Multipurpose Trees (MPTs) and Other Agroforestry Species

Abstract

The multipurpose tree (MPT) is a term that is used almost exclusively in tropical agroforestry. In a general sense, the perennial and taller plant components of agroforestry systems (AFS) are referred to as trees, but the MPTs are woody species that are deliberately kept and managed for more than one preferred use, product, or service. Such species, relatively underutilized in commercial forestry and conventional agriculture are the distinctive components of most AFS in the tropics. Several of them are designated by single-purpose-sounding terms such as fodder trees, fruit trees, fuelwood species, and other special-purpose trees, but they provide multiple products and services. The MPTs have been a major thrust area of research in tropical agroforestry with emphasis on the collection, synthesis, storage, and dissemination of information at various levels (global, national, regional, etc.). The World Agroforestry Agroforestree database and the Agroforestry Species Switchboard launched in 2019 (http://www.worldagroforestry.org/products/switchboard/) document more than 26,000 plant species across 24 web-based information services that support agroforestry research. Several other global and regional databases are available and are listed in the chapter. The chapter also includes (Annexure 13-I) short profiles of about 60 commonly used MPTs in tropical AFS, with illustrative photographs of many. In addition, numerous other species that are important components of various AFS are designated as “lesser-known” or “less-prominent” taxa that include woody as well as non-woody, and seasonal or perennial species; Annexure 13-II includes profiles and photographs of ten such species. Brief notes are also included of a few unique high-value species traditionally grown in agroforestry combinations and are under the threat of extinction because of overexploitation for their high-value products.

Appendices

Appendices

1.1 Appendix I: Short Descriptions of Multipurpose Trees and Shrubs (MPTs) Commonly Used in Agroforestry Systems

These descriptions include essential information on the taxonomy (such as family/sub-family), ecology (distribution and ecological adaptation), morphology (plant characteristics), silviculture (management), and main uses of each species. Other relevant information is given under the sub-heading "Comments". Photographs of some of the species are also included; moreover, references are made to agroforestry-system photographs in other chapters in which the species being profiled appears prominently.

The information has been collated from several sources, mentioned in Section 13.1, as well as from field experience, and is thus of a general nature. For any species, deviations from these general characteristics can be expected under diverse field conditions. Hundreds of MPTs exist in agroforestry systems around the world; only about 50 are included here. These were not selected based on any special criteria other than the relative prominence of the species in the agroforestry systems that are common in one or more geographical regions.

The botanical names of some of the species have changed recently. As much as possible, the present, correct names and the synonyms are given using the ICRAF’s Agroforestree database (Orwa et al. 2009), Plant List Version 1.1 (www.theplantlist.org), and the Invasive Species Compendium (CABI 2019). There are such name changes in plant families too: the taxonomy of the family Leguminosae, an important family to which many MPTs belong, also known as Fabaceae, is in a process of transition: Caesalpinioideae, Mimosoideae, and Papilionoideae, the three sub-families of Leguminosae, are being elevated to the status of families as Caesalpinaceae, Fabaceae or Papilionaceae, and Mimosaceae, respectively. Similarly, Palmaceae, or the palm family, is now correctly known as Arecaceae. Many of the species are known by several local names in different places; because of the multiplicity of these local names, they are not mentioned here.

• Acacia mangium Willd.

• (Fabaceae; Mimosoideae)

Origin and Distribution:

Australia, Papua New Guinea; introduced to several Asian countries.

Ecology:

Occurs in moist lowland tropics (1500–3000 mm annual rainfall, from sea level to 800 m altitude) on acidic soils; usually along streams and on well-drained flats and low ridges.

Plant Characteristics:

Evergreen single-stemmed tree or shrub; 25–35 m height and 60 cm diameter; erect, stately habit (Figure 13.A.I.1; See Chapter 11, Figure 11.6.2); propagated by seedlings or cuttings; fast growth; N₂ fixing; coppices (only young trees); shade-intolerant.

Figure 13.A.I.1

Acacia mangium Unlike most other species of the genus Acacia, A. mangium is fast-growing and adapted to humid lowlands of South and Southeast Asia. (Photo: BM Kumar)

Main Uses:

Germinating seeds cooked and eaten as a vegetable; timber (0.65 sp. gr.); fuelwood and charcoal (4800–4900 kcal kg^-1); watershed protection; firebreaks; ornamental; fodder.

Comments:

Ability to grow on a wide range of sites makes it popular for reforestation; plantations quickly attain canopy closure, which is ideal for combatting Imperata grass; pioneer species.

• Acacia nilotica (L.) Willd. ex Del.

• (Fabaceae; Mimosoideae)

Synonyms:

Vachellia nilotica (L.) P.J.H.Hurter & Mabb.; Mimosa nilotica L.

Origin and Distribution:

Native to semiarid Africa; introduced to Indian sub-continent.

Ecology:

Dry tropics at low altitudes including areas of low and unpredictable rainfall and high temperatures; prefers alluvial soils, but grows well on heavy clay, as well as poor soils.

Plant Characteristics:

To 20 m, but usually less; can be a shrub in very unfavorable conditions; flat or umbrella-shaped crown (Figure 13.A.I.2); propagated by direct seeding, seedlings, and root suckers; N₂ fixing; coppices; strong light demander.

Figure 13.A.I.2

Acacia nilotica trees on farmlands in Chattisgarh, Central India, with rice as the understory crop and Sesamum indicum, a short-duration (90 days from sowing to harvesting)oilseed crop on the bunds(risers) between plots. The rice is planted in standing water in a puddled field; when the rains subside, the water is drained off. The tree withstands some waterlogging as well as dry conditions. (Photo: PKR Nair)

Main Uses:

Fuelwood and charcoal (sp. gr. 0.67–0.68; calorific value: 4500–4950 kcal kg^-1); wood is termite-resistant and is employed for a variety of farm uses; fodder (pods, leaves); tannin and gum; land reclamation.

Comments:

Extremely thorny; subject to wood borer attack; thrives under irrigation; requires weeding in early establishment stages. Commonly known as babul or gum arabic tree. Several subspecies have been reported.

• Acacia senegal (L.) Willd. (The Gum Arabic Tree)

• (Fabaceae; Mimosoideae)

Origin and Distribution:

Native to Africa (Senegal to Sudan), Pakistan, and India; introduced to Egypt and Australia.

Ecology:

Found in dry tropics (200–800 mm rainfall, 8–11 dry months/year) at 100–1700 m altitude (Figure 13.A.I.3); grows on poor soils, but waterlogging not tolerated.

