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The following paddock layout offers a useful way of integrating trees into a grazing enterprise on sloping country. The aim of this approach is to minimise the impacts on production during the establishment phase, while offering significant benefits to both landscape and livestock once stock are reintroduced.

PADDOCK LAYOUT

Although shown here as a grid for illustration purposes, in a best case scenario the pattern is applied on a keyline cultivation layout, which offers extra water distribution benefits to the establishing trees. This particular example represents one of six paddocks, roughly equal in size on a small farm. A similar pattern can be adapted to a range of landscapes and different sized properties.

paddock layout

In short, the design incorporates a belt of trees which are planted across the top of the paddock, with water across the base. As seen in the image above, the paddock is divided into smaller cells by utilising temporary electric fencing, the width and quantity based on the desired number of grazing divisions on the property.

FENCING DIVISIONS

The temporary fence is run straight up and down the slope. Although perceived as an erosion risk by many at first, due to stock tracking up and down the slope, the short presence of animals and significant pasture rest & recovery offered by a time-controlled grazing approach means that this problem is largely avoided. On the contrary, significant benefits are offered by taking such an approach as outlined further down.

There are many options for electric fencing. The following end assembly of David Marsh’s is a simple  and cheap option for permanent electric fencing and KiwiTech fencing is the most elegant version of temporary fencing I’ve come across, allowing rapid assembly and disassembly while on a quad bike.

equ end assembly

Simple and cheap end assembly for permanent electric fencing. Design & Image: David Marsh

Kiwitech catalogue

WATER PLACEMENT

Dick Richardson has practiced Holistic Management grazing for almost as long as anyone and was one of the people credited in the original Holistic Management Handbook when they were detailing the how to’s. Dick, who comes from South Africa, now manages Hanamino, the Carbon Cocky award winning property of Charlie Arnott near Boorowa.

A few years ago, he told me that he was going to the effort of moving troughs from the top of the paddocks to the bottom. His reasoning was that although he understood the thought process behind why someone would put the water at the top of a paddock (to get nutrient in the form of dung transported to the highest point), it goes against the animal’s instincts. If you watch the cattle when they enter a new paddock, the highest point is often the last place they will look for water, meaning they are wasting effort and getting stressed, all of which affects production. Placing water where they expect to find it can pay dividends.

There are many options for portable water, but once again you can’t go too far past the consummate professional David Marsh.

water infrastructure

Left: Trough on skids, towed easily behind the 4 wheeler. Right: Quick couplings for emptying trough and connecting main line. Large diameter feed-pipe allows a smaller volume trough to be utilised resulting in less wastage and an easier time when shifting. Images: David Marsh

NUTRIENT CYCLING

Through the Millennia, there has been a common behavioural pattern in the wild herd: the open meadow offers sustenance and hydration, while the wooded hills offer a sheltered camp with a wide view, important for the ever hunted.

cattle under trees

By mimicking natural patterns, there are often advantages to be gained. Animal impact and pasture recovery offered by an Holistic Management grazing approach is a classic example. The age old pattern mentioned above, of drinking and feeding on the low ground and camping on the high ground is another which can be harnessed.

Gravity is one of entropy’s playing partners. The flowing path of water is the means by which the land is slowly eroded into the ocean. Life systems do their best to slow this process, and in the case of the herbivore, it sets gravity’s goal back a step or two.

Laden with a gut-full of food and water, the ruminant tramps up the hill seeking the afternoon shade. Arising after its rest, a parcel and a squirt of goodness are deposited on the ground, ensuring the ongoing health of the landscape below.

Although it’s on a smaller scale, the grazing strips running up and down the slope, with water at the base and woodland at the top, allow this timeless and fertility-renewing pattern to take place once again.

nutrient cycling

Single cell movement

Left: Stock feeding in the open paddock in the morning. Right: Lounging in the shade in the afternoon, transporting nutrients uphill.

A reconnection of valley floor to hilltop is one of the processes which both Paul Newell and Peter Andrews consider important, and has been implemented for that reason by Soils For Life Case Study participant Martin Royds.

