Photographs © Craig Mackintosh
Inter-row Eucalyptus saligna (Sydney blue
gum) & Casuarina cunninghamiana
(river she oak) planted in 2000
I recently had opportunity to visit a Permaculture site called ‘Dalpura Farm’, near Geelong, outside of Melbourne. Although (or perhaps, because) designed by Darren Doherty, the very well known Permaculture designer and teacher, it was dramatically different than your average Permaculture site. Rather than an urban edible garden, or a fruit-/veg-/livestock-oriented rural block, this 140-acre property was all about trees.
It’s an experimental agro-forestry project, aimed at finding the best way to produce a range of commercial products and ecological benefits from trees, with timber production being the primary focus.
I contacted Darren, the designer, and George Howson, the owner of the property, to see what it was all about.
Craig Mackintosh: With Peak Oil issues right at our door, sales of seeds and potting mix are going through the roof. But, with the ‘Dalpura Farm’ project, you seem to be saying we should be thinking beyond just cauliflowers and cabbages. Wood, prior to the industrial revolution, was always the main source of fuel for humanity. Is any of the motivation behind this particular project connected with future resource constraints?
Darren Doherty: Well the focus at Dalpura was from the start influenced by the fact that the developer was an absentee landholder and we had tenants in until just a few years ago…. They showed only a little interest in what we were trying to ultimately achieve so you could say we started at the back gate and have been working towards the back door ever since. Our main priorities were to develop a site that could achieve multiple outcomes, with a particular focus on valuable managed timber plantations and silvopastoral systems following Keyline™ Design methods, where we treat the whole site as one big water catchment rather than concentrate on using technologies such as swales as many in Permaculture do.
The soil is the cheapest place to store water and we have lifted the SOC level on these very poor, laterised Tertiary Gravels (the region’s largest gravel mine is right next door and Dalpura shares its geology!) from about 2% when we started up to around 6%+ which has made a huge difference to the performance of the various plantings on the site, and therefore the water & mineral cycles have improved radically over the whole site where we have done work. This is despite the fact that rainfall has been very much less than average over the period since we started back in 1996.
The world is short of topsoil and that is the foundation of everything and as I like to say, ‘…..we have to be Blue, before we can be Green or Black….’, meaning we need water (blue) before we can photosynthesis (green) and therefore build carbon (black). I have never been one who has focused on resource constraints as such, rather we have always developed low cost solid state systems that would ultimate yield in any situation.
New revegetation planting (2009)
George Howson: While the primary goal of the forestry plantations is to produce high quality, feature grade timber for furniture and joinery, the systems are designed with multiple products and purposes in mind. I had used a number of native Australian timbers as features in a range of energy-efficient, inner-city housing developments in Geelong in the early 1990s, and was keen to grow the timbers myself and promote their attributes. At the time I formulated the brief, and Darren designed the initial systems, the aesthetic qualities of Australian timbers were generally under-appreciated, and I saw an opportunity to do something about it on a very small scale. I was also predicating the future economic and other values on the likelihood that timber supplies from native forests will be progressively locked up, and that small scale farm forestry is a better way forward in both social and ecological terms.
Other intended products from our trees at ‘Dalpura Farm’ include harvesting seed; fire-wood; poles from thinnings for orchard fencing and garden structures; and the possible production of shiitake mushrooms on farm-grown logs. Stock fodder systems are also a core element in future planning, with integrated grazing along Holisitic Management lines an enterprise currently being explored.
Wetland Crossing Dam, a concept developed by Darren Doherty as an alternative to
conventional concrete culvert/end wall. Nothing planted: all self-established
vegetation. Built by Paul ‘Ringo’ Kean in 1.5hours with a D5 in 2007. Acacia
implexa (lightwood) & Eucalyptus leucoxylon (yellow gum) complex (1998)
CM: I noticed the trees were planted in swale-type formations, except angling up from valleys onto the slopes rather than running on contour. Could you give us more details on this, and tell us the reasoning behind such a design?