Figure 13.A.I.3

Acacia senegal, the gum Arabic tree, a common species on farms and landscapes throughout the drylands of subSaharan Africa. (Photo: ICRAF/World Agroforestry)

Plant Characteristics:

To 13 m, but a shrubby habit is common; many geographical races; propagated by direct seeding and seedlings; competes well with weeds; N₂ fixing; coppices.

Main Uses:

Fuelwood (up to 5 m³ ha^-1 yr^-1); gum arabic; local construction wood; food (seeds); fodder (pods, leaves); erosion control and soil rehabilitation; dune stabilization.

Comments:

Four varieties are recognized: senegal, kerensis, rostrata, and leiorachis; major component of agroforestry systems in the geographic region to the south of the Sahara stretching from West Africa to East Africa.

• Adansonia digitata L. (The African Baobab Tree)

• (Bombacaceae)

Synonyms:

A. bahobab L.; A. baobab Gaertn.; A. integrifolia Raf.; A. scutula Steud.; A. situla (Lour.) Spreng.; A. somalensis Chiov.; A. sphaerocarpa A.Chev.; A. sulcata A.Chev.; Baobabus digitata (L.) Kuntze; Ophelus sitularius Lour.

Origin and Distribution:

Widely distributed across continental Africa; exotic ranges include the Caribbean, parts of tropical South America, the Indian subcontinent, and East Asia

Ecology:

Occurs in thorny, low altitude woodlands in the arid and semiarid African savannahs (Figure 13.A.I.4); resistant to fire, termite, and drought; prefers a high-water table, but sensitive to waterlogging; mean annual rainfall: 100–1500 mm.

Figure 13.A.I.4

Adansonia digitata, the baobab tree, a distinct tree species on the African landscape (Stock photo)

Plant Characteristics:

A large, round canopied tree with a swollen trunk, 10–25 m high, 200–600 cm diameter at maturity; initial fast growth; lives for >1000 years; propagated mainly by seeds (need pre-treatment), but stem cuttings and grafts are also common.

Main Uses:

Seeds, leaves, roots, flowers, fruit pulp, and bark are edible; leaves eaten fresh or dried are the main source of food and folk medicine in Africa; wood is light but used for handicrafts; firewood; fodder; fiber bark; apiculture; part of African folklore and traditions.

Comments:

Pollarded or lopped to stimulate foliage production; several phytochemical constituents with medicinal properties have been identified, including vitamin C, steroids, flavonoids, epicatechin, campesterol, tocopherol, adansonin, and amino acids.

• Ailanthus triphysa (Dennst.) Alston

• (Simaroubaceae)

Synonym:

Ailanthus malabarica DC.

Origin and Distribution:

An Asian and Australian rainforest tree species; occurs in South and Southeast Asia, Southern China, and Australia.

Ecology:

Found in the evergreen to semi-evergreen forest margins to 1000 m altitude in the humid tropics with annual rainfall > 2000 mm; light-demanding; well-drained light/sandy soils.

Plant Characteristics:

Medium to tall tree; forms a compact crown (Figure 13.A.I.5); attaining a height of 30 m; fast growing; propagation through seeds.

Figure 13.A.I.5

Ailanthus triphysa in Kerala, India. (Photo: BM Kumar)

Main Uses:

The wood, being light and comparatively soft, is preferred for match manufacture but also used for making boats, sword handles, spear sheaths, paper pulp, fuel, and charcoal. Stem cuttings yield a gum and the bark contains aromatic oils used in medicines and aromatics in India; widely used as live stakes for supporting black pepper (Piper nigrum).

Comments:

The compact crown and straight and self-pruning, cylindrical bole make it well suited for agroforestry systems.

Related Species:

Ailanthus excelsa Roxb., adapted to drier regions (500 – 2000 mm rainfall)

• Albizia lebbeck (L.) Benth.

• (Fabaceae; Mimosoideae)

Origin and Distribution:

Native to India and Myanmar (Burma); introduced to other parts of Asia, as well as Africa, the Caribbean, and South America.

Ecology:

Widely adapted to dry and moist tropics (500–2000 mm rainfall), up to 1600 m altitude on a variety of soils (including saline).

Plant Characteristics:

To 30 m; spreading, umbrella-shaped crown (Figure 13.A.I.6); moderately fast growth; propagated by seeds, seedlings, and root suckers; coppices; N₂-fixing.

Figure 13.A.I.6

Albizia lebbek (Shirish tree). (Photo: ICRAF/World Agroforestry)

Main Uses:

Fuelwood (high calorific value: 5200 kcal kg^-1; 5 m³ ha^-1 yr^-1 produced on 10–15 years rotation); fodder; furniture wood; erosion control.

Comments:

Roots close to soil surface; easily damaged by wind; promising species for silvopastoral systems; after establishment, bi-annual pollarding may produce significant biomass.

Related Species

• Albizia falcataria (L.) Fosberg: (see Paraserianthes falcataria (L.) Nielson)

• Albizia saman (Jacq.) F. Muell (See Samanea saman (Jacq.) Merr.)

• Alnus acuminata H.B.& K.

• (Betulaceae)

Synonym:

A. jorullensis H.B.K. (also 26 other synonyms).

Origin and Distribution:

Native to Central and South America.

Ecology:

Cool tropical highlands (2000–3000 m) with 1000–3000 mm annual rainfall on well-drained, fertile soils; neither drought- nor heat-tolerant; a fast-growing pioneer species that regenerates naturally in open, disturbed areas.

Plant Characteristics:

To 25 m or more; N₂ fixing; propagated by seed, seedlings, and root cuttings; coppices.

Main Uses:

Fuelwood (10–15 m³ ha^-1 yr^-1 in 20-year rotations; calorific value 4600 kcal kg^–1); timber (sp. gr. 0.36); watershed protection; soil improvement; silvopastoral systems.

Comments:

Competes poorly with weeds during establishment phase; good pasture found under trees.

Related Species

Alnus nepalensis D. Don - Native to the Himalayas, China, and India; introduced to Africa;

Cool tropical highlands (1000–3000 m) with 500–1250 mm annual rainfall; To 30 m (up to 2 m in diameter); fast-growing; N₂ fixing; propagated by seeds and seedlings; fuelwood (sp. gr. 0.32–0.37; calorific value 4357 kcal kg^–1); wood for boxes; symbiosis with nitrogen-fixing actinomycetes (Frankia); shade tree for large cardamom (Amomum subulatum) or Cinchona spp. in the Himalayan region (Figure 8.15).

