Overstory #16 - Multipurpose Trees

Multipurpose Trees: Key Components in Agroforestry

While all trees can be said to serve several purposes, such as habitat, shade, and soil protection, some trees really stand out in their usefulness. Such trees are called "multipurpose trees"-- trees with the ability to provide numerous products and perform a variety of functions in farming or forestry. Multipurpose trees can be integrated with farming and forestry to improve yields, diversify products, increase economic resiliency, and improve farm viability and sustainability in the long-term.

Multipurpose trees are key players in supporting an overall farm system. When you plant a multipurpose tree, a number of needs and functions can be fulfilled at once.

Examples of multiple functions and products to look for in a tree:

• wind resistance (to use as a component in a windbreak)
• erosion control
• soil fertility improvement
• nitrogen fixation
• shade
• wildlife habitat
• mulch or green manure
• pest control
• animal fodder
• living fence
• fuel wood
• food (fruit/vegetables/root/shoot/oil)
• medicinal uses
• tannin/dyes/soaps/cosmetics
• bee forage for honey
• crafts, carving
• timber

When choosing a species for a particular purpose, consider the multiple uses and functions the species can provide. For example, while there may be many species that are wind-strong enough to suit your needs for windbreak, you may also ask, which species can I choose that are wind strong AND have other uses for this farm? Your windbreak may be able to serve as a long-term investment for timber, a short-term supplier of pole or firewood, a living fence, or possibly even a supply of fruit. (There are many other considerations in designing a windbreak, which will be featured in a future Overstory Online).

An added benefit of using multipurpose trees is that they can provide a certain amount of insurance in the event of a primary crop failure or market fluctuation. An emphasis on multipurpose trees in your planting creates resources that can allow the farm to be diversified and productive in the long-term, even if environmental or market conditions shift from the primary crops.

Examples of Some Outstanding Multipurpose Trees

Neem (Azadirachta indica): Powerful insecticidal and medicinal properties in seed, leaf, and bark; also food (leaves), timber, windbreak component (SEE NEEM HIGHLIGHT BELOW)

Jackfruit (Artocarpus heterophyllus): Edible fruit, seeds, and young leaves; leaves used for animal fodder; bark used for dye; medicine; timber; windbreak component

Ipil Ipil or giant haole koa (Leucaena leucocephala): Fixes nitrogen, provides mulch and organic matter, windbreak component, fodder, food, fuelwood, seeds used in jewelry and crafts

Coconut (Cocos nucifera): nut, purified water (inside nut), timber, fuel, crafts (fronds, nut, husk and wood), housing thatch, wind protection, also used traditionally in the Pacific to shade cattle and taro.

Mango (Mangifera indica): fruit, medicine, leaves used as mulch, wood used as timber, windbreak component.

Peach palm (Bactris gasipaes): fruit, heart of palm, durable craft wood.

Tamarind (Tamarindus indica): Shade, fruit, light timber, medicinal uses.

Madre de Cacao (Gliricidia sepium): Nitrogen fixing, for shade, fodder, mulch, living fence.

The Neem Tree (Azadirachta indica): A Classic Multipurpose Tree

The neem tree is a widely adaptable multipurpose tree, traditionally popular in India, Africa and Asia. Neem is now receiving international attention in agriculture and forestry. Neem thrives in subhumid and arid conditions, and can grow in areas with 500 mm (20 inches) of rainfall or more without irrigation. It can reach a height up to 25m (90 ft), with a spreading crown. It is salt tolerant and survives in areas with depleted soils due to its extensive root system which extracts deep soil nutrients.

Neem has these virtues:

• A potent insecticide can be extracted from neem seeds, leaves and bark which controls certain pests while leaving beneficial insects relatively unaffected.
• In the mahogany family, neem makes an excellent termite-resistant timber similar in quality to mahogany.
• Traditionally, neem is known for its medicinal qualities; its bark, leaves, and roots have numerous applications in traditional healing.
• Its leaf litter enriches the surface layer, improving local soil conditions.
• The bitter leaves and flowers are edible, used as a pot herb.
• Dried leaves are stored with grains to prevent pests.
• Neem seed cake, the pulpy residue left after extracting the oil from neem seed, is used in India to control nematodes and soil pests in crops such as citrus. The seed cake is also thought to enhance nitrogen fertilizers.
• In Africa, neem is known as the "toothbrush tree," as the twigs are chewed by people for dental hygiene.

A Source for Neem Trees

Looking for a source for quality neem seedlings? Future Forests Nursery offers select varieties of neem in seedling form, grown for forestry and agroforestry. For more information visit the web site Future Forests Nursery, LLC or email trees@agroforester.com

About the Authors

Kim M. Wilkinson is the Education Director for Permanent Agriculture Resources and editor of The Overstory. She has B.A. degrees in Anthropology and Ecology from Emory University.

Craig R. Elevitch is an agroforestry specialist with more than ten years of public and private sector experience in tropical agroforest and forest management. He has a M.S. degree in Electrical Engineering (Dynamical Systems) from Cornell University.

Related Editions to The Overstory

• The Overstory #59--Choosing Species for Timber Production and Multiple Benefits
• The Overstory #54--The Agroforester's Library, Part Two--Species
• The Overstory #32--Multipurpose Windbreaks
• The Overstory #31--Tree Domestication
• The Overstory #30--Bamboos in Agroforestry
• The Overstory #19--Selected Tree Seed
• The Overstory #6--Multipurpose Palms
• The Overstory #4--Nitrogen Fixing Trees