DD: There is not a swale on the property. I have never been much for swales in this part of the world or many other places where I can use the geometry of Keyline™. I understand and use swales where I feel they are an appropriate patterning, but find that in plantation (or orchard) settings the use of the geometry of topographic contours is awfully problematic due in large part to the lack of equidistance between contours, leaving turns to often occur within the planting itself: this is a pain to say the least when it comes to management operations.
The lack of equidistance of contours also gives you the following issues:
- Can’t fit as many units into a given area
- Can’t obtain tree offset patterning so important in tree system design
- Much more difficult to set out the design: with Keyline™ geometry you mark one line and then do a series of 90° offsets off of the 1st line.
- The drift of runoff (on the rare occasion it now happens) towards the ridge in our system at Dalpura is an application of the Keyline™ geometry. The rationale behind the mounds themselves were to increase the internal drainage characteristics of the soils together with water harvesting. These mounds were constructed using two opposing discs attached to the Yeomans Keyline™ Plow which was subsoiling at the same time.
Sometimes I sense that people use & recommend contours because it is an easily transferred technology, whereas Keyline™ geometry requires a much more detailed understanding of topography that is easily and very often confused. Our application of Keyline™ geometry over the years has become very complex down the point where we are able to create completely symmetrical layouts whilst working on curves. This is difficult to do and requires the following:
- Electronic topographic survey (ie. Total Station) of the landscape
- CAD layout planning
- Set-out of the site using Total Station to accurately reflect the CAD design on the landscape
This might sound like a long-winded process to many, but to us it is about optimisation of all of the outcomes we are after. Namely:
- Client Satisfaction
- Landscape Harmony
- Water-use Efficiency
- System Performance
- Ease of Management & Harvest
The use of this whole process with Dalpura’s 1998 planting was made even more important by our ground preparation contractors clearing all the scant layer of topsoil in what was an executive decision that was quite disastrous when your soil is basically gravel! So we really started behind the 8 ball when we took the job back from these contractors. This only vindicates the whole process that we ultimately undertook.
Inter-row Acacia dealbata (silver wattle), and regrowth from thinning (foreground)
with Eucalyptus microcarpa (grey box) planted in 1998. Cam Wilson centre.
GH: All the various forestry systems across Dalpura Farm are planted in tree mounds aligned on ‘Keyline pattern contours’, which direct the natural water flow from the valleys or drainage lines out across the slope towards the crest, as per the pioneering work of P.A. Yeomans. The mounds act as mini-swales, intercepting and spreading the rainfall across the site, helping to distribute it more evenly to all the trees. The gutters on the sides of the tree mounds also act as temporary catchments following heavy rainfall events, increasing the efficacy of interception and storage of run-off, & retaining moisture in the landscape for longer.
CM: You had quite a variety of tree species planted. Can you tell us about some of them, and about any particular relationships going on there. And in what other ways does Dalpura differ from your average, conventional forestry project?
DD: There are about 120 species that have been planted at Dalpura overall. In the 1998-2002 plantings we installed around 20,000 trees and about 20 species (I have detailed records at home but am in Mexico at the moment so referring to memory!). Following 2002 we then started to run out of room and we wanted to plant more trees as per our original layout plan of 1996/7, so started to plant out the pastoral areas of the property. These plantings included more non-timber product species along with timber species; plantings that were a Permaculture/Keyline™ spin on J. Russell Smith’s 1927 classic, ‘Tree Crops: A Permanent Agriculture’. I call this kind of thing Keyline™ Mark IV as neither Yeomans Snr. nor Jnrs. ever applied Keyline™ in this way to my knowledge.
The project differs obviously from the industrial forest production where large areas of single species, often with cloned genetics are grown, where often biota are controlled chemically and the whole planting is clear felled at the end of each rotation. At other farm forestry sites it is common to follow a similar process only on a smaller more integrated scale. Here obviously we are integrating and including many species, including fauna and multiple methodologies of both landscape patterning but also management regimes. It’s a lot more complicated that’s for sure.
In the 1998-2002 plantings we were intent on developing a mixed species layout where the various species complexes (typically made of two species in each complex) were placed according to soil type and aspect. We basically decided this from the initial ‘high-level’ planning and then when the rows were prepared and the trees grown and delivered we then made the decisions to ultimately place the trees as a planting team. We had a great crew with us on that job, made up of new and old heads and it was an interesting process that did and didn’t work. What didn’t work was more a function of tree genetics than anything else, plus some pest animal issues as well.
