Fully develop the nucleus before moving on, planning for highly intensive, biologically based food, fiber, and energy production at the doorstep.
- Plant stacking: use varying heights of plants to obtain yields from more than one layer
- Time Stacking: in combination with the above, utilize species that provide yields early, thus gaining quick rewards from the intensive energy input of developing a space for a long term yield such as avocado’s or macadamia’s.
To grow food as locally as possible requires doing so in an intensive way rather than the extensive, industrial system which currently reigns. This system is flawed because of the waste in transportation and distribution and its reliance on fossil fuel derived inputs such as synthetic fertilizers and chemical pesticides. With global resources dwindling, yet being propped up momentarily by controversial extractive practices like fracking, we must take steps towards a lower carbon society. A simple reflective glance to times of war indicate that when resources are needed to be conserved, government programs and media campaigns spur this effort. Victory Gardens were exactly this fact and produced a good quantity of food in those days of WWII. This reduced the fossil fuel input from tractors but also transportation. Thus we aim for a layered approach to meeting our needs and designing these systems to fulfill cycles and allowing energy to perpetuate itself.
Some might argue that the space is not there to produce food locally, but with rampant suburban development globally, its obvious that the resources used to keep succession at bay could be diverted into food production and the creation of resilient communities with edible landscapes. It’s a matter of good design not just environmentally, but also how people organize themselves as well as local green businesses to design, install, support, and maintain for some. Lawns require massive time, money, and energy commitments to maintain this monoculture and could be converted into food production, water harvesting features, and habitat for the wild creatures.
On a practical level, people tend to spread out too quickly on sites in the rush that our society dictates. However, our use of resources is much more wisely leveraged through “developing nuclei thoroughly and letting them merge over time”. In essence we build on the idea of guilds and the inherent resilience in diversity. Elements within a design can be thought of as part of an overall guild, not just beneficial plant associations (patterns to details). Each guild over time gets further planted out (or built) and begins to occupy dynamic layers within space. At varying times, yields are harnessed within weeks while others take 10’s of years depending on the element within the design. This time and plant stacking aspect of this principle is dependent on creative human interaction so don’t forget that layer within the design as it is not static. The forest garden, or food forest, is a direct application of this principle and the abundant and holistic yields that cascade from mimicking a great teacher: the forest.
While some ecosystems have more layers, this generally is a seven layered approach, which utilizes emerging energies to create stable systems. This is sun and photosynthetic energy driven (plant growth equals more solar panels so to speak) meeting the evolution of soils moving from bacterial to fungal. This union is a perfect example of accelerating succession through inherent systems at play in nature and our creative interaction with techniques like chop and drop. As more trees develop, the soil continually shifts fungally and sunlight hitting lower plants is lessened. This
means that in the early parts of the system between fruit trees, annuals can easily be grown. In 2013 I planted corn, beans and squash around my new apple and cherry trees to be a fully functional guild. The corn helped to shade the tree in the summer while the squash suppressed weeds and aided in moisture retention. These annuals also complimented the perennial support species like comfrey, mint, yarrow, and goats rue. While these perennials are small it is easy to drop in annual seeds as such and let them absorb and transform sunlight into carbon above and below the soil instead of it becoming entropy (sunlight hitting mulch and causing oxidative breakdown of carbon matter). This helps to turn what appears to be orderly early stages into chaotic positive interactions.
This can also be done on a small-scale with broccoli and lettuce. While broccoli take 90 days and 18 in (45 cm) of spacing, you can plant lettuce (45 days) in between broccoli to take advantage of the space and reduce weed competition. In this sense, just when the broccoli is putting on rapid growth and occupying more space, the lettuce is ready and is cut as a yield and opens the space up for the brocolli to continue to flourish. Radishes can be grown with lettuce in the same effect and over time different combinations are creatively engaged. This way the small-scale intensive system is truly achieved and our need to dig two beds, one for lettuce and one for broccoli, is alleviated.
Back to the system of food forests, our perennial systems are developed knowing that we should plant different species for different yielding times. Below is a couple of slides from a food forest (then an animation) that I planted in New Zealand in 2006. It details the layers with avocado’s being the main aim for the client. However, these trees take four to six years to really produce leaving plenty of space and time for varying yields to be realized.
