Archive

Tag Archives: erosion control

Weeping Willow

“I believe that the presence of willows along streams in agricultural zones can be shown to be almost universally preferable to cleared streams in those zones. I would also suggest that even relatively low-disturbance eucalypt-Acacia dominated riparian vegetation may not have compelling benefits over willows under many circumstances.” (Wilson, 2007)

It would be fair to presume the comment above had been made by Peter Andrews, Natural Sequence Farming originator and outspoken champion for the much maligned willow. In fact, this statement came from Dr Michael Wilson, a stream ecologist who supervised numerous PhD and Masters research projects in Ballarat, Victoria, during the early 2000s, comparing streams flanked by willows; 100 year old, multi-strata, native regrowth, and cleared land with introduced pasture.

The full paper which is linked to at the bottom of this article goes into more detail, but here’s a summary from Wilson (2007) to give you the gist:

– On average, willow-lined streams had a higher retention of sediment (187t more/km) and organic matter (30t more/km) than the native forest.

– “Willow-mediated aggradation in these channels is converting them from incised channels to in-fill channels that are more characteristic of pre-European conditions”.

Litterfall of willow and native-reveg reaches had a similar annual distribution pattern due to the not-so-well-known summer dominant leaf drop habit of many Eucalypts.

– The annual weight of leaves, twigs, bark and flowers was very similar at the willow and native sites.

– With similar annual litterfall amount and distribution, coupled with dense shade patterns in the seasons of maximum productivity, the overall metabolism (and resulting biological oxygen demand) was also very similar.

– Root mats of willows were found to provide beneficial habitat to native fish in the absence of large woody debris.

– There was a disproportionately large association between pool-riffle sequences and willows, formed by the root mats of the willows.

“Pool-riffle sequences are extremely valuable habitat and for that reason alone it is worthwhile (maintaining willows). But it becomes even more valuable when it can contribute to ideas focused on restoring the whole of the floodplain complex in agricultural landscapes.”

“In all the streams we have studied, clearing willows will mobilise sediment, nutrients and organic matter, will make heterotrophic streams more autotrophic, will threaten habitat values for invertebrates and fish and will threaten pool-riffle sequences. Native vegetation planted where willows are cleared will take many decades if not hundreds of years to mature, for the canopy to close over and for significant limb fall to occur.”

View the full article:

Click here to view the full article, Willows: Weeds of Retention 

Wilson, M., 2007. Willows: Weeds of Retention. Proceedings of the 1st Natural Sequence Farming Workshop. ‘Natural Sequence Farming: Defining the Science and the Practice’, Hazell, Peter and Norris, Duane, Bungendore, NSW,  2007. http://www.nsfarming.com/workshop/

Advertisements

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.

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

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

For those who haven’t seen it, the following is a series of You-tube clips with Peter Andrews interviewed quite skilfully by Martin Royds at Baramul Stud. These clips, put together in 2007 by Paul Cochrane and the Natural Sequence Association, are one of the best overviews of Peter’s observations and hypothesis.  

Peter Andrews and Martin Royds discuss a leaky weir at the Natural Sequence Farming demonstration at Barramul Stud

Peter Andrews and Martin Royds discuss a leaky weir at the Natural Sequence Farming demonstration at Barramul Stud

(The following clips are placed in the same sequence as they appeared on the original DVD)

Peter Andrews at Baramul Stud – Introduction

Peter Andrews at Baramul Stud – Rock Walls

Peter Andrews at Baramul Stud – Weeds Pt1

Peter Andrews at Baramul Stud – Weeds Pt2

Peter Andrews at Baramul Stud – Deenergise

Peter Andrews at Baramul Stud – Floodplains

Peter Andrews at Baramul Stud – Wetlands 1

Peter Andrews at Baramul Stud – Wetlands 2

Peter Andrews at Baramul Stud – Tall Plants

Peter Andrews at Baramul Stud – Runnels

Peter Andrews at Baramul Stud – End of the flow

Peter Andrews at Baramul Stud – Erosion

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.

It’s hard to encapsulate all that is happening on Peter and Kate Marshall’s property Sunningdale in one go, but the following series of photos will give you a bit of a taste.

Peter is a pretty special guy. He’s got an understanding of the wider landscape processes which equals Peter Andrews, but he’s also a trained forester and is as widely read and knowledgable as anyone I have met. Add that combination to a desire to fix up some of the considerable degradation caused by his family in past generations and his wife Kate who is equally passionate and equally keen to heal their landscape and you have a pretty powerful combination.

Since commencing their work 22 years ago, the Marshall’s haven’t had it easy. Despite recognition from some of the top mycologists, hydrologists and foresters from here and abroad, within their own community they were largely ostracised early on, from members of the farming community on the one hand because they were seen as the thin edge of a green wedge, and from members of Landcare network on the other because they were using exotic species which Peter knew to have more potential in some land repair roles. Electric fences were cut, waterways were poisoned, authorities were called resulting in the threat of large fines, their children were bullied on the school bus and nuts were even taken off tractor wheels.

An amazing sign of the times is that on Friday night, the Marshall’s received a Champions of the Catchment award from the Upper Shoalhaven Landcare network. This award was introduced to recognise those who have done outstanding work in land repair which differs from the standard few lines of Eucalypts which usually fit the award criteria.

The next day, a tour of their place was conducted. “This is uplifting” was the way that one participant summed it up. Here’s a glance at a small portion of the uplifting work they they have carried out.

Peter leads off the tour, past the considerable biomass produced by Salix and Populus species after only 11 years of growth. These trees moderate the climate significantly through wind protection and transpiration effects.