• Artocarpus altilis (Parkinson) Fosberg (The Breadfruit Tree)

• (Moraceae)

Synonyms:

A. communis J.R.Forst. & G.Forst. and 12 other names.

Origin and Distribution:

Native to New Guinea and possibly the Moluccas (Indonesia) and the Philippines; pan-tropical distribution.

Ecology:

Tropical lowlands below 600 m; rainfall 1500–3000 mm; deep, fertile, well-drained soils; requires some shade when young; develops a compact, dense canopy under full sun.

Plant Characteristics:

Single trunked tree with spreading, evergreen canopy (Figures 7.23 and 7.54); fast growth under favorable conditions; propagated from root shoots or root cuttings by air-layering branches, or grafting; the plant exhibits great variability, ranging from seedless to true-seeded cultivars.

Main Uses:

Fruit a starchy staple; high in carbohydrates and a good source of vitamins and minerals; seeds are high in protein and low in fat; all parts have medicinal value in the Pacific and the Caribbean; wood is lightweight, and flexible; easy to work and for carving; firewood.

Comments:

An important component of agroforestry systems associated with many staple and non-staple crops; interplanted with small fruit trees or short-term fruit and vegetable crops; genetically diverse; several named varieties are clonally propagated in the Pacific islands.

• Artocarpus heterophyllus Lam. (The Jackfruit Tree)

• (Moraceae)

Synonyms:

Artocarpus brasiliensis Gomez, A. heterophylla Lam., A. maxima Blanco, A. philippensis Lam.,

Origin And Distribution:

Native to the rainforests of Malaysia and the Western Ghats of India; common in South and Southeast Asia, the Pacific islands, and parts of Africa.

Ecology:

Grows in a wide range of tropical and subtropical conditions; altitude up to1600 m; (mean annual rainfall 1000–2400 mm); prefers well-drained, deep soils; sensitive to waterlogging; tolerates drought (3–4 months); seedlings grow best in 30–50% sunlight.

Plant Characteristics:

Medium-sized evergreen tree; 8–25 m tall; fruit is the largest among cultivated plants (Figure 13.A.I.7); dense crown, conical in young and shaded trees; coppices well; propagated by grafts, cuttings and air layering or by seeds, which are recalcitrant.

Figure 13.A.I.7

Artocarpus heterophyllus: Stock photo

Main Uses:

Fruits are eaten fresh or preserved; nutritious seeds either cooked by boiling or roasted before consumption; fruit pulp and seeds medicinally important; foliage an excellent fodder; medium hardwood (sp. gr. 0.6–0.7) valued as construction wood and lumber; used for making furniture, cabinets and musical instruments; resistant to termite attack.

Comments:

One of the most significant components of tropical homegardens; being open pollinated, genetic variability is high.

• Azadirachta indica Adr. Juss. (The Neem Tree)

• (Meliaceae)

Origin and Distribution:

South Asia; introduced to many parts of Africa.

Ecology:

Dryland, low altitude tropics (50–1500 m, 130–1150 mm rainfall); on variable soils; does not tolerate waterlogging or salinity.

Plant Characteristics:

To 15 m; deep-rooted; evergreen except in periods of extreme drought (Figure 13.A.I.8); coppices well; early growth from coppice is faster than growth from seedlings; propagated by seeds, seedlings.

Figure 13.A.I.8

Azadirachta indica (the neem tree) in Mali, West Africa. (Photo: PKR Nair)

Main Uses:

Fuelwood (sp. gr. 0.68, high calorific value 6.94 kcal g^–1); construction wood and lumber; windbreak; oil (seeds); shade; soil improvement (leaves, seed residue after oil extraction); industrial chemicals; insect repellant and anti-pest properties; seeds and leaves contain azadirachtin, which is the principal active compound of neem-based pesticides.

Comments:

Seeds quickly lose viability; can become a weed; tolerates long dry periods; seedlings compete poorly with weeds.

• Bactris gasipaes Kunth.

• Peach palm (English); Pejibaye (Spanish); Pupunha (Portuguese)

• (Arecaceae)

Synonyms:

Guilielma speciosa Martius, G. gasipaes (Kunth) Bailey, G. utilis Oersted

Origin and Distribution:

Central and South America

Ecology:

Adapted to a wide range of ecological conditions including acid soils; most productive on relatively deep, fertile, well-drained soils at low to middle altitudes (<800 m); sensitive to waterlogged soils; can withstand relatively short dry seasons (3–4 months), if soils are not excessively sandy.

Plant Characteristics:

Typically, multi-stemmed (cespitose), although single-stemmed plants do occur (Figure 13.A.I.9); propagated by seeds, which are recalcitrant; asexually through offshoots and tissue culture, which are yet to develop on commercial lines; rapid juvenile growth.

Figure 13.A.I.9

Bactris gasipaes The peach palm(Pejibaye in Spanish and pupunha in Portuguese) in Belém, Pa, Brazil. (Photo: Charles Clement)

Main Uses:

Provides several nutritious staple foods; fruit pulp for direct consumption; flour for infant formula and baked goods; cooking oil; livestock feed; boiled mesocarp, with various seasonings, is a popular hors d’œuvre; heart-of-palm is an important commercial product; wood is hard and useful for construction.

Comments:

The only palm species with domesticated populations in the Neotropics; cultivated peach palm is genetically diverse with many landraces; a popular and promising tree for agroforestry systems.

• Borassus aethiopum C. Martius

• (Arecaceae)

Origin and Distribution:

Native to Tropical Africa; introduced to India and Southeast Asia.

Ecology:

Found in the subhumid to semiarid tropics (500–1150 mm annual rainfall) at altitudes up to 600 m on medium, loamy to heavy, clayey, soils; can withstand saline soils.

Plant Characteristics:

To 20 m; single-stemmed, straight, erect habit; evergreen; deep rooting; light-demanding; fire resistant; tolerates high temperatures; propagated by direct seeding and seedlings; seeds are recalcitrant.

Main Uses:

Fodder; edible leaves, fruits, and seeds; beverages from fruit pulp and milk; palm wine; oil; fuelwood and charcoal; poles and posts; timber for house construction; medicine; fiber; packaging material; cosmetics; intercropped with millets, peanut (Arachis hypogaea).

Comments:

Usually found in areas with a high water-table; wood is highly resistant to termite.

