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close this bookAgroforestry In-service Training: A Training Aid for Asia & the Pacific Islands (Peace Corps, 1984)
View the document(introduction...)
View the documentAcknowledgments
View the documentExecutive summary
View the documentForeword
View the documentComments and recommendations
View the documentTraining program goals and objectives
View the documentAgenda for agroforestry workshop
close this folderTraining sessions
View the documentDay one
View the documentDay two
View the documentDay three
View the documentDay four
View the documentDay five
View the documentDay six
View the documentEvaluation of training workshop
close this folderAppendices
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View the documentAppendix A: List of workshop participants
View the documentAppendix B: Workshop technical staff
View the documentAppendix C: List of international organizations for resource assistance
close this folderAppendix D: New directions in agroforestry: The potential of tropical legume trees
close this folder1. Selection of legume trees for agroforestry
View the document(introduction...)
View the documentAgroforestry working group
View the documentThe ecological role of trees in sustainable agroforestry: A review
View the documentThe special role of legume trees in sustainable agroforestry
View the documentBases for selection of legume trees for agroforestry
View the documentCharacteristics of some nitrogen-fixing legume trees
View the documentAppendix: Simple field methods to determine or assess soil acidity or alkalinity
close this folder2. Initial tasks in agroforestry projects
View the document(introduction...)
View the documentSocioeconomic surveys
View the documentMotivating local people to participate in agroforestry
close this folder3. Sustained outputs from legume-tree based agroforestry systems
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View the documentFood crop production in agroforestry
View the documentFood production from legume trees
View the documentFodder production from legume trees
View the documentFuelwood production for domestic use
View the documentFuelwood production for commercial use
View the documentTimber production in agroforestry
View the documentAppendix: A-frame: A simple tool for establishing contour hedges
View the documentRecommended references
close this folder4. Economic evaluation of agroforestry projects
View the documentThe need for economic evaluation
View the documentFactors in economic evaluation
View the documentEconomic evaluation techniques
View the documentA simplified example
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close this folderAppendix E: Nitrogen-fixing tree resources: potentials and limitations
View the document(introduction...)
View the documentThe balding of the tropics
View the documentGenetic resources for N2-fixing trees
View the documentImportant genera of N2-fixing trees
View the documentWood and fuelwood
View the documentGreen manure and nurse trees
View the documentForage
View the documentUniversity of Hawaii trial network for N2-fixing trees
View the documentResearch imperatives
View the documentReferences
close this folderAppendix F: Production of fuelwood and shall timber in community forestry systems¹
View the document(introduction...)
View the documentIntroduction
View the documentWood yields and land area requirements
View the documentPlantation establishment and management
View the documentSustainable plantation management
View the documentConclusion
View the documentLiterature cited
close this folderAppendix G: Leucaena as a fallow improvement crop: A first approximation¹
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View the documentIntroduction
close this folderSection I: Fallow crop improvement
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View the documentLeucaena as a fallow improvement crop
View the documentConclusions
View the documentSection II: A description of a Leucaena based fallow system used on the island of Mindoro, Philippines
View the documentBibliography
View the documentAppendix H: Nitrogen fixing trees: general information
View the documentAppendix I: Establishment and management of NFT plantations
View the documentAppendix J: Evaluation
View the documentAppendix K: Chart on results of workshop evaluation

Important genera of N2-fixing trees

The 18,000 species of legumes (Family: Leguminosae) include the vast majority of important N2-fixing trees and shrubs, many of which are in the predominantly woody subfamilies Mimosoideae (2800 spp.) and Caesalpinioideae (2800 spp.). Relatively few of the 12,000 species of Papilionoideae are arboreal, but some of these are of great economic importance. A high proportion of the tested mimosoids (92%) are able to fix N2, contrasted with the papilionoids (94%) and the caesalpinioids (34%). A few nonleguminous tree genera also fix N2, notably the temperate genus Alnus and the tropical Casuarina (Stewart, 1967; see p. 427).

Leguminous trees produce some of the outstanding luxury timber of the tropics (NAS, 1979). Notable among these are the papilionaceous genera Dalbergia (rosewood), Perocopsis (African teak), Pterocarpus (narra), and the caesalpinioid genus Intsia (ipil, Moluccan ironwood). Other important timbers include the mimosoids Acacia, Lysiloma, Parkia, and Samanea. Preferred timber species often exceed 30 m in height and are of slow-to-intermediate growth rates. With their high intrinsic value, such trees might wisely be interplanted at wide spacing (e.g., 100/ha) in plantations of fast-growing legumes, as a long-term investment.

The legume trees best known as ornamentals, offering striking displays of color when in flower, are predominantly in the Caesalpinioideae, many of which do not fix N2. The ornamental legumes include:

Caesalpinioideae: Amherstia, Barklya, Bauhinia, Brownea, Caesalpinia, Cassia, Colvillea, Delonix, Peltophorum, Saraca, and Schotia.

Mimosoideae: Calliandra, Samanea.

Papilionoideae: Butea, Erythrina, Sabinea, Sophora.

Several tree legumes provide valuable gums (Acacia spp.) and the pods of several species are excellent human foods, including:

Caesalpinioidae: Ceratonia (carob), Tamarindus (tamarind).
Mimosoideae: Inga. Parkia.

The following discussions will focus on legume trees with special significance as sources of energy or green manure. As a generalization, most fast-growing legume trees are mimosoids. Genera to be considered in the discussions of energy and green manure are listed below, together with their approximate number of species:

Caesalpinioideae: Acrocarpus (3), Cassia (600), Schizolobium (5)

Mimosoideae: Acacia (600), Albizia (100), Calliandra 9100), Desmanthus (40), Mimosa (450), Parkia (40), Pithecellobium (200), Prosopis (44), Samanea (1).

Papilionoideae: Dalbergia (250), Erythrina (100), Flemingia (35), Gliricidia (10).