Introduction to the Humid Tropics in Permaculture

Permaculture Designers Manual




Section 10.1 –

Introduction to the Humid Tropics in Permaculture

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The subsets or climatic zones included in this Module specifically exclude arid tropics, which are included in Chapter 11, together with cold arid areas.

As plants and techniques do not split off neatly into climatic areas, the following three Chapters (C10 – The Humid Tropics, C11 – Dryland Strategies, C12 – Humid Cool to Cold Climates)  should be read in total for any one site.

A subtropical site, for instance, can have quite severe frosts, cold winds, torrential summer rains and 7-9 months of drought, so that it needs the strategies, earthworks and species suited to temperate, arid and tropical humid climatic regimes.

However, it is true that soils and climatic characteristics do dictate the specific broad design responses.

Some special topics or the humid tropics are those of soils, mulch sources, planning for polyculture and appropriate house construction, each of which is given a unit.

In the wet tropics, heat and high rainfall would leach most mobile nutrients from soils, except for the biomass of the great variety of plants, which contain 80-90% of the available nutrients.

Humus is an essential soil fraction and humus creation must be given considerable emphasis as prerequisite to sustainability.

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Inappropriate strategies are those of bare-soil cultivation or intensive clearing and burning in short cycles (less than 8 years or so) for cropping.

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Appropriate strategies involve complex and multi-storied plant systems designed to yield basic staples, create mulch and preserve soil nutrients.

James Fox in Harvest of the Palm (1977) has been one of the few who have analyzed the social changes and loss of self-reliance following the abandonment of ancient and balanced palm polyculture in Indonesia.

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Ancient tropical civilizations have been noted for their stability, indicating that sustainable land use patterns are an essential prerequisite for social harmony.

The Food and Agriculture Organization of the United Nations ( FAO) admits to failure in transferring mechanized monoculture systems (barely sustainable in temperate moist areas) to fragile African or tropical soils.

It is a wonder that this was tried at all in modern times; the clearing and cultivation of tropical soils has for decades proved disastrous and most ecologists would have predicted this failure by the early 1950’s.

Complex perennial fodder and food systems are known to be stable, but are not as yet part of the officially funded agricultures from such sources as the World Bank.

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Deserts present even more fragile systems and need greater skills to stabilize and manage. The most inappropriate advisor is an agriculturalist trained in “modern” techniques.

What are needed are continuous local education of experienced people and a lateral transfer of their evolved skills. Emphasis in such education should range from an analysis of health and environmental problems to practical solutions, with sophisticated plant and animal technological assemblies adapted to local food preferences, nutritional needs and cultural requirements.

Romantic literature on the “easy” tropical life leaves out the skin cancers, rodent ulcers, dengue fever, filaria, malaria, chronic bowel and skin disease and the constant battle with rampant growth that is an everyday experience at Latitudes 0-25°.

That, and the pythons, ticks, termites, rain, mould and lethargy caused by heat exhaustion. With the increasing loss of atmospheric ozone, it is folly for fair or red-haired Europeans to expose bare skin to the tropical sun – a cause of skin cancer in Australia and “haole rot” (a form of fungal bleaching of the skin) in Hawaii.

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Humid heat induces a lethargy compounded by chronic illness in many populations. Waterborne and mosquito-transmitted diseases are almost impossible to totally control, given the aerial reservoirs of water developed by palms and bromeliads.

In houses, induced cross-ventilation and careful construction for mosquito control are essentials, as are plant systems based on a tree species polyculture; the two combine very well to reduce climatic extremes.

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We can largely emulate the tropical forests themselves in our garden systems, establishing a dominant series of legumes, palms and useful trees with a complex understory and ground layer of useful herbaceous and leguminous food and fodder plants; vines and epiphytes can complex this situation as it evolves.

In the wet-dry tropics, more open palm polyculture is appropriate; the excesses of heat, light and rain are best modified by an open canopy of palm fronds and the fern-like leaves of tree legumes.

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