DEHESA AUSTRALIS

“A society grows great when old people plant trees whose shade they know they shall never sit in.” – Greek proverb.

 

This paper is an invitation to join a discussion on the future of Tree Crops in Regenerative Agriculture in the Mediterranean Climate Regions of the Australian continent. In particular the research, design and application of the agroforestry/silvopasture systems of the Iberian Peninsula known as Dehesa and their potential as models for analogous systems in climatically relevant areas of Australia; hence the term Dehesa Australis(first coined by Paul “Speedy” Ward).

NB: we wish to strongly note that we are not encouraging a wholesale, cut-and-paste re-creation of any given system for the sake of it; rather, Dehesa Australis is an example of applying the Sibling Regions framework to explore climatic analogues and identify patterns of land use that can can be tweaked for local contexts and applied only after a thorough consideration of particulars.     

A stunning visual model of the broad-scale Dehesa system in Spain’s Extramadura region.

“País de Quercus: Una selva domesticada”: Luis Manuel Silgo. 2011

 

                                                 What is Dehesa?

For those not so familiar with the Spanish term, Dehesa(or ‘Montados’ in Portuguese) describes a semi-domesticated, savannah landscape established centuries ago as an agro-silvo-pastoral system within the Iberian Peninsula. Featuring widely spaced oak trees(commonly Quercus ilex var. Ballotas, Quercus rotundifolia and Quercus suber, but species can vary with locale) growing in grass lands used as both pasture for live stock and to a lesser degree for the production of annual crops. The trees are spaced approximately every 40-60m to minimise water competition, maximise light for the pasture in the understory and acorn production for pigs and game. Specialised black Iberian pig breeds have their diets largely supplemented by the fallen acorns of the Oak over story. Commonly the Holm Oak(Q. ilex), a hardy evergreen, cork-like oak native to the region. The animals fatten up rapidly through the season of La Montanera(October to February) as the ripe acorns fall to the ground, each animal gaining approximately 60 kg in weight by eating up to 7 kilos of acorns per day. Their processed meat, known as Jamon de Iberia puro de Bellota, is famous for holding flavours and textures not only the result of the acorns but of the native shrubs and herbs found growing there like, wild oregano and thyme. On top of fresh air and excellent food, the true free range nature of the system provides the animals with adequate exercise needed for the fat to evenly infiltrate into the meat, another ingredient in it’s superlative quality. It is in fact the highest priced ham product in Europe. These systems cover more than 3 million hectares in the Iberian Peninsula and Greece and have great importance on the regions food production, economy and culture in general. Extra system yields include wild game, mushrooms, honey, cork, timber and firewood to say nothing of the extra environmental benefits of carbon sequestration, wildlife habitat and so on.

 

An established Dehesa system in the Extramadura region of Spain.
Image source: stock.adobe.com

                                             Why Dehesa Australis?

As outlined in the Regen Australis project, the future brings specific and acute challenges to the human communities of the Australian continent, particularly those living in the temperate to brittle regions. Projected drying trends, a lack of robust traditional cultural and agricultural systems to fall back on(what was here has been largely lost), very few recognised edible native plant crops, a ‘too-much-yet-to-lose-before-we-bother-changing’ head space of the people, a common misunderstanding of Australia’s unique hydrological cycles, often poor soils, salinity, ravenous parrots, etc…

A large motivator for this study was these regions lack of biomic analog to mimic for food production. A biome refers to certain dynamics in ecological communities. The same biome-types can be found in different parts of the world, containing different species but maintaining ecological similarities; for instance deserts, wetlands, tropical rainforest and as we will see, savanna are all types of biomes.

In many other temperate/mediterranean climate regions of the world which Europeans have colonised the local systems have to a large degree resembled their homes. i.e. even California had Oak Savanna with Prunus and Rubus spp understory etc. Here in the southern Australian latitudes we do have native savanna type systems however they are dominated by Myrtaceae, Fabaceae and Proteacea species. Nothing against dry, schlerophyl, eucalypt woodland but it doesn’t lend itself terribly well toward a hungry contemporary Australian*.

 

Bill Gammage’s revisionary “The Biggest Estate On Earth” demonstrates how much of the Australian continent was represented by the savanna biome as a result of Indigenous land management prior to European colonisation in 1788.

 

Of course the areas defined here are vast and broad and practices that may be appropriate for one site to another will vary, however there seems to be a strong leaning toward taking existing pasture and even unused land to establish the likes of Oak/Chestnut/Carob dominated savanna silvopasture type systems reminiscent of the Iberian Dehesa but here with the inclusion of many other relevant species that pre-industrial Iberians may not have had access to. These silvopasture systems coupled with Keyline and other water harvesting techniques custom to our high evaporation rates, using holistic rotational grazing with live stock to sequester soil carbon, programs for selectively breeding highly adapted perennial staple crops and further studies into dry land forestry(mallee eucalypts etc…) could see us developing and refining ever more robust and productive models.