PLANTING DENSITY & LAYOUT

The chosen tree planting density is another aim to mimic successful natural processes, in this case the grassy woodlands which existed in abundance at the time of Euro settlement. By many early explorers’ accounts, both pasture and soil were in excellent condition at the time.

Planting pattern2

Planting Pattern: (Click for a larger view)

Inspirational tree-planting grazier John Weatherstone of Lyndfield Park, has an entire paddock of Gleditsia triacanthos (Honey Locust) planted in this exact spacing (trees @ 7m, rows @ 14m).

HL & cattle 2

From a production perspective, this layout enables the trees to be separated from stock using a (semi) permanent electric fence, while the inter row can be cropped for the period of time that stock are excluded, making productive use of that land. When applied to sloping country, a keyline layout provides equidistant rows while also offering water harvesting benefits.

25 years after planting that paddock, John says, “It’s the best pasture on the property. Even if they didn’t produce any pods (the Honey Locust), if I could have every paddock planted out like that I would.”

HL & cattle 1

This statement is a result of John observing that highly palatable C3 grasses can benefit greatly from the dappled shade provided by the Gleditsia, staying greener for longer into the summer. Studies in the Southern Tablelands have shown that native pasture can also increase production when provided with shade.

Couple the pasture benefits with the fact that the trees offer shade and shelter to stock, thereby reducing stress and increasing production potential, as well as the multiple benefits offered by Gledisia (see below) and you can start to understand John’s glowing endorsement.

SPECIES

In this example, Gleditsia triacanthos inermis (Thornless honey locust) makes up 3/4 of the stand, while appropriate indigenous woodland species the rest.

The honey locust can provide multiple livestock and landscape benefits. Examples from the Lyndfield Park Story include:

  • Serve as a fire retardant
  • Deep rooted and are drought tolerant
  • Produce nutritious pods for stock fodder (up to 100km per mature tree per season. These pods have a nutritive value equal to oats grain or quality pasture and are produced with no extra costs once the trees are established)
  • Produce foliage which is also palatable to stock
  • Reduce the amount of water reaching the water table (thereby helping fight dry land salinity)
  • Provides dappled shade (see background) which maintains lush pasture longer into the summer
  • Suited to the open conditions of a woodland setting and allows pasture growth right up to the trunk
  • Late to leaf out and early to drop, maximising winter sun to C3 grasses beneath
  • Recycle nutrients (which had leached below the root zone of pasture plants, these are recycled back onto the soil surface through the foliage and pods)
  • Slow the increase in soil acidity
  • Produce timber (a dense hardwood with a number of uses)
  • Produce excellent honey
  • Enhance the view (it’s an attractive tree that is green in summer, turning gold in autumn)
  • Cycle deep nutrients which are returned to the surface as leaf litter

A word of warning on Gleditsia triacanthos: Honey Locust are a listed noxious weed in Queensland and in a climate that is more favourable than the Southern Tablelands, there is significant woody weed potential. If planted from seed, they will usually develop sharp 25mm thorns which can go through tyres. To avoid this situation, and ensure that each tree produces a significant quantity of nutritious pods, trees should be budded with material from a heavy bearing thornless variety (see below). 1 in 10 should be a male tree to ensure good pod set.

Budding Gleditsia

Budding seedlings using material from heavy bearing thornless varieties is essential to avoid tyre puncturing thorns in the paddock.

By including a portion of appropriate indigenous woodland species, this offers long term benefits to native biodiversity, with the associated benefits to production. (To avoid further pollution of successful genetics, aim to source seed from the local winners of the region.)

If you’re interested in design assistance for your property, feel free to get in touch

Disclaimer: While the information and images we publish are formulated in good faith, the contents do not take into account all the social, environmental and regulatory factors which need to be considered before putting that information into practice.  Accordingly, no person should rely on anything contained within as a substitute for specific professional advice.

