Functional, productive diversity is an essential element in the design science of permaculture. Diversity is a very good thing and we absolutely want to be stacking as much useful diversity into our designs as we can.
There are a few things to note, however, about the use of diversity in design.
Firstly, as mentioned above, we want our diversity to be functional and productive. This means that we want a diversity that has a use. We do not just stick in as many different plants as we can just for the sake of it, much like a hoarder filling their house with junk collected off the street. While collecting plants can be a highly beneficial pastime, especially when we are focused on the saving of unique genetic stock, we want these plants (and animals) to be ones that are useful to us within our year-to-year lifestyle.
Ideally the living elements we stack into our systems are first and foremost ones we like to eat or use for other purposes such as firewood, timber, cloth, medicine, animal forage/fodder, and so on. Secondly are the living elements we use functionally such as those for windbreaks, groundcover, shade, firebreaks, soil remediation, etc.
Ideally, however, most of the elements we select perform multiple functions, i.e. a tree may function as both a windbreak and animal forage.
So diversity is good, we want it, we need it and a system with a high diversity, particularly relating to designed edge, will be a resilient system. Having a high diversity ensures that there will always be something available for use as food. If we have a diverse orchard or food forest filled with different species of trees that ripen fruit at different times of the year, then we will be assured of high quality, nutritious fruit year round.
Diversity can also function in the process of pest control. The opposite is a monoculture where one living element is packed into a single area with no relief for any other living element. For a pest this is like arriving at a free buffet. There is no need to go anywhere else, here is an opportunity to eat ones fill… potentially for generations! It’s easy to see then how a cycle of chemical-based pest control rapidly becomes the predominant strategy in monoculture systems.
Monoculture does not exist anywhere in nature, and pest control is a natural function of a natural system in the balance of food-pest-predator.
It is this natural ecological function that we seek to harmonise with in our permaculture designs, and the more that we can harmonise the easier and more robust our planned systems will be.
What interests me in all of this, however, is how diversity plays out across larger scales. For example if we wish to put permaculture design into place in a commercial system where we intend on creating product for sale, how do we go about it and still honour the ideal of permaculture? The other option for larger scale sites is in community structure. There is a third option, and this is the landowner who just happens to buy a big plot for themselves or their family. To this third group I offer my best wishes and good luck. Once we get above about 5, and at the upper end 10 or so acres with pasture included, we are moving into territory where the site will never achieve any kind of consistent level of management. Unless huge areas are put into pasture (which then begins to model a sort of commercial system, as the cattle will undoubtedly need to be sold and also such a system begins to compromise on the ideals of permaculture) or large areas are left to native regrowth forest… then bigger is most certainly not better.
In a commercial system, firstly, we have to understand that the moment we are removing grown materials off-site we have already created our very first sacrifice to the ideal of permaculture. This is ok, permaculture is an ideal after all, and ideals are guiding potentials for us to aspire to rather than rigid dogma’s that shame us when we fail. Let us not make permaculture another dogma and recognise that, especially at this point in history, all our systems are in transition. We can use the ideal to guide our transition to more efficient, ecologically harmonious and healthy systems while recognising that there is need to make income, and that a permaculture system even when it is commercial is still so much better than a chemical-driven monoculture.
So when we grow for commercial scale we are making a compromise. We will have to find out somehow how to bring the extra materials back in to the site. This can often be somewhat easily done for example when stacking animals more densely it is likely we will need a supplemental feed. I do not know of any commercial chicken growers who do not supplement their feed (including those on pasture or free-range), and if there are any out there please reach out as I would love to know how you do it!
Other ways of bringing resources back in include collecting food scraps from local markets or restaurants or fruit/vegetable shops and composting it for use in our own gardens.
Once we have satisfied this compromise and ensured that we are still in a soil-regenerative process, then we come to the interesting planning of our commercial product and how to contemplate where our diversity fits in to such a system. This same planning process is going to need to be considered within a community as some crops are much better grown in a bulk manner for the commons.
