This knowledge is then taken and integrated into a more intricate system of planting known as:
Layering or Stacking.
In permaculture and forest gardening, seven layers are identified. From the most significant to the least they are: 1 – canopy trees, 2 – secondary trees, 3 – shrubs, 4 – herbaceous layer, 5 – root crops, 6 – ground cover plants, and 7 – climbers.
A mature ecosystem such as ancient woodland has a huge number of relationships between its component parts: trees, understory, ground cover, soil, fungi, insects and other animals. Plants grow at different heights and come into leaf, flower and fruit at different times. This allows a diverse community of life to grow in a relatively small space. For example garlic comes into leaf on the woodland floor in the time before the top canopy re-appears with the spring, thus the garlic gets sunlight. The productivity of such a forest in terms of how much new growth it produces exceeds the most productive wheat field. It is in this observation of how more productive a wood may be on far less input of fertilisers that the potential productivity of a permaculture design is modelled. The many connections in a wood contribute together to a proliferation of opportunities for amplifier feedbacks to evolve that in turn maximise energy flow through the system.