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Article and Images © Cam Wilson, Earth Integral, 2013

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This post is a pictorial example of how to apply P.A. Yeomans’ Keyline-patterning for deep ripping, direct drilling or tree planting. It is meant to hopefully help clarify the subject a little for those who’d like to apply keyline patterning to their landscape in some respect, as I’ve seen and heard a number of incorrect applications and explanations floating around the internet. Nice to have a few clearer digital images too.

For a rundown on other aspects of Keyline design, a good starting point is to check out Abe Collins and Darren Doherty’s article, Keyline Mark IV, or visit Ken Yeomans site, http://www.keyline.com.au, where you can purchase Yeoman’s book, ‘Water for Every Farm’.

Finding the Keypoint and Keyline

If you would like to take advantage of the water distribution benefits offered by keyline pattern cultivation, identifying the keypoint and keyline are critical.

(Click on the first image to see a larger slideshow)

Application of Keyline patterning for:

Cultivation (i.e. Deep ripping, Pasture Cropping)

If you’ve decided to rip a paddock to help ease 100 years of compaction (having properly assessed the suitability of the landscape for this practice), or you’re direct drilling for a Pasture Crop, it doesn’t take a great deal more effort to do so on a keyline pattern. Here’s how I go about it.

Tree Mounds

Utilising keyline patterning for setting out tree rows can be very advantageous for any situation where equidistant rows are favourable, particularly where machinery is utilised in management of the inter-row.  There are two well known proponents of this method: The first is Darren Doherty, (many would have seen the image iconic image taken of the Tree Crop paddock on George Howson’s agroforestry property, Dalpura Farm), Mark Sheppard is another.

Here’s an example of how to set out a 4 lane tree belt using keyline patterning.

The same sort of approach can be taken for larger plantations, but there has to end up being some stub rows, or else the runs can get ridiculously steep and be erosion hazards in their own right.

Before you do any sort of hillside cultivation or earthworks which encourage more water to soak into a hillside, make sure you check the local environmental conditions carefully, particularly the presence of dispersive or slaking soils, saline seepage or the occurrence of slips in the local region. Entire hillsides of topsoil have been lost by ripping in the wrong place.

Disclaimer: Where water flow is concerned there are substantial risks involved. While the information and images we publish are formulated in good faith, with the intention of raising awareness of landscape rehydration processes, the contents do not take into account all the social, environmental and regulatory factors which need to be considered before putting that information into practice.  Accordingly, no person should rely on anything contained within as a substitute for specific professional advice.

Please visit and ‘Like’ our Facebook page to hear about future posts.

Article and Images © Cam Wilson, Earth Integral, 2013

Regrowth dry-sclerophyll forest like you see below is a common sight across the Southern Tablelands. It would be fair to estimate this growth at 10-15 years old, but in actual fact, the trees in this image at Mulloon Creek Natural Farms (MCNF) were all dated by an ANU researcher at 80 to 100. This forest is stagnant and moribund.

It’s a common story: hillsides were ringbarked, grazed and burnt repeatedly by early pastoralists of the region, until it no longer paid to do so (i.e., the decent soil was gone). With an even race for the light, the young Eucalypts take off (in this case the epicormic regrowth from the last ringbarking effort), but when the canopies of the closely spaced trees touch, they basically hit pause, limited by competition for nutrients, moisture and light.

moribund forest

Unless you’ve got the right species and are after coppiced poles, this result isn’t good from a number of perspectives, whether it’s sawlog production (insufficient size), habitat (lack of hollows and minimal niches), or soil conservation (exclusion of grass and shrub groundcover) to name a few.

Research carried out by students of ANU Professor John Field showed the effects of various treatments (thinning, exclusion, disturbance & fertiliser) on the health of the forest (stand basal area, and diversity of species). See the abstract of their findings at the bottom of this post.

These studies have informed the guidelines for carrying out Private Native Forestry (PNF). This legislation provides a sensible set of guidelines to forest management which allows a good balance between production and ecology.

Even low quality timber from a forest like this can be put to some good uses (I’m particularly interested in erosion control uses, but poles, posts, firewood, mushroom cultivation, mulch, & charcoal are a few obvious other uses) while at the same time, the health of the forest as a whole can be improved, providing environmental benefits to the landscape below and potentially the surrounding climate.

