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close this bookAbstracts on Sustainable Agriculture (GTZ; 1992; 423 pages)
Open this folder and view contentsAbstracts On Traditional Land-Use Systems
Open this folder and view contentsAbstracts on farming systems research and development
Open this folder and view contentsAbstracts on integrated systems
Open this folder and view contentsAbstracts on cropping system
Open this folder and view contentsAbstracts on agroecology
Open this folder and view contentsAbstracts on agrometeorology
close this folderAbstracts on agroforestry
View the documentAcknowledgements
View the document1. Tree products in agroecosystems: economic and policy issues.
View the document2. Sustainable use of plantation forestry in the lowland tropics.
View the document3. The palcazu project: forest management and native yanesha communities.
View the document4. Opportunities and constraints for sustainable tropical forestry: lessons from the plan piloto forestal, quintana roo, Mexico.
View the document5. The taungya system in south-west Ghana.
View the document6. Planning for agroforestry.
View the document7. Sowing forests from the air.
View the document8. Agroforestry pathways: land tenure, shifting cultivation and sustainable agriculture.
View the document9. Food, coffee and casuarina: an agroforestry system from the Papua New Guinea highlands.
View the document10. Agroforestry in africa's humid tropics - three success stories.
View the document11. Agroforestry and biomass energy/fuelwood production.
View the document12. Regeneration of woody legumes in Sahel.
View the document13. Medicines from the forest.
View the document14. Potential for protein production from tree and shrub legumes.
View the document15. Agroforestry for sustainable production; economic implications.
View the document16. Living fences. A close-up look at an agroforestry technology.
View the document17. Homestead agroforestry in Bangladesh.
View the document18. Guidelines for training in rapid appraisal for agroforestry research and extension.
View the document19. Erythrina (leguminosae: papilionoideae): a versatile genus for agroforestry systems in the tropics.
Open this folder and view contentsAbstracts on homegardens
Open this folder and view contentsAbstracts on seed production
Open this folder and view contentsAbstracts on plant protection
Open this folder and view contentsAbstracts on water management
Open this folder and view contentsAbstracts on soil fertility
Open this folder and view contentsAbstracts on erosion and desertification control
Open this folder and view contentsAbstracts on potential crops for marginal lands

7. Sowing forests from the air.

National Academy Press, Washington, D.C., ISBN 80-83796, Third Ed., 1986, 57 p. + annex

This report discusses reforestation in which the seed is broadcast from a plane or helicopter. It relies mainly on experiences in Australia, New Zealand, Canada, and the United States.

Sowing forest seed directly on the site to be forested is known to foresters as direct seeding, broadcast seeding, or broadcast sowing. The availability of chemicals for coating seeds to repel birds, rodents, and insects has made this a practical and more reliable method of reforestation.

In many parts of the world, deforestation has reached critical proportions. Africa, Asia, and Latin America have vast areas of once-forested land that is now denuded. Many have been left largely unplanted.

These enormous areas of virtually unproductive land are increasing.

Traditional revegetation methods should be applied more extensively, but the time also seems right for examining alternative methods.

Dropping seed from planes or helicopters is a well-known and well-established technique for sowing pastures as well as agricultural crops such as soybeans, wheat, and rice. Forests have also been established in this way. However, aerial seeding of forests is largely unappreciated, even by most foresters.

When conditions and species are right, and seed supplies sufficient, aerial seeding could be an important technique for reforesting large areas. It is easy to organize and seems well suited for reforesting sites that have rough terrain, debris, or difficult access. If it can be developed for sites and objectives in developing countries, aerial seeding could offer opportunities for vastly accelerating their reforestation programs.

Aerial reforestation is not a replacement for planting seedlings by traditional methods. It is best considered as a potential complement to conventional planting and to natural seeding, an additional tool for foresters to use when the needs, sites, and species are appropriate.

Sowing tree seed directly in the field is an old technique, but it was little used until the development of repellents to protect seed from insects, rodents, and birds.

It was learned that an additional coating of commercial insecticide would guard the seed against insects and rodents. These findings signalled the beginning of large-scale aerial seeding of forests in USA.

New Zealand demonstrates its success. Some of these forests have been established despite seemingly adverse conditions - for example, on steep slopes and on overburden from strip mines.

Aerial seeding is unproven in the tropics. The panel's purpose is not to recommend it over conventional reforestation techniques but to suggest trials of aerial seeding as a possible supplementary tool.

This book is not a textbook nor a practical guide to aerial seeding: details of the operations and techniques can be found in the selected readings. The purpose is to show administrators and foresters that this fast and often economical technique can be successful on appropriate sites, at least in temperate climates. The authors hope that the report will stimulate trials with, and research into, direct seeding (with or without the use of aircraft). In particular, trials are needed in the tropics where deforestation is most severe.

Aerial seeding presents many challenges for researchers, especially those in developing countries. While technology and techniques are developed and available, they are yet to be tested and adapted for use in those Third World areas now suffering devastating deforestation.

Because experience with aerial seeding of forests in the humid tropics is limited, little is known about predators and the best species to sow.

Aerial seeding could be an expensive failure unless small-scale trials show that direct seeding can be successful for the given species and sites.

Initially, these trials do not require use of aircraft. It is necessary only to broadcast a small amount of seed (pretreated, if necessary) on a small patch of the area being tested with conventional tree-planting methods.

The existing knowledge on seed coating and pelleting should be reviewed.

Successes and failures are reported in different situations.

Seeds can be targeted accurately (often within a meter or two). Thus direct seeding might prove feasible for filling in the widely scattered breaks in the forest left by slash-and burn farmers with useful species that best protect the vulnerabale soil.

1168 92 - 7/82


Review, tropics, subtropics, developing countries, land-use systems, land-tenure, shifting cultivation, sustainable agriculture, marginal lands, fallows, alley cropping, intercropping, trees, agropastoral systems, mixed farming


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