New revegetation planting (2009)
Each complex throughout these systems are composed of a non-legume (all Eucalypts except for Grevillea robusta). In the 1998 systems we experimented with inter-row layouts where we would have the following layout as an example:
The specific intent of this layout (3m x 3m) was to have the fast growing Acacias (either Acacia dealbata or A. mearnsii) grow fast and fill the canopy quickly forcing the slower growing Eucalypts to ‘search’ for the available ‘light well’ and therefore reduce side-branching and improve on their form. This has and hasn’t worked. Though with some of the species we are working with they are very slow growing and their Acacia partners were perhaps too fast, though we are still waiting to see the full effect of this over time.
Otherwise in the 2002 planting we went a lot more ‘conventional’ with the following layout:
This appears to be a much better layout overall and so we are sticking with this one by and large. We have dabbled here and there with interplanted layouts in the main forestry complexes but have found they are more cumbersome when on a larger scale. That said on some sites we have worked with such as at Geelong Grammar School (1999-2000) and at the Shell Refinery at Corio (1999-2001) inter-planting worked quite well.
This kind of layout goes like this:
It all comes down to being what works for the forest ‘sociology’, which is reflected in tree performance and how easy it is to manage the systems especially when it comes time to thin the systems. Then things start to get much more complicated. These are times when you can appreciate why industrial foresters go for single height class, single species systems: but then a forest isn’t made of one species and one height class is it?
In 2000 we planted a paddock with a interesting array of ‘Tree Crops’, most of which were exotic species. This paddock we know as TC8 (all species complexes across the farm are individually codified) and it has three rows of Tree Crops at 5m row spacings every 24m. This system includes classic tree crops such as Gleditsia triacanthos var. inermis (thornless honey locust), Ceratonia siliqua (carob), Morus nigra (black mulberry), Quercus ilex (holm oak), Q. suber (cork oak), Q.robur var. fastigiata (fastigate english oak) plus Cytisus palmensis (tagasaste) and Atriplex nummularia (old man saltbush) as interplants between all of the tree crops. This system had ‘Leaky Hose’ subsurface irrigation installed in 2003 and is going along quite well, except the tagasaste’s have been hit pretty hard by the ‘roos.
From 2004 we were filling in the gaps ‘up the back’ of Dalpura and we decided to get a lot more complex with our plantings in the remaining places free to plant. So this involved very complicated layouts with lots of species: some of which were really pushing the edges of experimentation. Some suffered accordingly as they revealed themselves to not be suited to the site whilst others have thrived and have led to further planting of those species. We also experimented with using very tall plastic tree guards due to the kangaroo predation throughout the property on some of the plantings.
Walled garden and new orchard. Polewood in foreground from 2004/5 thinnings
of 1998 plantings of Acacia dealbata & Acacia mearnsii (late black wattle)
GH: The initial native forestry systems were planted between 1998-2002. They cover ~18 hectares, and include sixteen species of Australian trees (nine species of Eucalypts, four Acacia species, two Casuarinas and Grevillea robusta). Since then we have broadened our species selection, experimenting on a small scale with mixed plantings of Acacias and Northern hemisphere hardwoods (a range of oak, ash, beech, elm, cherry, walnut, liquidamber and many others).
A key long-term goal with the timber plantations is to enhance the soil fertility within these systems, both for its own sake and to enable the growing of a wider range of species 30-50 years down the track. In terms of building soil fertility the purpose was to harness the benefits of interplanting nitrogen-fixing, leguminous trees such as Acacias with Eucalypts and other broad-leafed species. The diverse range of species leads to a richer and more complex mix of minerals and microbial life in the litter layer that is continually forming on the forest floor.