The PNF regulations allow this work to be carried out without the risk of massive fines, and a PNF Property Vegetation Plan can be easily obtained (find out more here). The following are a series of images taken at Nanima Gold, the property of Mike and Denise McKenzie where we’re carrying out some gully repair work.

Pre-felling, trees are marked as either existing habitat or recruitment trees under the Private Native Forestry guidelines. Trees are thinned to a given basal area depending on the forest type.

Pre-felling, trees are marked as either existing habitat or recruitment trees under the Private Native Forestry guidelines. Trees are thinned to a given basal area depending on the forest type.

The felled logs are lopped to a suitable size for whatever your intended use. In this case, the majority of the poles were carted down to a gully where we are building fascines as part of a Landcare sponsored erosion control project at Nanima Gold. (The fascines are a topic for another post.)

contour brush

Following the removal of any logs over 80-100mm, the remaining brush can be thrown five metres either side, creating 10m wide contours which snake around the landscape (as a quick way to mark rough contours along a slope: stand downhill, hold your arms out straight, stick your thumbs up and you’d be surprised how accurately you can find your next mark).

The brush contours become more important the barer the understorey, such as in this older project I built for The Mulloon Institute.

Flash runoff on this hillside has carried soil and organic material downhill

In that particularly degraded piece of forest, the bare path in the centre of this photo was caused by flash runoff, carrying soil and organic material downhill.

After one decent downpour, this brush contour has collected a significant amount of soil and organic debris

After one decent downpour, this brush contour collected a significant amount of soil and organic debris, acting like a hillside leaky weir.

When you create conditions in which worms are happy inside a dead forest like this, you know you're on a reasonable path

When you create conditions in which worms are happy inside a dead forest like this, you know there’s a reasonable chance you’re on the right track. I wish I could press fast forward and see what the result of these brush contours is in 50 years time.

More studies have shown the formation of hydrophobic (water repellant) soils under some Eucalypts. This is believed to be caused in part by mycorrhizal fungi, which help to direct moisture towards the roots of the associated Eucalypt, while creating unfavourable conditions for establishment of any competition.

The following pictures were taken after 80mm of rain, illustrating the extreme hydrophobicity in the Eucalyptus rossii forest at MCNF, pictured above (click on an image for a larger view).

Therefore, in these conditions the seeds of understorey grasses and shrubs either don’t have the moisture to trigger germination in the first place, or if they do germinate, they have to fight through 50mm of bone dry material to get any moisture. Hence, the relatively bare forest floor in the pictures above.

With this in mind, an extra layer of disturbance which may be useful in promoting under storey establishment is the short term integration of pigs, their rooting action helping to break up the fungal mats and reduce competition while grasses and ground covers establish (the pigs having moved on of course).

Disclaimer: To avoid hefty fines, ensure you follow relevant local legislation. No person should rely on anything contained within as a substitute for specific professional advice.

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Article and Images © Cam Wilson, Earth Integral, 2013

Private Native Forests, Southern Tablelands of NSW: Silvicultural Treatments Revisited

Simon Roberts, Chris Chartres, John Field & Chris McElhinny, 2006.

Forestry Program, SRES, ANU, ACT.

Abstract

Regrowth stands of dry sclerophyll forest extend from Central Victoria through the NSW Southern Tablelands to Southern Queensland (Field and Banks 1999). The ‘Mulloon Creek’ property, 15 km east of Bungendore in NSW is representative of this forest type. In the past, the property was extensively cleared (1890’s, 1920’s and 1950’s) and grazed (until the early 1980’s), and now supports a regrowth forest possessing a degraded structure compared to its predicted pre-European state.

In 1991, Field and Banks (and others) established a silvicultural experiment to investigate the effects of different treatments on this forest. Their preliminary findings (Field and Banks 1999) indicated treatments such as thinning and burning had little effect on overstorey or understorey growth, however fencing to exclude grazing by native and feral herbivores promoted the establishment and growth of understorey plants. The long term results, however, demonstrate that these silvicultural treatments are effective management techniques.

