digging around allows for more accurate monitoring and effective intervention. Continue reading →

Yarnauwi Treefest 2019

10 Monday Jun 2019

Posted by in diy, ecology, regeneration, trees, waterways

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A serial tree-planter manages to synchronise his outfit with the colouring of Eucalyptus occidentalis.

A couple of days before this year’s tree planting, I rang our friend and regular tree-planter Jeremy, and told him that three out of four family members were sick with the flu and we were thinking of cancelling this year’s planting weekend. He didn’t accept that proposal, effectively telling us that tree planting would happen regardless of our involvement, that between his family and another they would take care of catering, rally the volunteers and get the trees in the ground.

It has always been an aspiration of ours that the farm might offer a place for people to be able to develop connection with the landscape through collaboration on land-based projects – “where people and the landscape can restore each other”. I hope that Jeremy’s response, and the support of our friends and community over the last seven years of tree-planting is an indication of this aspiration in development. In this spirit, this year we were also delighted to host regenerative side projects such as Steven Hoepfner’s seed ball regeneration experiment, and provide a waterway for Sue and David Speck’s sedges, and a forever home for Greg Wood’s trees.

Steven’s seed ball project: local provenance bundles of seed and nutrients distributed across revegetation zones to germinate when the conditions are right.

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Treasures from the deep: more curated gully junk

31 Sunday Mar 2019

Posted by in ecology, history, waterways

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Despite a long silence from us, there’s still lots going on at Yarnauwi, not least our ongoing attempt to clean up historic dumping in our erosion gullies. We feel like we’re closing in on the last 30 metres or so of junk to clear and now we’re so close to finishing it can sometimes be difficult maintaining motivation! While most of the material remaining is steel or demolition rubble, both of which we recycle or repurpose, there are still pockets of wonder in the form of various plastic domestic items. Happily, the plantings established in previously cleared areas are now well-established and working to stablise the exposed gully walls as well as restore them as habitat and an ephemeral waterway. We’ll write with more updates soon, but in the meantime, enjoy these treasures from the deep.

Specimen #51: Plastic clown launcher from a “Dandina Sky Dancer”, released in 1995. This particular clown is from the Italian Masque series of the toy. Intact toys from this series in original packaging are available online for a mere US$75.00. (Thank you to Pascelle for the ID, see comments below)

Specimen #52: Wobbling bear in winter attire.

Specimen #53: Battery operated toy train.

Specimen #54: Lightly soiled Boggle Junior console, dating from around 1988. Some cosmetic wear and tear.

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Not ‘if’, but ‘when’: planning for fire

07 Monday Jan 2019

Posted by in ecology, planning, regeneration, trees

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Melted tree guard on a eucalyptus seedling.

A few evenings ago, someone set off fireworks on the road beside our property. Embers from the fireworks landed in the grass on the property boundary and quickly took, spreading through the dry summer grass along the fence and down a drainage line. Thankfully, our neighbours quickly noticed and set to work with their own fire unit while awaiting the arrival of the police and Country Fire Service. The blaze was contained with minimal damage, but it’s stimulated us to revisit our property plans and consider how we’re designing for the inevitability of fire.

Scorched earth and singed trees.

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Yarnauwi Annual Report 2016

29 Thursday Dec 2016

Posted by in ecology, planning, regeneration

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In birthday cards I often wish the recipient a coming year of “the right kind of challenge”, optimistically suggesting it will herald positive growth and empowerment through problem-solving and negotiation. This year, I got a taste of my own medicine, with a winter of biblical proportions just the beginning of the challenges.

November marks four years since we began the Yarnauwi project. Four years of attempting to regenerate the property to our optimistic standards on the weekends, of packing and unpacking the car, of ferrying and entertaining one, then two, small children, of revegetating, managing erosion, managing pasture, managing water, managing livestock, managing weeds and managing the legacy of past land managers. These are all admirable, ambitious intentions, and what we’ve achieved has only been possible through the support and enthusiasm of our community of neighbours, friends and family. Continue reading →

The Wet Season 2016

06 Sunday Nov 2016

Posted by in ecology, livestock, trees, waterways

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The first big storm saw the dam fill and rivers broaden to ten times their normal size for an afternoon. A neighbour’s creek crossing dissolved in the flow, the rock and rubble broadcast along the river bottom. The second big storm saw our rainwater tank, still awaiting a shed to fill it, lifted vertically from its nest of stardroppers, vaulting a tractor and four or five fences before being swept off in the swollen waters of the Anacotilla River, carried across two properties and wedged under a red gum. The third storm came with days of warnings, threats of winds over 120km/h and rainfall to rival all of the previous deluges. It left all of South Australia without electricity, the farm a sucking, gurgling swamp, and me walking home through a darkened, scrambling city.