Some of the those yields come within weeks as comfrey can be a great example of energy cycling with a simple chop and drop mulch system. It was planted on the down hillside of the small tree earthwork that took place for each one of the anchor trees (avocado). The comfrey absorbs the water and nutrients that are moving downhill from rainfall and irrigation. The tree was given compost and small amounts of liquid worm tea which translated into lush comfrey leaves. These were easily mulched and fed the tree as they were planted in relative location. The sunchoke, or Jerusalem Artichoke (Helianthus tuberosus), also provided a quick yield as they are ready to harvest their nutritious tuber after one growing season. They are also part of the guild or nuclei and they perform multiple functions. Their stalks at the end of the growing year, as well as the comfrey through the growing season, were cut finely giving edge to the organic matter so it breaks down faster. In addition to these chop and drop materials, tagasaste, a multifunctional nitrogen-fixing tree, was given to the avocado so that the important function of mulch or soil fertility was met by multiple elements. By cutting the tagasaste, this was a direct application of the use of biological resources as its rich in nitrogen leaves alleviated us from buying chemically derived fertilizers to fertilize the system. Its carbon rich branches, as the tagasaste coppices well, help to accelerate succession in the soil as it pushes it towards fungal domination. These branches were located in the same zone as the trees, zone 2, and were carried downhill showing how energy efficient planning allows this to happen with ease. This explanation highlights virtually all of the Mollisonian principles and shows how the food forest is exemplary of the patterns of space and time in nature.
Furthermore, in this particular food forest the currants (Ribes sp.) also give yields quickly. By year two they are growing into quite mature plants and producing their very nutritious fruits. Layering them could help to create a larger plant and cover more space in the food forest. The elderberry (Sambucus sp.) is not far behind and by year three, a bit of coppicing on that plant maybe in order to make sure space for other plants is not hindered. It will yield its flowers and fruits which are processed into value added products. The guild plants, comfrey and Jerusalem Artichoke, will increase in their size as they are rhizominous plants and will take off after a full year in the ground. Other species can be added such as herbs either Mediterranean or something like lemongrass or other chop and drop species like cana lily.
As the forest garden matures it is important to notice how the canopy of the system closes and your role in maintaining edge. Once the canopy closes the system reaches maturity. What can be done, and what is illustrated in a representation of this above Avocado food forest in the below animation slideshow, is to remove some of the canopy over time to keep the system yielding at multiple layers and ensuring that the space was used fully in the beginning years of the system.
Because the text at the bottom of the sequence is hard to read here it is once again in the following bullets:
- year 1, initial plantings of Avocado and its guilds, plan view
- year 1, initial plantings of Avocado and its guilds, section view with details on the individual tree earthworks
- year 1, initial plantings of Avocado and its guilds and currant and elderberry layer added, plan view
- year 2, all elements growing, yields from currants and maybe elderberries. Comfrey and Jerusalem Artichoke can be propagated at the beginning of the year to expand guilds.
- year 3, currants reach maturing size and are yielding heavily, elderberry is coppiced every year there after to keep size and ease of harvest as it is yielding, avocado grows more rapidly from here on out.
- year 4, Avocado’s growing and with their graft they have the chance of flowering for the first time. currants and elderberry maintaining size but yielding
- Year 5, Avocado’s flowering for sure and growing much more rapidly, shade building in the understory, herb layer between changing, soil building underneath trees. Lower layers still yielding.
- year 6, At the end of the year first Avocado’s ripening. Canopy space getting close to touching. Lower layers still yielding.
- Year 7, Avocado’s growing really rapidly, producing fruits. Lower layers not yielding as much as shade is quite heavy.
- end of year 7, easy to see what would happen to species underneath if they had more space and how the canopies of Avocado’s benefit from removal of some of the trees so that correct spacing occurs.
- Year 8, canopy opened and space to grow rapidly occurs. Trees are heavily bearing now and lower layers are yielding once more as well. Most of the biomass of the cut trees was used for mulch so trees are fed well and producing abundantly.
To understand why we would over plant it is important to note that Avocado’s are normally spaced at 10 m when planting. They are massive trees when they reach maturity. So it is better to plant them tighter (seven meter) and get fruit production for a few years since Avocado’s biologically grown are quite expensive. You can quickly get your Return on Investment even at around $25 Kiwi dollars for a grafted fruit tree in the context of where this particular food forest was planted. 10 fruit and you have got your ROI. Additionally you get huge volumes of biomass from the selected out Avocado’s thus building natural capitol. You would harvest the ones that appear weaker in the system while trying to go for some uniform spacing.
So again yields come from different layers and at different times in the system. Animals can also be added in and that adds in another layer of fertility, pest control, but also management. It can reduce your need to manage the herb layer but when not moved correctly they can also be damaging and polluting. As the system matures pigs can take advantage of fallen fruits and can again fill the same functions as the chicken. So plant densely, obtain yields at different times and from different layers. Creativity goes a long way and never forget the human element in this principle. The above graphics represent a simple version, stacking with more nitrogen fixers and support species is in order. The forest has a lot to teach, so don’t forget your retreats to zone 5 to learn.
Mollison, B. & Slay, R.M. (1991) Introdcution to permaculture. 2nd Edition. Sisters Creek, Tasmania, Australia. Tagari.