One-way analysis of each treatment on the overstorey (statistically in isolation of each other) reveals that thinning and burning both had significant effects on Relative Growth Rates (%BA Increment/Yr). The effect of thinning on the treatments had the most significant impact on tree growth. Over the twelve year period however, the burnt treatment had a significantly greater percentage annual basal area increment. Unlike thinning or burning, the effect on relative growth rate of exclusion fencing is not significantly different. Similarly to fencing, fertiliser had very little effect on relative growth rates of trees at the end of seven years since the application.

The understorey results were evaluated in a similar way. Only the fences treatment had a significantly higher mean richness of perennial species (21) compared to the unfenced treatment which had only 14.5 species. Fencing to exclude grazing animals has long been regarded as critical for the regeneration of native understorey plants.

Reference

Field, J.B., Banks, J.C.G., (1999). Effects of Silvicultural Treatments on Growth Rates of Trees and Diversity of Understorey in a Private Dry Sclerophyll Forest, Southern Tablelands, NSW. IFA conference “Practicing Forestry Today”, Hobart

Below are some photos and videos taken along a transect of the floodplain on Peter and Kate Marshall’s property. I hope you enjoy these images (taken 36 hrs after a 180mm overnight event), with the creek running crystal clear and spread out across the floodplain on Sunningdale.

To put what you’re seeing in context, most other watercourses in the region are restricted predominantly to the channel due to the erosion and incision caused by past land management practices. Although man-made, the hydrology in this landscape is much closer to the way it operated pre Euro settlement, in an intact chain of ponds or swampy meadow system. The noise of the frogs in the videos is testament to the significant aquatic and wetland habitat which has also been created.

Photo locations taken across a transect of the floodplain at Sunningdale

Locations of photos taken across a transect of the floodplain at Sunningdale. (For some scale, the image is 350m wide, and the main channel located at the meandering tree-line, flowing from bottom to top).

To flick through a larger slideshow of the images, click on any of the thumbnails below

Short video locations taken across a transect of the floodplain at Sunningdale

Locations of short videos taken across a transect of the floodplain at Sunningdale

Finally, another interesting little clip is of the ground literally bubbling as the subsurface flow rehydrates the gravel and sediments below the surface. This stored moisture benefits the land’s production and drought proofing resilience, while also providing a more sustained base-flow to the landscape below.

See the articles tagged as Key floodplain processes for more information on what is being achieved from a landscape perspective.

Please visit and ‘Like’ our Facebook page to hear about future posts.

Disclaimer: Where water flow is concerned there are substantial risks involved. While the information and images we publish are formulated in good faith, with the intention of raising awareness of landscape rehydration processes, the contents do not take into account all the social, environmental and regulatory factors which need to be considered before putting that information into practice.  Accordingly, no person should rely on anything contained within as a substitute for specific professional advice.

Article and Images © Cam Wilson, Earth Integral, 2013

A stroll, post flood

A stroll, post flood

Increasing atmospheric CO2 levels during the industrial age have gained a lot of exposure in the link with a changing climate. An area which has received far less attention are the significant changes to both local and global water cycles and vegetation patterns during the same period of time.

Water For the Recovery of the Climate – A New Water Paradigm (Kravcik et al, 2007) explores the science behind the very direct links between vegetation and both temperature and precipitation.

It’s a read I highly recommend and it can be downloaded by clicking on the title in the paragraph above. So that the time-poor can get the gist, I have included a number of the diagrams from the paper in a slideshow at the bottom of this article.

Here’s a very simple summary as well:

1) At any given time or place on the planet, there’s a certain amount of solar energy hitting the surface of the earth. That energy can be put to two very different uses.

The distribution of solar energy on drained land and on a landscape saturated with water (Kravcik et al, 2007)

At one extreme, a bare soil (or concrete, steel, etc), the majority of that energy is absorbed and re-radiated as (sensible) heat, warming the local environment.

At the other extreme, a saturated wetland, the majority of that energy is utilised by plants for photosynthesis, with the resulting transpiration drawing (latent) heat from the surrounding area.

