Ecological Design is the conscious and intuitive effort to impose meaningful order, and where permaculturists put their ethics and principles into practice. Permaculture design is based on observing and mimicking natural systems. A number of design principles have been developed to guide permaculturists (for example David Holmgren’s formulation below), but systems thinking is an essential companion to these principles. David Holmgren says that “from a systems ecology perspective, ‘design by nature’ is not simply a metaphor but a result of the forces of self-organisation which can be observed everywhere in the living and wider universe”. In other words, permaculture is more systemic than systematic. Permaculture is not the principles. It is not a formula to memorize, or a recipe to follow. To practice permaculture well is not necessarily to store a vast quantity of facts. It is better to understand underlying patterns.
In essence permaculture can be described as a system of design that seeks to recognize and maximize beneficial relationships while minimizing or eliminating harmful relationships. Permaculture is not a set of principles but rather a way of seeing that gives equal value to the links between elements of a system as to the elements themselves. Like other ecological design strategies, permaculture relies on an understanding of ecological principles such as diversity and interdependence, and strives to maximize networks of beneficial relationships in order to reduce risks within systems. Such an approach to design can be applied to biological and non-biological systems.
The commonly recognized permaculture interpretation of an orchard is a food forest, where a chemically managed monoculture is replaced by an organic polyculture complete with diverse ground cover and, potentially, domesticated animal inhabitants. In this context, a permaculturist uses design strategies gleaned from nature as well as specific science knowledge. This science knowledge could include an understanding of: leguminous plants and their role in fixing nitrogen; soil porosity and permeability; soil chemistry; and, predator – prey relationships among resident insects. Permaculturists also engage in the practice of science, for example by experimenting with new plant guilds – complementary plantings (usually of three) of mutually beneficial species – such as the ‘Three Sisters’ (originated by the Hopi tribe of North America): corn, beans, and squash.
A permaculture interpretation of a home is a structure that is not consumptive and polluting, but one that functions more like a tree: consisting of natural materials and gaining its energy directly from the sun. In this context, the design inspiration may be biological but the science knowledge is astronomical and physical. For example, in order to design and build a home that heats itself in winter but does not overheat in summer it is critical to understand the different sun angles and directions at various times of year. Additionally, a passive solar home requires a balance of incoming solar energy, thermal mass, and insulation. Attaining this balance requires knowledge of physics and particularly thermodynamics.
Having said that permaculture is not a set of principles to memorise, the formulation of principles can be helpful as a guide to some of the things worth thinking about when designing a system. The 12 principles linked below are the work of David Holmgren, co-founder of the Permaculture concept, as reformulated in his book "Permaculture; Principles and Pathways beyond Sustainability" (2003) but as stated above other conceptualisations have been developed, as well as assorted permaculture 'truisms'. All these have validity, and all are no more than reminders to help us develop designs that are responsive to the specific situation and which embody the characteristsics of ecological systems.