Related Species:

Borassus flabellifer L. (The Palmyra Palm; Figure 13.A.I.10). Native to the Indian subcontinent and Southeast Asia. Dry to moist tropical and subtropical climates, up to 800 m elevation. Adapted to a wide range of rainfall (250–5000 mm) and temperature conditions (0°–45 °C). Tall, single-stemmed evergreen palm, up to 30 m in height. As in coconut, tapping the palmyra palm inflorescence yields a nutritious sweet sap (toddy) that yields crude sugar (gur or jaggery), molasses, palm candy, and vinegar. Young solid or gelatinous endosperm of the seeds eaten fresh or in syrup; immature fruits pickled; all parts are important in folk medicines. Leaves used as thatch and for basket and mat making; A subsistence crop of the smallholders; intercropped as well as planted as a windbreak in the plains; used as a natural shelter by birds and bats in India.

Figure 13.A.I.10

The palmyra (Borassus flabellifer) palms in combination with various trees in Tamil Nadu, India. (Photo: BM Kumar)

• Bursera simaruba (L.) Sarg.

• (Burseraceae)

Synonyms:

Bursera gummifera L. and 12 others.

Origin and Distribution:

Native to tropical America; occurs in South and Central America, and to the north through the Caribbean to Florida.

Ecology:

Occurs in dry forests, but sometimes in wetter forests; altitudinal range up to 1000 m; mean annual temperature 18–25 °C; mean annual rainfall 800–3000 mm; prefers well-drained dry or moist soil with neutral and alkaline pH; but tolerates very alkaline and saline soils.

Plant Characteristics:

Medium-sized, deciduous tree; 18–30 m tall; large, spreading, crooked branches; drought-tolerant; propagated by seed.

Main Uses:

Leaves used as a tea substitute; branches are cut for cattle fodder; wood used as firewood or charcoal; also used for making plywood, tools, match sticks, toothpicks, cabinets, decorative articles and the like; yields balsam resin (used in South America as incense); bark medicinally important; ornamental tree; living fence.

Comments:

Commonly known as gum tree or turpentine tree; the aromatic resin is a natural insect repellent.

• Calliandra calothyrsus Meissner

• (Fabaceae; Mimosoideae)

Origin and Distribution:

Native to Central and South America; introduced in Indonesia, the Philippines, parts of Africa, the Caribbean and South Asia.

Ecology:

Occurs in moist tropics (2000–4000 mm annual rainfall, but can withstand droughts) at altitudes between 250–1800 m on a variety of soils (including infertile as well as clay-type soils); prefers light textured, slightly acidic soils; does not tolerate waterlogged and alkaline soils.

Plant Characteristics:

To 10 m; multi-stemmed shrub (see Figures 9.18, 11.5); N₂ fixing; coppices; established by direct seeding or seedlings; fast growing, easy to regenerate and manage.

Main Uses:

Fuelwood (5–20 m³ ha^-1 yr^-1); fodder (but high tannin may cause low digestibility); green manure; honey production; to rehabilitate erosion-prone areas.

Comments:

Competes well with weeds; an aggressive colonizer on disturbed sites; poor seed production (in some situations); insect pests attack flowers.

• Casuarina equisetifolia Forst. & Forst.

• (Casuarinaceae)

Synonym:

Casuarina littorea L.

Origin and Distribution:

Native to Australia; introduced to India, Pakistan, East, Central, and West Africa, West Indies, subtropical U.S., the Caribbean, and Central America.

Ecology:

Native to warm tropical coastal areas as well as semiarid regions (0–600 m, 1000–5000 mm annual rainfall); usually on sandy soils; tolerates both calcareous and slightly alkaline soils.

Plant Characteristics:

To 35 m; N₂ fixing (through association with actinomycetes); propagated by seedlings; rooted cuttings; coppices (only in some ideotypes); fast-growing (Figure 13.A.I.11).

Figure 13.A.I.11

Casuarina equisetifolia in Tamil Nadu, India. (Photo: BM Kumar)

Main Uses:

Fuelwood and charcoal (sp. gr. 1.0, one of the best in the world; calorific value 5000 kcal kg^–1); windbreak; timber for post wood; erosion control; dune stabilization.

Comments:

Can withstand waterlogging for a short period; wood yield 75–200 t ha^-1 on a rotation of 7–10 years with a 2 m-spacing between plants; salt-tolerant and wind-resistant; adaptable to moderately poor soils.

Related Species

Casuarina cunninghamiana Miq. Native to Australia; introduced to Africa, Argentina, the U.S., Israel, and China. Occurs in the cool tropics and subtropical areas (600–1100 mm annual rainfall) on acidic soils at elevations up to 800 m. To 35 m tall; relatively cold-tolerant; N₂ fixing (actinorhizal) with profuse nodulation involving Frankia, propagated by seedlings and root suckers; extensive, shallow roots; fast-growing. Fuelwood (sp. gr. 0.7; calorific value of ca. 5,000 kcal kg^–1); timber is durable and useful for flooring; shade; riverbank stabilization; windbreak. Can become a weed especially along canals and watercourses (declared as a weed in Florida); not adaptable to calcareous soils; susceptible to browsing damage.

• Cedrela odorata L. (The Spanish Cedar)

• (Meliaceae)

Origin and Distribution:

Native to Central and South America; introduced to the Caribbean, and parts of Africa and Asia; widely grown as a timber species in the Neotropics.

Ecology:

Adapted to the humid tropics (1000–3700 mm annual rainfall) at altitudes up to1900 m on medium, loamy to heavy, clayey, well-drained, deep soils with an acid to neutral pH; component of both primary and secondary evergreen to semi-deciduous lowland or lower montane rainforest in its native range; light-demanding and drought-hardy.

Plant Characteristics:

Large tree (up to 60 m tall) with an average of about 25 m; erect, single-stemmed, straight stem; evergreen; spreading canopy; shallow lateral roots; sometimes forms buttresses; fast-growing; does not tolerate waterlogging or flooding; can be propagated by direct sowing and seedlings.

Main Uses:

Timber for furniture and house construction; turnery; apiculture; fuelwood; produces attractively patterned veneer; medicinally important (bark, leaves, trunk, fruit, seeds); used for shade and as a windbreak in courtyard gardens and cacao and coffee plantations.

Comments:

Included in the IUCN Red List of vulnerable species; susceptible to insect damage; harvested wood is resistant to termites; tolerates seasonally waterlogged sites.

