Multipurpose Trees in agroforestry
The term “multipurpose tree” refers to all woody perennials that are purposely grown so as to provide more than one significant contribution to the production or service functions (food, fodder, fuel, timber, shelter, shade, land sustainability) of the land use system they implement.
Accordingly, a tree which will serve more than one purpose is a multipurpose tree. A single tree may serve more than one purpose. For example, Gliricidia sepium that in addition to green manure provides fuel, fodder and acts as live fence.
Characteristics of MPTs suitable for Agroforestry
· Adaptability to local climatic conditions.
· Ease of establishment from seeds and seedlings.
· They should have a low crown diameter to bole diameter ratio.
· They should be light branching in their habit.
· They should tolerate relatively high incidence of pruning.
· Deep thrusting tap root system and few and shallow lateral roots (or prunable).
· Their phyllotaxies should permit penetration of the light of the ground.
· Good Coppicing ability.
· Effective nutrient recycling.
· Multiple uses: food, feed, firewood, construction materials and other products and service (shade, shelter etc.)
· Minimal competition with shallowly rooted annual crops.
· Small leaflets readily detached when dried and quickly decomposed when used as fertilizer.
· A high proportion of leaves to secondary branches.
· Good tolerance for drought, low fertility and others.
· Freedom from pests and diseases.
· Not compete for moisture, space and air.
· Ability to fix atmospheric nitrogen.
· Supply nitrogen in the soil.
· Have thin and erect leaves.
· Maintain proper ecosystem.
· Non-allelopathic effects on arable crops.
· Easy to propagates and prolific seed producer.
Benefits/Services from MPTs
The benefits from MPTs can be summarized as follows:
1. Human food from trees (fruits, nuts, leaves etc.).
2. Livestock feed from trees.
3. Improved nutritional status of food and feed crops through:
a) Nitrogen fixation.
b) Access to greater volume of soil nutrients through deep rooting trees.
c) Improve availability of nutrient associated with higher cation exchange capacity and organic matter levels.
4. Increased crop production through soil and water conservation.
1. Firewood for direct combustion.
2. Pyrolytic conversion products (charcoal, oil, gas etc.)
3. Produces gas from wood or charcoal feed stocks.
4. Ethanol from fermentation of high carbohydrate fruit.
5. Methanol from destructive distillation or catalytic synthesis processes using woody feedstock.
6. Oils, latex, other combustible saps and resins.
1. Building materials for shelter construction.
2. Shade trees for humans, livestock’s and shade loving crops.
3. Windbreaks and shelter belts for protection of settlements, crop land and pastures.
4. Living fences.
D. Raw materials for processing
1. Wood for a variety of craft purpose.
2. Fiber for weaving industries.
3. Fruits, nuts etc for drying another food processing industries.
4. Tannins, essential oil, medicinal ingredients.
1. Direct cash benefits from sale of above listed production.
2. Indirect cash benefits from increased production of crops or livestock.
F. Long term benefits
1. Increased crop productivity.
2. Sustain crop productivity.
3. Improve environmental condition.
4. Improve socioeconomic condition.