Here, Salix plantings replicate the gallery forests which existed at the time of European settlement. Exotic species have been chosen due to the changed conditions making the original dominant species, Casuarina, very difficult to establish (heavier more acidic sediment, hare and rabbit predation, reduced frost protection due to complete deforestation and a dehydrated landscape).

Higher on the slope, Casuarinas have been easier to establish. Here, the ones in the background are being pruned for valuable furniture timber as are a wide range of other farm forestry species, suited to different sites on the property

Pinus radiata are pruned up for better quality timber. They were originally established due to their recognition by the tax man, but the focus has changed over time with the most valuable crop now below the ground, in the form of edible mushrooms such as slippery jack and saffron milk cap.

Here the group observes the understorey of ferns which has established beneath Blackwood and local tea tree. This site was dense with blackberries only 12 years without a tree in site. Seed filled brush mattresses of Leptospermum and mud encapsulated seed balls of Acacia were the main reveg techniques used.

Due to the repair of the main creek, the floodplain has rehydrated. These flats have been excavated to tap into the groundwater, creating a mosaic of water and earth, rich in biodiversity in some places…….

……..and planted out to useful agricultural crops in other places such as cricket bat timber or it would be perfect for ducks, fruit and veg if someone wishes to start an enterprise.

Fodder trees are grown in the hydrated landscape, the leaves and bark of which are devoured by goats and sheep. The left over woody biomass can either become material for building erosion-repairing fascines, or innoculated with saprophytic edible mushrooms like shitake.

A number of methods are used for establishing pole plantings while stock are in the paddock such as these tech-screwed tyres.

Wire mesh can also be used to protect trees from ringbarking

One of the Marshall’s most valuable and successful crops is the black truffle. This is a new orchard which has been established this season, using locally adapted oaks with excellent form for light penetration, and innoculated from a portion of their own truffle stock which they put aside this season.

These oaks were a pleasure to plant into the well prepared bed. This site was like concrete when Peter and Kate first purchased it, but after successive rips with the Keyline plough and a series of green manures, you couldn’t ask for a better start to life if you were a tap-rooted tree.

A number of stands of monopodial bamboos have been established for a variety of uses across the property including soil stabilisation, building material, fodder, biochar production and garden stakes which is an enterprise their daughter Rita runs.

What was once a bare walled gully is now a stabilised chain of ponds

This large world class wetland was created on another one of the hydrated flats, which now has black swans nesting. This particular piece of extensive work seems very altruistic, which it is based on the desire to reverse some of the degradation caused by each of Peter and Kate’s families over the generations, but this area of beautiful wetland habitat also offers significant hydration benefits to the surrounding landscape, with groundwater essentially backing up the slopes.

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

Article and images Copyright Cam Wilson, Earth Integral, 2012

Gravity’s always doing its best to take your fertility to the bottom of the hill. The following images explore a couple of ways to reverse this ever-present process, hopefully bringing a more positive slant to the old saying, “Pushing faecal matter uphill”.

This is a floodplain at Baramul stud, hydrated by the Natural Sequence Farming work completed by Peter Andrews. The pasture in the foreground is obviously lush and will provide some very decent feed, however, the tan coloured biomass in the background is equally interesting

This photo was taken standing on the back of a ute which Peter directed straight through this stand of Phragmites. The scale shows the considerable biomass produced as a result of the landscape hydration

Peter had said to me on many occasions that reeds make the best compost. So one day I gave it a go and what do you know, it did (and I’ve made my fair share). This was mainly cumbungi, but I’ve had similar results with Phragmites too.

A forage harvester, baling or in the gut of a cow are a few ways of moving the material up the landscape so that the compost is useful, as Peter Andrews mentions when talking about mulch farming in Back from the Brink.

Another plant that’s synonymous with water are willows, and the more fertile it is the better they grow.

Drop a willow near stock and see what happens. Sheep will strip every bit of bark off, as they have here on Peter and Kate Marshall’s property. Their sheep come to the sound of a chainsaw, as did the stock of a few people I have met, especially during the drought. That’s the time it’s valuable and research by the Kiwis has shown that with protein levels similar to lucerne, poplar and willow can maintain lambing rates during drought periods.

Because you’re close to water, the woody material which might otherwise get in the way can be used to fill in gullies and build more fascines and brush mattresses for erosion control.

With a feed value comparable to lucerne, poplars are another tree that grow on well-hydrated land, which stock will devour. The bark is especially high in trace minerals which are mined from deep down.

There are many varieties of poplars which can be used for different purposes, Populus trichocarpa being one which also provides useful timber.

Populus alba (silver poplar) is another, this stand provides good windbreak even when dormant, while the upright form minimises shading of pasture.

Pasture grows right up to the base of most poplars. The nutrients mined from deep down by the poplars are returned to the surface via leaf drop, enriching the soil beneath.

Browse blocks are utilised by the Kiwis which if grazed often enough don’t require felling with the chainsaw.

Using a number of tyres tech-screwed together, the Marshalls are able to establish poplars while the stock are still in the paddock. A large piece of cardboard eliminates grass competition during establishment. Tyres are removed when the tree is first pollarded.

Another use for a well hydrated floodplain is cricket bat willows. These ones are inoculated with white truffle, hence the oyster shells as a free, slow-release source of calcium.

Bamboo is another plant which does a fantastic job at stitching creek banks together, the foliage providing good fodder while the poles have a huge range of uses, one of which is a good cellular structure for biochar production.

And where do the stock head when they’ve got a gut full of all this? Up the hill of course, Nature’s anti-gravity nutrient transport service. Recognising this pattern, Martin Royds has realigned his fencing to facilitate this nutrient connection between watercourse (filter zone) and hilltop.

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 © Campbell Wilson, Earth Integral, 2012