• Ceiba pentandra (L.) Gaertn. (The Kapok or Silk-cotton Tree)

• (Bombacaceae)

Origin and Distribution:

Found pantropically; origin believed to be Central America.

Ecology:

Found in the humid and subhumid tropics (750–2500 mm annual rainfall) at altitudes of 0–1600 m on light, sandy to medium, loamy, well-drained soils with a neutral pH; a pioneer species; mostly occurs in secondary forests.

Plant Characteristics:

Tall, deciduous tree with height to 60 m with an average of 30 m; single-stemmed with an open canopy (Figure 13.A.I.12); buttressed; thorny; deciduous during the dry season; propagated by seedlings and cuttings; light demanding; moderately drought resistant; fast growth (up to 1.2 m yr^-1) for first 10 years; susceptible to wind damage.

Figure 13.A.I.12

Ceiba petandra, the kapok or silk-cotton tree. (Photo: BM Kumar)

Main Uses:

Fiber or cotton from seed capsules; edible leaves; fodder; apiculture; medicine; cosmetics; the pressed cake is a cattle feed containing about 26% protein. The wood is very light, with a specific gravity of 0.25 g/cc; suitable for matchwood, light plywood containers, packing cases, fuelwood, etc.

Comments:

The floss derived from the inner fruit wall yields the kapok fiber – traditionally used for stuffing cushions, pillows, and mattresses, and for insulation, and as an absorbent material and tinder.

• Cordia alliodora (Ruiz et Pavon) Cham.

• (Boraginaceae)

Origin and Distribution:

Native to Central America.

Ecology:

A pioneer species found in a wide range of habitats; common in drier areas; occurs in moist tropical lowlands and midlands (up to 800 m, 750–2000 mm annual rainfall) on deep, well-drained, medium-textured soils; a strong, light-demanding species.

Plant Characteristics:

To 30 m; deciduous; light canopy (coffee, cacao intercropped in Costa Rica; see Figure 8.6); large superficial, spreading roots (deep when soil conditions are favorable); wind-resistant and shade-intolerant; propagated by direct seeding, seedlings, and root suckers; coppices.

Main Uses:

Timber; poles; shade tree for crops (cacao, coffee); soil improvement; fuelwood (sp. gr. 0.29–0.70); food (fruits); ornamental.

Comments:

A renowned timber species; permits understory crops; attacked by canker-causing rust disease on poor sites; low seed viability (1–2 months only); silviculture well developed; wood is resistant to decay and termites.

• Dacryodes edulis (G. Don.) H. J. Lam.

• (Burseraceae)

Synonyms:

Canarium edule (G.Don) Hook.f., C. mansfeldianum Engl., Pachylobus edulis G. Don., P. saphu (Engl.) Engl.

Origin and Distribution:

Africa; introduced to Malaysia

Ecology:

Occurs in the evergreen rainforest, gallery forest and marshes; adapts well to differences in day length, temperature, rainfall, and soils; prefers altitude up to 1000 m, mean annual precipitation of 1400–4000 mm, and mean annual temperature of 23–25 °C.

Plant Characteristics:

A medium-sized, evergreen tree, 18–40 m tall in the forest but about 12 m in plantations; deep, dense crown; short bole; 50–170 cm in diameter; shade-loving.

Main Uses:

Pulpy, pericarp eaten either raw or cooked; fruit pulp rich in vitamins and contains a range of amino acids, yields about 48% edible oil; kernel fed to sheep and goats (about 3.3% protein); wood for making tool handles, suitable for carpentry; bark and leaves medicinally important; suited for intercropping.

Comments:

Known as African pear and African plum; planted in southern Nigeria, Cameroon, and the Democratic Republic of Congo for its nutritious fruit.

• Dalbergia sissoo Roxb. ex DC

• (Fabaceae; Papilionoideae)

Origin and Distribution:

Native to the Himalayan foothills (India, Pakistan, and Nepal); introduced to the USA and the western and eastern parts of Africa.

Ecology:

Occurs in the subtropics to tropics on semiarid sites and neutral to acid soils with good drainage; altitude up to 1500 m; mean annual temperature –4 to 45 °C; rainfall 500–4500 mm.

Plant Characteristics:

A medium to large-sized deciduous tree, up to 30 m height and 80 cm diameter at breast height (under favorable conditions); wide-spreading and thin crown; N₂ fixing; light-demanding; coppices; fast-growing; frost-resistant and drought hardy; propagated by direct seeding, seedlings, stump sprouts, root suckers, and branch cuttings.

Main Uses:

Fuelwood (sp. gr. 0.83, 5–8 m³ ha^–1 yr^-1; calorific value 4.9–5.2 kcal g^–1); sawn timber; fodder; soil erosion control; ornamental; heartwood very hard and close-grained; used for high-quality furniture, cabinets, decorative veneer, carving, engraving, tool handles and sporting goods; heartwood yields light brown, viscous, non-drying fixed oil (5.35%), suitable as a lubricant for heavy machinery; planted in homegardens; medicinally important.

Comments:

Termites attack young plants; seedlings do not compete well with weeds (weeding for 2-3 years required); browsed heavily by wild animals.

• Erythrina poeppigiana (Walp.) Cook

• (Fabaceae; Papilionoideae)

Synonyms:

Erythrina micropteryx Poeppig ex Walpers, Micropteryx poeppigiana Walpers.

Origin and Distribution:

Latin America from Costa Rica to Bolivia; introduced to West Indies.

Ecology:

Native to the riverine and upland forests of the Amazon and Orinoco Basins. Cultivated and naturalized trees are found at elevations up to 2000 m in dry to subhumid tropics (1500–4000 mm annual rainfall, up to 6-month dry seasons) at medium altitudes to highlands.

Plant Characteristics:

To 40 m; fast growth; N₂ fixing (abundantly nodulated with Bradyrhizobium); coppices; propagated by direct seeding, seedlings, and cuttings; can tolerate drought and temporary waterlogging; but cannot grow under shade.

Main Uses:

Shade tree for coffee (See Figure 8.4) and cacao; support plant for betel, black pepper, vanilla, and grape vines; live fences (cuttings easily root); ornamental; soil fertility improvement; fodder; green manure (8–12 Mg ha^-1 yr^-1 produced); alley cropping; live fencing.

Comments:

One of the most commonly planted shade trees for cacao and coffee, and support for black pepper in Central America; increases soil fertility; good coppicing ability.

