The essence of permaculture is creating symbiotic relationships between plants and animals that conserve valuable resources. One example of a symbiotic working relationship is keeping chickens in orchards. The chickens control weeds and pests and contribute high phosphorus fertilizer. The trees provide shade and fallen fruit to the chickens. Human labor is saved and outside inputs of chicken feed and fertilizer are not necessary.
Humans also benefit from the fruit of the orchard and the eggs and meat of the chickens.
This means that the site is producing more energy than it is consuming, an indication of sustainability. One way this is accomplished through design is land use that leaves a certain amount of wilderness area. Efficient use of the land allows wild plants and animals the space necessary to continue their evolution. Although leaving space for wildlife may mean smaller production zones, yields can be increased many ways, especially when the designer uses vertical space for multi-storied planting such as kiwi, grape, or pea trellises. Permaculturalists strengthen their bioregion through education, and mutual exchange of ideas, skills and information, thus furthering the ethics and goals of sustainability.