Probably the main difference between our approach to silvicultural management and that of other farm forestry growers is our system of managing the inter-row areas. We allow revegetation to occur naturally between every second row (predominantly pioneer undergrowth species such as prickly ti-tree, hedge wattle, prickly moses and also a range of native heaths, various grasses and ground covers, mosses and lichens…), mulching the alternate rows to maintain access for silvicultural management work and timber extraction. This system mimics a forest ecology, with the various tiers of vegetation performing a range of functions in the system – improving the soil below the surface through root action, and increasing the amount of organic matter deposited as forest litter (leaves, sticks, seed, branches and bark; bird droppings and animal scats…); acting as protective habitat for a greater number of birds and insects; & also reducing evaporation and mitigating the effect of damaging winds on the timber trees etc.
As well as this, we manage the coppice re-growth of hardwood species as a follow-up to our thinning regime, in order to create multiple-aged trees within a uniform-age-class plantation. Ultimately, around five-to-ten specimens of each species will be retained per hectare as semi-permanent inhabitants of the system. They will be used as a source of good quality seed for growing seedlings from that species, and will carry out all the ecological functions that mature trees perform in what will effectively become an analog forest.
Indifferent form displayed on Eucalyptus tricarpa. Poor genetics we think.
CM: As you’re trying things in forestry that might not have been ventured before, you’ll obviously be on an experiential learning curve, discovering some species and design aspects that are working well, and some that aren’t. The time frames involved in growing trees are considerable, so learning what we can from your experience could save people many years of wasted effort and expense. Can you give us some insights from your learning curve with this project. What worked, what didn’t, and what would you do differently? I noticed for example, that some species tended to be a bit crooked, perhaps not so good for using as timber, and some were stunted in growth, etc.
Some of your lessons will be location-specific, affected by regional climate, and also other factors like kangaroos, etc., but some will be lessons that can be applied in other countries and climate zones. Perhaps we should separate these for the benefit of all.
DD: As I have already mentioned the brief was the outset was clear, and George has enunciated it clearly in this interview. Quite a few well known Permaculture practitioners (including: Cam Wilson, Paul ‘Ringo’ Kean, Derek Ashby, David Holmgren and David Griffiths) have worked or advised at Dalpura Farm over the years and found things of interest there. It is a difficult site with its soils and the average rainfall since we started has been much less than average so its not what you would call an ideal site from that perspective. A few have been quite disparaging about what we have been doing, often though they have focused on some of the various system’s misgivings such as those you mentioned.
That said we felled trees in 2003/4 that were planted in 1998 and then ultimately milled and dried these for furniture after that. We have radically increased the biodiversity values of the site due to our layout style and management regime. The bulk of the systems are in good shape and we will continue ad infinitum to obtain timber and forest products from this site. We and others will continue to learn from George’s munificence and the different influences that all of the project’s players have had over the years. The current manager Matty Fahey is doing a great job and I can’t wait to see what the place looks like after nearly a year away. There is so much to see there and it is one of the sites in my portfolio that I learn the most from, and I am not the only one.
- Start small but experiment on the edges and nooks widely
- Go and check out others sites in your region or regions with similar climates
- Do a Master Tree Growers Course (www.mtg.unimelb.edu.au)
- Subscribe to Australian Agroforestry (www.mtg.unimelb.edu.au)
- Join your local Farm Forestry network
- Use high quality tree genetics from mixed, tested provenances
- Work with high quality nurseries
- Ensure high quality ground preparation and prepare a year or two ahead of planting
- Get the fungi going – mycorrhizal when planting and saprophytic when thinning
- Practice silviculture regularly: as our great, late mate Joe Polaischer used to say, "its working man’s yoga!"
Quercus robur var. fastigiata (fastigate
silvopastoral system planted in 2000
GH: There is a fair amount of truth in Chou Enlai’s observation that "it’s still too early to tell". We are attempting to create inter-generational forestry systems along the model of Northern European practices starting from a fixed point in time. A number of the trees being planted are not intended to be harvested until well beyond my lifetime, and some past my childrens’ life times as well.
Part of the strategy of Darren’s design thinking was to plant a variety of species which have staggered time-lines from planting to harvest. The Acacia mearnsii and A. dealbata (Late black wattle and Silver wattle) are expected to be ready for harvest at around 15-20 years old, whereas with the River red gums and Red ironbark (Eucalyptus camuldulensis and E. tricarpa) we are looking at 35 years+. And with Californian redwoods (Sequoia sempervirens) and some other species we are probably looking at 80-100 years+.