Related Species (used commonly in agroforestry systems):

E. berteroana in Central America, and E. indica in India.

• Euterpe oleracea [The Açaí (Assai) palm]

• (Arecaceae)

Synonym:

Erythrina micropteryx Poeppig ex Walpers, Micropteryx poeppigiana Walpers.

Origin and Distribution:

Brazil and the northern parts of South America.

Ecology:

Native to Brazil, Ecuador, Venezuela, Colombia, Guyana, mainly in swamps and floodplains.

Plant Characteristics (Figure 13.A.I.13):

A tall, slender palm growing to more than 25 m. To 40 m; seed-propagated; bears fruit all around the year; usually two harvests per year, one between January and June and the other between August and December

Figure 13.A.I.13

Euterpe oleracea [The Açaí (Assai) palm) in Belém, Pa, Brazil]. (Photo: Charles Clement)

Main Uses:

Cultivated for its fruit (açaí berries), hearts of palm (a vegetable), leaves, and trunk wood. With the extension of consumption of the (small, round, and black-purple) fruit from the floodplain areas to urban centers and its promotion as a health food since the 1990s, its global demand has expanded rapidly.

Comments:

Popular as a fruit, fruit supplement; the “açaí bowl” a combination of frozen açaí puree or açaí powder with other ingredients such as nut milk, fruit juice, fruit, nuts, oatmeal, and a sweetener has become a popular dessert in North America.

• Faidherbia albida Del. A. Chev.

• (Fabaceae; Mimosoideae)

Synonym:

Acacia albida Del., Acacia albida var. senegalensis Benth., Acacia gyrocarpa Hochst. ex A. Rich., Acacia mossambicensis Bolle, Acacia saccharata Benth.,

Origin and Distribution:

Widespread in dry tropical Africa into the Middle East and Arabia. Introduced into India, Pakistan, Nepal and, in the Western Hemisphere, Peru.

Ecology:

Found in arid and semiarid regions (400–900 mm annual rainfall) at altitudes of 100–2500 m on variable soils, but loamy and sandy types preferred.

Plant Characteristics (See Figures 9.7–9.10):

To 20 m with wide, spreading crown; leaves shed during rainy season and retained during the dry season (West Africa). Propagated by direct seeding (after scarification), seedlings, root suckers; coppices well; N₂ fixing.

Main Uses:

Forage (pods, foliage); shade; fencing (cut thorny branches); tannin; medicine.

Comments:

Slow early growth; considerable stand variability; soil fertility improvement with 5–76% increases in crop yields under trees reported. The remarkable phenological characteristic of the trees shedding their leaves in the rainy season and the leaves reappearing at the beginning of the dry season is acclaimed as the “Albida Effect” in agroforestry literature. This special feature, however, is not conspicuously expressed on trees growing outside the West African Sahel.

• Flemingia macrophylla (Willd.) Merr.

• (Fabaceae; Papilionoideae)

Synonyms:

F. congesta Roxb. ex Ait.f.; 26 other Latin names.

Origin and Distribution:

Native to South and Southeast Asia; introduced to parts of Africa and tropical America; has long been used – and thus become naturalized – throughout the East-, Central-, and West Africa, Hawaii and North Australia for soil improvement.

Ecology:

Found in the sub-humid and humid tropics at low to medium altitudes on sites with 1000–2000 mm annual rainfall (including up to 4 month dry seasons) on a wide range of soils; capable of surviving on poorly drained soils with waterlogging.

Plant Characteristics:

Woody, tussock-forming shrub, erect or prostrate, 3 – 4 m tall, with a spreading crown; fast growing; deep-rooted; N₂ fixing; tolerant of light shade; coppicing ability; propagated by direct seeding or seedlings.

Main Uses:

Fodder; support for climbing plants; soil erosion control (in contour hedgerows); green manure; cover crop; dye; traditional medicine; used for agroforestry in Nepal and Bhutan.

Comments:

After becoming established (3–4 months), the plant can out-compete many weeds; weeding during the first 2 months necessary. Large-scale plantations have been established in south China and India for lac insect (Kerria lacca) breeding; potentially invasive.

• Gliricidia sepium (Jacq.) Walp.

• (Fabaceae; Papilionoideae)

Synonyms:

Galedupa pungam Blanco, Gliricidia lambii Fernald, G. maculata (Kunth) Walp., Robinia maculata Kunth, R. sepium Jacq., R. variegata Schltdl, and a few others.

Origin and Distribution:

Native to Mexico and Central America; extensively introduced to West Indies, Africa, Southeast and South Asia and the Pacific islands.

Ecology:

Grows in dry to humid tropics (600–3000 mm annual rainfall) at 500–1600 m on moist to dry, and even saline soils; tolerates brief waterlogging.

Plant Characteristics:

To 10 m; medium-sized tree; fast growth; N₂ fixing; coppices; easily propagated by direct seeding, seedlings, and cuttings.

Main Uses:

Shade for cacao, coffee, vanilla, and tea; green manure; fodder (mainly for cattle); honey production; live fences; ornamental; alley cropping; medicinal (leaves); grown in hedges; on terraces to control soil erosion; soil fertility improvement; wood is often utilized as firewood and for charcoal making (density: 47–75 g cm^–3; calorific value: 4900 kcal kg^–1).

Comments:

One of the most widely planted agroforestry species (Figures 6.1, 6.2, 11.10). Popular as a shade tree for cacao in Central America and known as the Madre de cacao (Spanish for Mother of cacao); “Quick stick” in the Caribbean islands, where one-year old shoots planted along with yams establish roots fast and sprout vigorously to and provide support for trailing the yam shoots.

• Grevillea robusta A. Cunn. ex R. Br.

• (Proteaceae)

Synonyms:

G. robusta var. compacta auct., G. robusta var. forsteri L.H.Bailey,

Origin and Distribution:

Native to Australia; introduced to the warm temperate, subtropical and tropical highland regions around the world; widely planted in South Asia, Central and South America and many countries in Africa.

Ecology:

Found in humid to subhumid climates (400–1500 m annual rainfall with up to 6–8month dry seasons) from sea level to 2300 m on a wide range of soils, but deep soils preferred.

Plant Characteristics:

Erect, single-stemmed tree reaching 20–30 m tall and 80 cm in stem diameter; crown is conical and symmetrical; fast growth; deep-rooted; pollards well but does not coppice well; propagated by direct seeding or seedlings.

