Permaculture Designers Manual
CHAPTER 10 –
THE HUMID TROPICS IN PERMACULTURE
Section 10.14 –
Humid Tropical Coast Stabilization and Shelter-belts in Permaculture
If we presume a fairly delicate sandy coastline, then we need to build a complex stable assembly from the wave break to 10-20 m inland.
The natural profile of undisturbed beach vegetation is that of a convex profile into the wind and these uncut shores are very stable.
TROPICAL HEDGEROW AND WINDBREAK
Deliberately mixed hedgerow is a preoccupation, skill and literature of the temperate zones (as these were the first to suffer enclosures of common lands), but the rape of the tropics has now proceeded so far and fast that pioneer hedgerow is a priority theme for tropical coasts and hill country.
Due to ideal growing conditions in the climate, if not the soil, hedgerows quickly establish.
A classical hedgerow for the tropics is given below.
Well-tried procedures are as follows:
Cultivate, manure and place drip line along a hedgerow site and set out (concurrently) a row of:
- Tall grasses or clump bamboo; Pennisetum is usual.
- Quickset cuttings of Erythrina fusca or Jatrophe.
- Seedlings of Leucaena or Acacia.
- Occasional palms as seedlings, preferably those with spiny trunks or mid-ribs.
The results can be as in Figure 10.48.
This is for field conditions. When first setting small orchard crop such as citrus or avocado (both wind tender), first cast up an earth ridge system and plant Pennisetum hedges every 30m (100 feet) crosswind and (if possible) cross-slope.
This may result in a series of parallel lines (if wind and slope coincide) or a diamond pattern (wind at an angle to slope) or a series of squares (wind and slope at right angles).
Pay particular attention to the top of ridges in wind-prone areas.
As the young orchard grows, the Pennisetum at 30m shelters it.
Every second row of Pennisetum can be combined with Leucaena and every third and every ridge row with Acacia and palms.
The evolutions follow: Later, the inner rows can be removed as mulch.
Complicating the Hedgerow
Tomato trellis can be placed on Leucaena and passion fruit on most trees.
Mango itself is a good windbreak, Eugenia can replace some Leucaena and we are on the way to a mixed hedgerow for wild life, domestic forage and food in the tropics.
I would never neglect a bamboo clump as a source of structural field material and effective windbreak.
The cross-slope ridges early established become long-term soil and water traps and accumulate mulch for later evolutions.
These are a feature of the Tropical Crops Materials Centre on Molokai and there, one can see their uses and long-term evolution (under cultivation) into terraces of undoubted stability, as in Figure 10.8.
Roads should be provided with concrete or stone fill at “X”, the downhill side of the mounds.
Permanent roads can be made after the terraces are formed.