These systems include extra yields of…

• various premium animal products
• tree fruit/nut crops
• honey
• timber
• fire wood
• craft wood
• cork
• charcoal
• wild herbs
• wild game
• eco-tourism etc…

Plus extra-environmental benefits of…

• wind reduction
• moderated temperature extremes
• moisture retention
• generally lower stock exposure to harsh elements
• minimised/distributed stock ‘camping’
• greater diversity in stock diet
• minimised soil erosion
• wildlife habitat
• great aesthetic appeal(increased land value)
• plus countless emergent ecological benefits…

 

An exploration of the eco-tourism appeal of Dehesa systems with the Rewilding Europe initiative.
“Rewilding Europe: the case of Western – Iberia”
~ WURKS NatureToGO: the case of Western – Iberia. 2014

 

                                           

‘Birding Extramadura’: Another of the wonderful eco-agricultural tourism innitiatives in Spain Extramadura region..

www.birdinginextremadura.com

 

We foresee variations on two main models. Firstly the classic savannah template of pasture dotted with widely spaced productive trees and secondly a model borrowing from the Agroforestry practice of ‘alley-cropping’ whereby trees are grown in rows(preferably on Keyline patterning) with the alleys between used for planned grazing or in some cases used to grow annual crops. It has been suggested that the former model is best suited to systems where the primary yield is the animal product while the latter would be more economically conducive to systems where both animal yields and tree crop yield are desired. The potential inclusion of multi-functioning understory plants would be decided on case by case.

                                                         Identify Your Biome

”No matter where one goes on planet Earth, there are families of plants and their associated animals that grow and thrive together in virtuous relationships with zero external inputs.” – Mark Shepard.

In his book ‘Restoration Agriculture’, author and farmer Mark Shepard suggests the first step in designing such systems is to identify the local endemic biome and then best mimic that biome using highly productive, hardy analogs as closely related to the original species as possible. As mentioned above our local biome is largely Myrtaceae (Eucalyptus, Melaleuca etc.) dominated dry to moist sclerophyll woodlands and savannahs with Fabaceae(Acacia) understory. There are many edible Myrtaceae from tropical and subtropical South America(Guava, Feijoa, Jaboticaba, Patanga, Grumichama etc…) and while many do well here they are predominantly understory plants and require summer watering and relatively rich soils. Australian Fabaceae has an excellent analog in the form of the Carob, a high value, multi purpose staple crop already perfectly adapted to our climate. The greater system however will need to be a composite of other traditional Mediterranean climate region’s(MCRs) agro/silvo/pastoral systems also taking advantage of MCRs ability to happily house many species from subtropical, semi-arid and temperate systems of the world. It is proposed that the Iberian Dehesa system be used as a basis for our model. However instead of using just the Iberian Oaks(Q. Ilex var. Ballots, Q. suber, Q. faginea etc) as the over story, we incorporate a number of over story species with emphasis on the following points…

• Hardiness to local conditions, especially precipitation/evaporation.
• Staple food production. Where applicable, tree species producing staple food types should be favoured. Staple foods for mammals are fats/oils, proteins and carbohydrates.
• Multiple function. Species offering greater range of functionality are to be preferred. Fodder, timber, medicinal, culinary, environmental etc.
• Superior varieties. It would be beneficial to intend to locate known superior varieties with proven performance. In the particular case of Oaks, varieties producing low-tannin acorns are to be favoured I.e Quercus ilex var. ballotas. NB: When intended for stock animal consumption low tannin acorns result in a superior meat product. However when discussing acorns as bulk, staple human food tannins can act as preservatives allowing for longer storage.

Such a list of potential species for Dehesa Australis systems may include…

Canopy
1. Oak, Quercus ssp.
Q. ilex, the Holm OakQ. rotundifolia, ‘Ballotas’
Q. suber, the Cork Oak
Q. lobata, Californian White Oak
Q. robur, the English Oak
Q. muhlenbergii, Chinquapin Oak
Q. prinus, Chestnut Oak
Q. alba, White Oak
Q. bicolor, Swamp White Oak
Q. faginea, Portuguese Oak
Q. pyrenaica, Pyranese Oak
plus many, many more…

2. Ceratonia seliqua, Carob(species of great importance, issue of tannins also applicable)
3. Morus spp., Mulberry
4. Diospyros spp., Persimmon
5. Prosopis spp., Mesquite
6. Castanea sativa, Chestnut
7. Gleditzia triacanthos, Honey Locust
8. Persica americana, Avocado
9. Casimoroa edulis, White Sapote
10. Arbutus unedo, Strawberry Tree
11. Macadamia spp., Macadamia
12. Prunus amygdalus, Almond
13. Pistachio spp.,
14. Pinus spp., Pine Nuts
15. Prunus salicifolia, Capulin Cherry
16. Araucaria bidwillii, Bunya Pine
17. Ficus spp., Figs
18. Olea europa, The Olive
19. Prunus armeniaca, Apricot
20. Eriobotyra japonica, Loquat
21. Inga edulis, Icecream Bean

 

                                                                Where To?