Main Uses:

Shade tree for coffee and tea (See Figures 8.7, 8.19); fuelwood (sp. gr. 0.57, 217 m³ ha^-1 from 14-year-old plantation); mulch; ornamental; honey production; soil improver; sawn timber of medium strength for furniture, packing cases, flooring, paneling; poles for house-construction, scaffolding; firewood and charcoal; calorific value of heartwood 4950 kcal kg^–1.

Comments:

Low seed viability unless refrigrated; can become a weed due to vigorous natural regeneration from seed; does not tolerate waterlogging.

• Grewia optiva J.R. Drumm. ex Burret

• (Tiliaceae)

Synonyms:

Grewia oppositifolia Buch.-Ham. ex Roxb.

Origin and Distribution:

Native to Indian sub-continent.

Ecology:

Tree of the subtropical climate found in highland subhumid regions with bimodal, monsoonal rainfall (1700–2200 mm annually); altitude up to 2000 m; medium, loamy to heavy, clayey, well-drained soils with a neutral to alkaline pH.

Plant Characteristics:

Erect, straight habit; single to multi-stemmed with a dense canopy; deep rooting; height ranges from 7–10 m; regenerated by seedlings, coppice from stumps, and direct seeding.

Main Uses:

Edible pods and fruits; fodder; furniture; wood for construction; fiber; charcoal; often planted in hedges and field boundaries; suitable for intercropping.

Comments:

Light-demanding; drought sensitive; intolerant of fire and strongly acidic soils; susceptible to browsing damage; moderately frost resistant; tolerates strongly alkaline soils; can withstand heavy lopping or pollarding.

• Inga edulis Mart.

• (Fabaceae; Mimosoideae)

Synonyms:

Feuilleea edulis (Mart.) Kuntze and seven other names

Origin and Distribution:

Native to tropical South America.

Ecology:

Generally associated with warm, lowland, wet tropics; remarkably resistant to drought and cold; to1600 m altitude; mean annual rainfall 1200 mm; tolerant to acid and poor soils.

Plant Characteristics:

Evergreen fast-growing tree; to 25 m tall; light-demanding; nitrogen fixing; propagation by seeds; seeds are recalcitrant and sometimes begin to germinate in the pod.

Main Uses:

Food; fodder (pigs eat seeds when hungry, and cattle will even eat whole pods and leaves); timber; firewood (high calorific value and little smoke); shade tree for perennial crops (mainly coffee and cacao); soil improver; controls soil erosion.

Comments:

Commonly known as ice cream bean tree; useful for the smallholder’s woodlot and a useful bush-fallow species.

Related Species

common in agroforestry systems in Central and South America

• Inga jinicuil G. Don

• Inga vera Willd. ssp. vera

• Juglans nigra L. (Black Walnut)

• (Juglandaceae)

Synonyms:

Wallia nigra (L.) Alef.

Origin and Distribution:

Native range is Eastern United States but widely planted outside of its natural range and can be found all over North America.

Ecology:

Prefers moist, organically rich, well-drained soils; occurs in association with other hardwoods; grows best in areas with an annual precipitation from 300 to 1300 mm, an annual temperature in the range of 7 to 19 °C and soils of pH from 4.9 to 8.2.

Plant Characteristics (See Figures 10.1, 10.15):

Large deciduous tree; to 30 m tall; fast growth; propagated through seeds or through grafts; shade intolerant; not frost tender; well adapted to fire.

Main Uses:

Most popular wood used for fabricating solid and veneer furniture; wood very ornamental, heavy, hard, strong, close-grained, durable; seed eaten raw or cooked; high nutritional value; used in several dishes; an excellent dessert nut; seed yields an edible oil; the tree yields a sweet sap that can be drunk or concentrated into syrup or sugar; bark and leaves medicinally important; suitable for interplanting or multicropping.

Comments:

Long recognized as one of the most valuable North American trees; produces a toxin called juglone with allelopathic effects. Several walnut hybrids (e.g., Juglans nigra x J. regia and J. major x J. regia) have been planted into existing woodlands in Europe.

• Juglans regia L. (English or Persian Walnut)

• (Juglandaceae)

Synonyms:

J. duclouxiana Dode, J. orientis Dode, J. sinensis (C. DC.) Dode

Origin and Distribution:

Originated in the region from Eastern Balkans to the Himalayas; cultivated in the temperate regions; sometimes hybridized with black walnut (J. nigra).

Ecology:

Requires moist, organically rich, well-drained soils with pH values between 6 and 7.5; intolerant to shade; sensitive to competition.

Plant Characteristics:

Large, long-living deciduous tree; height up to 45 m; light-demanding; propagated by seeds or vegetatively through cuttings, grafting, or layering.

Main Uses:

Highly valued for its nutritional seeds (walnuts) and timber; the kernel is consumed, fresh or toasted, alone or mixed with other products; fruits yield oil rich in polyunsaturated fatty acids, tocopherols, and phytosterols, used in paints and in soap-making; high-quality timber used for making furniture and veneer; bark and leaves have medicinal values; tannins extracted; leaves contain juglone with pesticidal and herbicidal properties.

Comments:

Fruits, leaves, and alcoholic products from green fruits have antioxidant potential.

• Khaya ivorensis A. Chev. (African mahogany)

• (Meliaceae)

Synonyms:

K. caudata Stapf ex Hutch. & Dalziel; K. klainei Pierre ex Pellegr.

Origin and Distribution:

Native range from coastal West Africa, Cote d’Ivoire through Ghana and southern Nigeria to Cameroon; introduced to Fiji, Indonesia, Malaysia.

Ecology:

A plant of moist tropical lowland areas; mostly in rainforest; altitude up to 450 m; mean annual temperature 24–27 °C and rainfall 1600–2500 mm; prefers wet alluvial soils.

Plant Characteristics:

Very large evergreen tree, deciduous in drier climates; 40–50 m tall and up to 2 m dbh (diameter at breast height); straight, unbranched bole up to 30 m; well-developed plank buttresses; grows very quickly; mainly seed propagated; also by cuttings; light-demanding.

Main Uses:

Wood is durable (mean specific gravity 0.53 g m^–3) and of high market value; used for high-quality cabinetwork, furniture, and expensive interior finishing; bitter bark is medicinal; soil improver.

Comments:

Planted as mixed species stands with close spacing; sole stands are rarely established because of insect damage; “vulnerable”’ as per the IUCN Red list.

Related Species

Khaya senegalensis (Desr.) A.Juss. Moist African tropics (Senegal to Uganda), medium-sized, popular, hard timber; leaves relished by cattle and camels; vulnerable as per IUCN Red List.

