Skip to content
Permagora
Back to the glossary

In the pathway: Designing your site

Sectors

The external influences that cross the site: sun, winds, water, noise, views, frost.

Watch the videoL'analyse des secteursRECOfilms

Explanation

Unlike zones (based on visit frequency), sectors map the incoming energies. Identifying these flows lets you intelligently position windbreak hedges, ponds, greenhouses, and areas of shade or protection. A tool complementary to zones in permaculture design, theorised by Bill Mollison.

Refined definition

Sectors are the flows of energy or influence that enter the site from outside: the path of the sun through the seasons, prevailing winds, water runoff, views (beautiful or unpleasant), noise, a pollution source, potential fire, frost descending from the heights. Each sector can be amplified (capturing the winter sun, welcoming the rain) or blocked (a hedge against the north wind, a screen of vegetation in front of an ugly view).

Key points

  • The 6 main sectors to map

    1. SUN: the sun's path in winter (low, south-east to south-west) vs summer (high, east to west), identify the areas of full winter light for greenhouses and fruit trees, the areas of summer shade for cool crops. 2. PREVAILING WINDS: North/North-East cold and dry, South-West damp and mild in France (regionally variable). 3. WATER: runoff, springs, water table, flood zones. 4. FIRE (dry climate): potential direction of arrival, fire-brigade access. 5. VIEWS: beautiful ones to amplify (by framing with plants), ugly ones to hide. 6. NOISE and POLLUTION: road, noisy neighbour, polluted axis.

  • Method: the sector map

    On a sketch of the site seen from above, draw “pie slices” from the centre of life. Each slice represents the angle of arrival of a sector. The winter sun arrives in a narrow angle from the south-east to the south-west. The prevailing winds in a wide angle from the west. Driving rain as curved arrows. This map is cross-referenced with the map of zones to decide where to put what.

  • The design work: amplify or block

    AMPLIFY: capture the winter sun with a greenhouse against the south wall, a reflective terrace. Capture runoff with a swale on the contour line. Capture the night coolness for passive ventilation. BLOCK: a windbreak hedge upwind of sensitive crops. Its range of action is measured in multiples of its own height (H): the sheltered zone classically extends up to about 20 H downwind, but “sheltered” does not mean calm, because at the very end the wind is slowed only by about 20%. The strongest slowing happens near the hedge, around 4 H. A 4 m hedge therefore has an influence up to ~80 m, in a decreasing way. Stone walls to block noise. Filtering vegetation strips against road pollution. Sources: Bill Mollison, Permaculture: A Designers' Manual, Tagari, 1988; Patrick Whitefield, The Earth Care Manual, Permanent Publications, 2004.

Watch out for

  • • Prevailing winds vary regionally and locally: a sheltered site may have different winds from the regional context. Observe for a year before planting a hedge.
  • • The functions of a sector can change over time: a neighbour builds, a tree falls, a road is created. The design is never fixed.

Sources

  • Mollison, B. (1988). Permaculture: A Designers' Manual. Tyalgum : Tagari Publications.
  • Whitefield, P. (2004). The Earth Care Manual: A Permaculture Handbook for Britain and Other Temperate Climates. East Meon : Permanent Publications.