So the sun’s energy is used to either power a landscape-scale radiant heater (above left) or a landscape-scale evaporative air conditioner (above right).

2) Of the average 720mm of precipitation that falls on land, the input from the sea is about 310 mm (the large water cycle). Hence, the land provides the larger part of its own precipitation (410 mm) from its own land-based evaporation (the small water cycle).

Small water cycle

Kravcik et al (2007)

Therefore, a drained and dehydrated landscape, coinciding with relatively shallow rooted plants (ie conventional western agriculture) ultimately means less rain over the land, in a (not so) positive feedback loop.

A landscape which is primed to accept whatever rainfall or overland flow that arrives and to send that moisture through actively growing plants, means more rain over the land in a (more) positive feedback loop.

More soil moisture = more evapotranspiration = more precipitation = more soil moisture etc

The radiant heater mentioned previously means less rain; the evaporative air conditioner, more.

In closing, a couple of short paragraphs from the paper:

“The renewal of the domination of the small water cycle, which is advantageous for humanity, vegetation and the land, depends on the renewal of the functional plant cover of a territory and water surfaces in a country.”

“With sensible management of water and vegetation we can curb climatic change on the local level; if we can act in the same way across larger areas, perhaps we can expect a tempering of global climate change.”

We’re in the business of landscape-scale air conditioners, so if you’re interested, please get in touch. Or, visit and ‘Like’ our Facebook page to hear about future posts.

 

Reference:

Kravcik M., Pokorny J., Kohutiar J., Kovac M., Toth, E, 2007. Water For the Recovery of the Climate – A New Water Paradigm

Click here to download a pdf of the paper

Click on the images for a slideshow of the diagrams from the paper.

A newly planted 5 ha mixed-Oak and hazel, truffle inoculated dehesa.

Building on the success of their well-respected business Terra Preta Truffles, the Marshalls have planted a further 5 ha of truffle orchard this season (click here for a virtual tour of Sunningdale). The system includes a wide variety of oaks, sourced from the Canberra region, interplanted with hazels which provide a shorter term truffle return. Under the guidance of top mycologists, the trees have been propagated and inoculated on farm this time around, partly because of the availability of truffles for inoculant, but also due to the very mediocre (and no-doubt concerning for many) results in the findings of a recent ANU study on the Australian truffle nursery industry.

Click on one of the images below for a slideshow of how we went about planting each of the valuable trees in ‘Mari’s Montado’ (named after Mari Korhonen who spent six months with the Marshalls last year and planted a good portion of this paddock).

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Copyright Cam Wilson, Earth Integral, 2012

In some locations with deeply incised gullies, both the goal of channel-floodplain reconnection and the goal of lateral floodplain rehydration are pretty much out of the question, at least in any way that will benefit most species on the floodplain (other than deep rooted trees).

One such example is the Natural Sequence Farming demonstration on the home farm at Mulloon Creek Natural Farms. To achieve either of the above goals would require a large engineered structure, which in a named perennial stream doesn’t sit too well with the existing regulations (extraction is achievable but would require a costly irrigation licence).

Currently, despite regulation exemptions which allowed some of the structures to already be quite large, the water level still remains 4-7m below much of the floodplain. This results in little benefit to the vegetation on the floodplain, but I believe the works have still been a success in a number of ways, one of which is setting the natural repair processes in action. (See the Mulloon Institute website for details of the research that’s been conducted)

Even during a 1 in 50 year rain event, the flow remains well below the surrounding floodplain

The locations where chains of ponds and swampy meadows existed in abundance at the time of Euro settlement, such as Mulloon Creek, are known as ‘cut and fill landscapes’.

The ‘fill’ phase referred to in ‘cut and fill’ is relatively well understood. As Peter Andrews has popularised, dense wetland vegetation choked the discontinuous channels, slowing the water flow, trapping sediment and then binding it within vertically growing root mats.