Ironically, some of the trees exhibiting poorer form which you refer to are ones like Red ironbark and Yellow gum (E. tricarpa and E. leucoxylon), which are indigenous to this area, and adapted to growing in gravelly soils with moderate rainfall. We have found that trees do not respond entirely predictably to new and unfamiliar conditions. Experimentation with a wide range of species often brings surprising results.
Lessons applicable in region: Establishing the plantations on a Keyline layout has been invaluable, and is particularly applicable to lower rainfall regions. Our historical rainfall is around the 24" (600mm) mark, but having experienced a number of below average years since planting, capturing and utilising the available rainfall has been critical in the trees’ development, and, in some cases, survival.
One of the main unanticipated problems has been kangaroo predation on certain species, especially Blackwood and Lightwood (A. melanoxylon and A. implexa), as well as many of the exotic broad-leafed species. We have evolved a guarding system to deal with this predation, using 2m tall plastic guards attached to 7′ hardwood stakes. While the initial capital cost and follow-up labour is not cheap, we have been able to re-use the guards a number of times over.
Lessons applicable almost anywhere: Leaving every 2nd row to natural re-vegetation, and mulching to increase the breakdown of woody organic matter and provide more fungal food for soil biota.
Experiment with a broad range of species, and allow time to observe how they respond to a new environment. For example, Sugar gum and Spotted gum seedlings (E. cladocalyx and Corymbia maculata) were planted close to one another back in 1998. The Sugar gum boomed after the first couple of years, whereas the Spotted gum suffered from frost events in their early years, and were probably about 1.5m tall on average compared to the Sugar gums’ 8-10m after five years’ growth. However the Spotted gum has gradually taken off, and caught the Sugar gum in spite of the initial growth differential.
Close up of the magnificent Eucalyptus tricarpa
CM: This property is 140 acres, but do you think there’s anything the average guy on a quarter acre could be doing along these lines as well?
DD: Forestry can be done anywhere and Geoff’s ‘Food Forest’ video shows that the elements of forestry expand on the view we’ve been putting out there for a long time now: That the structure of forests never changes much wherever you are, rather it is the species that change, though their roles as life forms don’t within each forest. A forest is also made up of more than just the plants: it is a living, dynamic and ever evolving system that includes all of the kingdoms of nature.
As for your ¼ acre block, food forestry will be your best bet due to the practical issues of felling trees for timber production etc. By and large it will be non-timber forest production. That said you can do some very creative kerb-side coppicing for the rocket stove! Urban mixed species, multi-purpose agroforestry in the Zone 3 & 4 landscapes of our urban and peri-urban spaces makes a huge amount of sense as we move into the ‘new carbon’ economy (as opposed to ‘old’ or fossil carbon) where our wastes are cycled locally into a range of high quality products.
Echium candicans (pride of madiera) bee forage avenue planting (foreground) with
Cytisus palmensis (tagasaste) nurse planting in Keyline parkland
CM: And finally, a question specifically for the owner, George Howson: Investing time and money and ignoring potential lost income from the land in the interim takes some determined long term thinking. Can you give us a rough idea of investment cost, and expected returns?
GH: I think that any evaluation of the financial returns on specialty timber growing is ultimately academic, given the extended time-frames we are dealing with before many of the trees are ready for harvesting. Many of the intended returns from this project will not be measurable in economic terms. However, to answer your question as best I can, my underlying assumption has been that farm-grown timber will appreciate in value in excess of CPI over its financial life-cycle, and that the capital value of the property, and increased production potential due to increases in fertility levels, will generate growth in excess of the value of comparable rural land. Unfortunately, I won’t still be around by the time this project is really coming to fruition, and beginning to realise its true economic/aesthetic/ecological/social and farming potential.
One of the hidden benefits of working on a project of this nature has been the development in my own skills and knowledge as a designer. Working with Darren and other people such as Dave Griffiths of Geometree, and watching how systems evolve and develop over many years has been a great education. Very challenging at times, exciting and tremendously satisfying at others, but overall a richly rewarding journey.
Xanthorrhoea australis (austral grass tree) detail