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Mist in the valleys

It’s been a demanding few months on the farm. The persistent moisture has made the ground unworkable, most of the farm inaccessible except on foot and the weather generally hostile to both our motivation and ability to do anything useful. The vast quantities of rain we’ve received however, have meant that moisture has permeated deep into the subsoil, so we console ourselves with the hope that as the weather warms, our tree plantings (including those from earlier this winter) will rocket skywards. Continue reading →

Winter and the One Rock Dams: erosion control after the rain

24 Sunday Jul 2016

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Rain, and a full dam.

By late July this year we’ve already exceeded our entire rainfall for 2015, and for now, the rain shows no signs of abating. This is fantastic news for our revegetation efforts, and our dam is now almost full for the first time in two years. With heavy rains – we managed to top 100mm (4 inches) in a single day – it’s also a chance to test the effectiveness of the erosion control strategies we’ve employed.

With significant erosion in some key areas of the property, we’ve worked to adapt erosion control strategies such as those practised by Bill Zeedyk and Craig Sponholtz (see April’s Waterway Restoration workshop/working bee and our Resources page for more information). In particular, we’ve constructed Zuni bowls, for arresting headcuts, and One Rock Dams, to slow water flow, catch sediment and gradually lift the floor of erosion gullies. After the recent deluge, we toured the works to see how we went. The Zuni bowls have had mixed success: those in relative stable locations have been effective, those in dispersive soils have been unpredictable. The One Rock Dams (ORDs) have been generally successful, if swamped by sediment!

The impact of 100mm of rain in one day is significant: exposed areas lose significant amounts of soil (some areas of gully floor had almost 30cm of freshly deposited sediment), and areas of dispersive soil go berserk, collapsing in all directions. For some of these areas, we’re continually seeking further advice, but for those we can manage, we monitor and tweak over time, and try to “let the water do the work” in healing the landscape.

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Matching trees to tricky spots

25 Saturday Jun 2016

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Eucalyptus occidentalis, a hardy, salinity and waterlogging tolerant timber and bee forage WA species, putting on new growth despite a dry year.

For the first couple of years of tree planting, we adopted a pretty haphazard approach, planting a bit of everything everywhere, and waiting to see what would stick. It took only a couple of months to highlight which areas offered the conditions for revegetation at a respectable pace, and which did not. Some patches only appeared to support certain species, others seemed to support nothing at all. The challenge has been to work out why. For enthusiastic amateurs like us, the working out comes through plenty of observation, plenty of reading and plenty of research.

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One persistently hostile area of the farm offers saline, slaking, seasonally waterlogged clay with tunneling and cracks you could lose a child down.

For some areas on our farm, vegetation is a valuable indicator, plants like sea barley grass (Hordeum marinum) suggests mild salinity, and, in our case, seasonal waterlogging. In others, aspect and soil type present challenges. Three years of tree planting and walks through local bushland have also given us a sense of which local species might suit which locations. We keep trying new configurations in the same places, and also try to mimic the natural process of succession by planting hardy pioneers first, then waiting for them to establish shelter and canopy before adding others. As the balance of the landscape has changed through clearing, cultivation and the associated effects of erosion, shifting water tables and changes in nutrients and soil biology, many of the species that may have dominated a couple of centuries ago no longer tolerate certain areas of the block. Likewise, some areas that may have been conducive to vegetation when woodland was already present, once cleared, they seem to be hostile to its re-establishment: for example, a north-facing corridor of grey, cracking clay that has resisted our affections for two years now. Continue reading →

Winter active

31 Tuesday May 2016

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Blue gum (Eucalyptus leucoxylon) seedlings ready for planting.

Before Yarnauwi, we never really appreciated winter. Now, through the long dry season, we find ourselves yearning for a chill edge to the wind, the moisture in the grass, and skies of dark clouds. We’ve tried to plan our year to mimic the lives of so many of the organisms that occupy our landscape: in the hot, dry times, we go into maintenance mode, watching and waiting for the first rains before we spring into action again. With the greening of the landscape, it’s all on: tree-planting has begun, shed sites are levelled, the grass grows. In winter, the kangaroos converge in clans numbering hundreds, displaced from the pasture, they lounge among the seedlings in the reveg areas while we look on nervously.

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Joel and Annika work on a rock dam to arrest erosion on a boundary before the rains hit.

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And then the rains hit.

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