The ‘cut’ phase isn’t quite so well known. Although these systems could remain stable for thousands of years, they weren’t permanent. A natural disturbance could set a period of degradation into action, with erosion gullies cutting through the floodplain sediments. Eventually, the ‘cut’ phase stabilised and the ‘fill’ process would begin again (Johnston and Brierley, 2006).

This rebuilding phase has in fact begun in some places. Zierholz et al (2001) wrote a great paper on the process, outlining the natural establishment of instream wetlands. In some places, their study found that dense reedbeds had accumulated up to 20 years worth of sediment from the associated catchment. That is, the floor of the gully is aggrading, nutrients and sediment are being held, valuable wetland is being created, erosion is being prevented, and the main reason: lots of reeds have established.

Photo of a typical instream wetland. Up to 20 years of sediment has been trapped and stored in some tributaries in the Jugiong creek catchment, NSW (Zierholz et al. 2001)

The fine sediment has accumulated since the establishment of the instream wetlands. (Zierholz et al. 2001)

On Mulloon Creek, there are sections which before the NSF works were completed were either cut down to bedrock or basically gravel deserts, and had been that way since the degradation began, which likely occured in the early to mid 19th Century (Hazel et al. 2003). Those same sections now look very similar to the photo from the paper above.

Instream wetland forming as a result of Peter Andrews’ Natural Sequence Farming demonstration at Mulloon Creek Natural Farms. This site was down to bedrock before the works began.

What’s been the trigger? As they say, just add water:

A side profile of an incised gully, predominantly dry in between rain events

Unimpeded flow carries sediment through the incised channel

A grade control structure (or leaky weir) is constructed, causing a pool to form behind

The main flow slows as it hits the water backed up by the structure, causing sediment to deposit (halve the slope and your halve the energy)

Steel post markers put in place by Charlie Maslin on ‘Gunningrah’ show that 1.5m of sediment has been deposited at the rear of this pool. As a result of the new bar, a pool is forming in the tributary to the left of the photo

A new bar begins to form, holding moisture for longer and allowing stabilising vegetation to establish.

This bar which has formed as a result of Dimity Davy’s structure downstream has begun to stabilise with vegetation. With the exclusion of stock, Cumbungi (Typha) and Phragmites reeds are beginning to establish.

In time, retained moisture and sediment allows riparian vegetation to establish

Dense reeds are establishing at Peter’s Pond at the Mulloon Creek demonstration as a result of the pond formed by Peter’s (leaky) weir

Reeds themselves trap sediment and moisture and the bed of the channel begins to aggrade (opposite of degrade)

Universal process: Add a ‘structure’ to a gutter (a bit of spilt asphalt) and a few weeds growing from cracks and it even happens there.

Fornicating worms in the same gutter

As Craig Sponholtz of Dryland Solutions in New Mexico puts it, “This type of restoration work uses earthworks to create a foothold for natural processes. The structures then get assimilated into the ecosystem as natural healing processes take over.”

That pretty much sums up our work, so if you’re interested in helping to set nature’s repair processes into action, please contact us to discuss our design, consultancy and implementation options.

Please visit and ‘Like’ our Facebook page to hear about future posts.

Disclaimer: Where water flow is concerned there are substantial risks involved. While the information and images we publish are formulated in good faith, with the intention of raising awareness of landscape rehydration processes, the contents do not take into account all the social, environmental and regulatory factors which need to be considered before putting that information into practice.  Accordingly, no person should rely on anything contained within as a substitute for specific professional advice.

Article and Images © Cam Wilson, Earth Integral, 2012

References

Hazell, D., Osborne, W. and Lindemayer, D. 2003. Impact of post-European stream change on frog habitat: southeastern Australia. Biodiversity and Conservation, 12: 301–320, 2003.

Johnston, P. and Brierley, G. 2006. Late Quaternary river evolution of floodplain pockets along Mulloon Creek, New South Wales, Australia. The Holocene 16 (5): 661-674.\

Zierholz, C., Prosser, I., Fogarty, P. and Rustomji, P. 2001. In-stream wetlands and their significance for channel filling and the catchment sediment budget, Jugiong Creek, New South Wales. Geomorphology, 38221-235.