These ideas are nothing new. J. Russell Smith wrote of and suggested the implementation of such systems almost one hundred years ago in his seminal work ‘Tree Crops: A Permanent Agriculture’, in which he highlighted the ecologically stabilising effects that permanent, perennial, tree based agricultural systems had on not just the ecology but also on the local Human settlements. Many pre-industrial agricultural systems relied heavily upon the use of trees wether for pannage, fodder, fruit/nut crops, fuel, coppice products etc. and within the context of the more than likely low-energy future scenario we are moving into it is all but given that trees will once again be valued as the backbone of ecologically regenerative agricultural systems. Hopefully we can beat the onset of severe energy decline by establishing such systems before they spike.

 

We propose the Dehesa Australis project include…
1. Bringing together relevant parties, ready, willing and able to begin a more formal conversation on the subject.
2. List and describe all species/varieties that we find to be likely candidates for Australian Dehesa analogue plantings.
3. Locate all those relevant species/varieties that are currently present in Australia.
4. Locate and document all relevant/applicable systems currently existing in Australia.
5. Locate and document all relevant/applicable systems currently existing outside of Australia(The Dehesa of Iberia being but one).
6. List/locate all relevant species/varieties that currently are not believed to be in Australia and establish systems and relationships with relevant parties(breeders, botanical gardens, Australian quarantine etc) to enable a safe and streamlined means of importing desired propagation material from international sources.
7. Establish physical locations where we can collect and maintain entire arboretums of applicable species/varieties into Dehesa Australis collections. A place where the best varieties of the best species could be grown and kept for future application. Ideally at least one arboretum per major bio-region.
8. Long-sighted breeding programs which aim to cultivate hardy, precocious, high yielding varieties specific to each bio-region.

Australian Natural Resource Management groups like Landcare and other local catchment groups have, without question been one of the shining, pro-active lights in the greater national response to ecological degeneration. Historically, they have held strong ‘environmental conservationist’ positions, advocating for and implementing environmental rehabilitation of areas using exclusively endemic species. We suggest that these bodies consider expanding their modus operandi further beyond the strict and exclusive use of purely endemic species and to consider the inclusion of varieties that serve multiple eco/agri/cultural functions regardless of their region of origin(pending the appropriate environmental screening procedures).

 

                                                               The Future

There are many socio-economic reasons why these types of systems have not been appreciated let alone implemented in Australia. One of which is the relatively long time a tree takes to mature to a point where it is yielding and the resources it takes to nurse young trees and ensure they establish. However, in a world where the future dynamic of energy production and consumption appears so precarious it is a responsibility for us to invest at least some percentage of the relatively cheap and accessible resources currently at our disposal into these kinds of stable, robust agri/cultural systems. For far too long we have been driven by the single-bottom-line motive of profit over the extra-cultural and ecological benefits of these proposed tree based systems. I urge you to consider the many benefits these systems will have upon the generations to come and just how grateful they will be that we considered them a worthy investment of our time and resources.

Again…

“A society grows great when old men plant trees whose shade they know they shall never sit in.” – Greek proverb

 

*(N.B this is not about pro-colonialism or Eurocentric-ism but about productive, Regenerative Agricultural systems whatever model they resemble… We recognise that the indigenous and traditional peoples of Australia embody a deep, balanced and functioning working relationship with the land however precious little remains of their once continent wide, encyclopedic knowledge systems and it is unrealistic to think that contemporary Australia will soon adopt what is left of those methods. We recognise the monumental loss experienced by Indigenous Australians, honour the invaluable knowledge of country that remains and strongly support the exploration, documentation and dissemination of that knowledge where it is sanctioned and appropriate. The Indigenous forms of land stewardship represent an incredibly important wellspring from which to draw from in our quest to re-connect with country, along with the studies of regenerative eco-agri/cultural forms form Climatic Analogues and general Regenerative Agricultural studies).

References

 

See below the work of Dr Imma Farre in suggesting the Dehesa model in south Western Australia…

• http://www.abc.net.au/news/2012-04-02/wa-farmers-check-out-dehesa-system/3928092
• http://archive.agric.wa.gov.au/PC_95069.html
• http://www.sciencewa.net.au/topics/agriculture/item/1651-traditional-spanish-farming-system-may-bring-jam%C3%B3n-to-wheatbelt
• http://www.pigprogress.net/Breeding/Sow
• Feeding/2012/8/RESEARCH-Australia-examines-Iberian-traditional-pig-farming-PP009259W/

This paper is merely an integrated presentation of other peoples works. People such as…

David Holmgren
Darren Doherty
Bill Mollison
J. Russell Smith
Mark Shepard
Dave Jacke
Eric Toensmeier

… and the many others who share the vision of a stable, ‘permanent’ agriculture based on tree crops.

© Byron Joel, Oak Tree Designs, 2014

On July 28, 2018   /   Media