The relationship between diversity and scale is something I have contemplated over a lot. I have created backyard gardens for parents and friends, and I have worked on large-scale sites. Doing so has had my contemplate how do we design for bigger scale systems?
It became obvious to me that designing a larger scale system was not simply taking a small system, like a home food forest garden, and stretching it out wider to encompass a much bigger area. I’ve seen versions of this and it makes both maintenance and harvesting a challenging ordeal. When a large site has every area laid out as diverse assemblies then in order to harvest it requires a lot of moving around. If I have, for example, mango trees planted randomly throughout a large site within complex assemblies of other plants then when mango season comes on I will have to walk that entire site regularly for a harvest. I guarantee a lot of the harvest will be missed.
Ecologically this is a beneficial system, in efficiency however there is much better ways we can think about designing.
This is where zoning becomes highly important. On a large site, however, the designated zone areas can still be somewhat large and only give one piece of the puzzle.
The other piece of the puzzle, in my mind, is in the intentionally planned life assemblies.
In a small system we can stack diversity in hard and heavy. An acre or two can contain a huge range of plants and some domestic animals, and as it is so small that if we spend a couple of hours every day we can achieve a level of intimacy with the whole site. This is impossible to maintain on a larger, site, however. We need to be much more conscious about our growing areas.
In large scale permaculture diversity is stretched out over the entire site.
What I mean by this is that over the entire site we will have the same kind of diversity that a small-scale site has. This may be 100+ productive plants and animals. However as we are on a bigger site we can’t, and don’t need, to have all of this living elements scattered throughout the whole site. Instead we design assemblies of three to five, and maybe quite a few more in some situations like a kitchen garden, living elements and grow them in bulk in specific areas.
An example comes from the site I am currently working on in Thailand. The existing infrastructure that I have come in to design for had, much to my delight, a pre-installed chinampa system. However this 3/4 acre system, sadly, was growing nothing but lemongrass. What an opportunity!
So I have been in the process of redesigning it to grow a coconut overstory with the lemongrass underneath, interspersed with leguminous support species. On trellis over the water canals will be grown various cucurbits, in the water canals fish are stocked and kangkong will be grown on the surface of the water. Lastly a rotational duck grazing system will be introduced to clean up harvested kangkong and cucurbit, provide fertility for coconuts and nitrogen for algae production and give a yield of eggs. So in this one system we have five main productive elements stretched over quite a large area. The short term yield will be enough to provide additional food to the school kitchen whilst the mid and long-term yields of lemongrass and coconut will be used to press for oil in the production of spa products to generate an income for this not-for-profit school.
In this same area, however, if it was to be our only growing area, it would be easy to create a massive amount of diversity. The increase in diversity would come with an increase in time needed to manage and a decrease of bulk harvest possible, which we would be fine if this was where we spent most of our day.
Now on a large site, like this one is, the same kind of assembly system can be repeated throughout the site. There is a section where milking goats are being grazed under oil palm for a total of two products. We can easily add in, say, a layer of moringa plants under the palm for a third potential product along with an assembly of support species that doubly function as animal fodder for the goats.
There are areas that can be made into paddy production which can then be used to grow aquatic crops like taro. We can stack into the paddy, also, ducks, azolla as support and feed, and fish for a total of three products.
Other sections, like a bare slope, can be used to grow a medium term crop of banana and pineapple which can eventually give way to mixed food forest with a major in jackfruit or mango and an understory of rose apple.
Small herb gardens can be built around the school where kitchen herbs like Thai basil, lemongrass, kaffir lime leaf, galangal, chilli and more can be grown with a partial shade element of papaya.
As you can see, as we include these intentional assemblies, zoned appropriately, throughout the site the diversity of the site rapidly increases yet with a greater volume for either commercial production or feeding a large community.
In summary, as scale goes up diversity is stretched out into intentional assemblies placed appropriately throughout the site for maximal efficiency, greater yields and potential harvest.