Permaculture Designers Manual
CHAPTER 4 – PATTERN UNDERSTANDING
Section 4.9 –
Spirals in Permaculture
Implicit in many of the phenomena discussed are the forms of spirals. These may be revolving (dynamic) or fixed (static), and arise as a consequence of deformations inflow, or are rather an intrinsic property of a specific velocity of flow over surfaces. Other spiral paths are traced out by orbiting bodies over time or are shapes developed by organisms developing a compact form (e.g. mollusks) that is analogous to annidation. Spiral forms are made visible by plants as whorls of leaves and branches.
D’arcy Thompson (1952) in his book On Growth and Form, discusses some of the quantitative or geometric qualities of spiral phenomena, which are hidden or revealed in many natural forms.
A long spiral in a section is the “S” form of humid landscape slopes (and the yin-yang symbol). Three-dimensional spirals form long ribbons of complex shape. Even within the molecular forms of matter, DNA reveals a double helix form. Spirals are, in effect, single streamlines of vortices, tori, or sap flows. Spirals arise from the interaction of streaming and its subsequent deflection of flow around vortices. Storl 1978, Culture and Horticulture, Biodynamic Literature Rhode Island) points out the spiral arrangement of leaves in many plants, where leaves are from one-half way, one-third way and so on around the stem from the preceding leaf, or to the next leaf. Such placements may progress in a regular (Fibonacci) series, each following on from the sum of the two preceding ratios:
1:2 + 1:3 = 2:5; 1:3 + 2:5 = 3:8, etc., so we get 5:13, 8:21, 13:34 and onwards. These sequences are found in plants and in planetary orbits, so that “Venus forms five loops (retrogressions) below the ecliptic in eight years” Storl sees a relation between the forms of plants and of planets in these progressions, as we can see in the orders of size. Like so many real-life phenomena, natural spirals are not “perfect“, but “show slight progression” and gradually lose phase over long periods (Storl, ibid). We can often use the spiral form in design, both to create compact forms of otherwise spread-out placements and to guide water and wind flows to serve our purposes in a landscape. We can see the application of spiral forms to technology in everyday life as screws, propellers, impellers, turbines, and some gears. Some species of sharks and invertebrates develop spiral gut lining to increase absorption, or spiral cilia to convey mucus and food or particles in or out of the organism. Plants such as Convolvulus use spiral anchors in the earth, as do some parasites in animal flesh. Thus, spirals are found where harmonic flow, compact form, efficient array, increased exchange, transport, or anchoring is needed. We can make use of such forms at the appropriate places in our designs.