• Leucaena leucocephala (Lam.) De Wit

• (Fabaceae; Mimosoideae)

Origin and Distribution:

Native to Central America and Mexico; introduced to much of South and Southeast Asia, Africa, South America, and the Caribbean.

Ecology:

Occurs in lowland dry to humid tropics (below 500 m, 600–1700 mm annual rainfall) on neutral to alkaline soils but not waterlogged sites; sea level to 1800 m altitude.

Plant Characteristics:

To 18 m (shrubby and arboreal varieties known); N₂ fixing; deep-rooted; coppices very well; prolific seeder and seeds germinate rapidly; propagated by direct seeding, seedlings; fast-growing.

Main Uses:

Fuelwood (sp. gr. 0.55, 24–100 m³ ha^-1 yr^-1); nurse tree; fodder; small construction wood and pulpwood; some food use (pods, seeds, leaves); energy plantations; alley cropping.

Comments:

Possibly the most studied and mentioned species in tropical agroforestry. The fodder is relished by cattle (Figure 13.A.I.14; See also Figures 6.3, 6.7, 18.10), but the leaves contain an alkaloid (mimosine) which may be mildly toxic to cattle if fed on it a sole diet for long periods; usually mixed with grasses to alleviate the problem.

Figure 13.A.I.14

Cattle browsing the new shoots of Leucaena leucocephala in the height of the dry season when fodder scarcity is at its peak, in Queensland, Australia. (Photo: Vimala Nair)

Related Species

Leucaean diversifolia, another species used in agroforestry systems, though to a less extent, is adapted to tropical highlands; has been used in breeding programs with L. leucocephala.

• Madhuca longifolia (Roxb.) A.Chev.

• (Sapotaceae)

Synonyms:

M. indica J.F. Gmel., M. latifolia (Roxb.) J.F. Macbr. (and a few other names)

Origin and Distribution:

Indigenous to India, Sri Lanka, Nepal, Myanmar.

Ecology:

A plant of the subtropics to the hot tropics; elevations up to 1200 m; mean annual rainfall 550–1500 mm; temperature 2–46 °C; common in deciduous forests and dry sal (Shorea robusta) forests; prefers deep loamy or sandy-loam soil with good drainage.

Plant Characteristics:

A deciduous tree about 15 m tall; large, spreading, rounded crown; drought resistant; propagated by direct seeding, frost resistant; requires full light.

Main Uses:

Edible flowers, fruits, leaves and oil; the fragrant fleshy flowers are eaten raw or cooked; flowers are also used to brew an alcoholic beverage; seed yields a low-quality oil used in making of soap and candles; bark yields tannin; seed oil are medicinally important; durable and heavy wood (929 kg m^–3) used for house construction, furniture and as a fuel; soil improver; soil reclamation and erosion control.

Comments:

Commonly known as Mahua or butter tree; cultivated or harvested in the wild in Southern Asia.

• Melia azedarach L.

• (Meliaceae)

Origin and Distribution:

Native to Indian sub-continent; introduced to the Middle East, West Indies, southern U.S., Mexico, Argentina, Brazil, and parts of West and East Africa and Southeast Asia.

Ecology:

Occurs in low to midlands (up to 2000 m) on sites with 600–1000 mm of annual rainfall on variable soils.

Plant Characteristics (Figure 13.A.I.15):

To 30 m; fast growth; short-lived (20–30 years); coppices; shade-intolerant; propagated by root suckers, direct seeding, and seedlings; generally deciduous, but evergreen in the humid tropics.

Figure 13.A.I.15

Melia azedarach. (Photo: BM Kumar)

Main Uses:

Fuelwood (sp. gr. 0.66); wood for furniture, plywood, and boxes; insecticide and repellent (leaves, dried fruit); fodder (leaves for goats); ornamental; a wide range of medicinal applications; widely planted as a shade tree in coffee and abaca (Musa textilis) plantations.

Comments:

Known as Persian lilac; susceptible to wind damage; drought-tolerant; bruised bark and leaves as a fish poison.

• Mimosa scabrella Benth.

• (Fabaceae; Mimosoideae)

Synonyms:

M. bracaatinga Hoehne,

Origin and Distribution:

Native to South and southeastern Brazil, Northeast Argentina; introduced into Central America and East Africa.

Ecology:

Grows at mid-elevations in the cool tropical and subtropical regions (prefers annual rainfall > 1000 mm) on a wide range of well-drained soils; tolerates strongly acid soils with high aluminum content; does not tolerate waterlogging.

Plant Characteristics:

To 12 m; thornless; slender; fast-growing; shrubby varieties also exist; N₂ fixing; coppices; propagated by direct seeding, seedlings.

Main Uses:

Fuelwood; pulpwood; ornamental; green manure; shade for coffee; soil improver; live fence; heartwood is hard, moderately heavy, specific gravity from 450 to 670 kg m^–3, used for lumber.

Comments:

Flourishes at 2400 m in Guatemala; before the advent of the diesel locomotive, M. scabrella wood was grown to fuel railroads in parts of Brazil.

.

• Moringa oleifera Lam.

• (Moringaceae)

Synonyms:

Guilandina moringa L., Hyperanthera moringa (L.) Vahl, M. moringa (L.) Millsp., M. pterygosperma Gaertn., M. zeylanica Burmann

Origin and Distribution:

Native to India and Arabia; now pantropical.

Ecology:

Occurs in the lowland tropics (0–750 m, 760–2250 mm annual rainfall) on well-drained, deep soils (pH 5–7 preferred).

Plant Characteristics (Figure 13.A.I.16):

To 12 m; fast growth; open crown; coppices; propagated by direct seeding, cuttings.

Figure 13.A.I.16

Moringa oleifera in Taiwan. (Photo: Manny Palada)

Main Uses:

Food (pods when young, leaves, roots, flowers); fodder (leaves); honey production; medicine (bark, roots, leaves); water purification (seeds); soap (seeds); industrial lubricant.

Comments:

Competes well with weeds (allelopathic effects suggested); waterlogging not tolerated. Popular in agroforestry (homegarden) systems.

• Paraserianthes falcataria (L.) Nielson

• (Fabaceae; Mimosoideae)

Synonym:

Albizia falcataria (L.) Fosberg., Falcataria moluccana (Miq.) Barneby & J.W.Grimes.

Origin and Distribution:

Native to South and Southeast Asia, and the Pacific islands.

Ecology:

Found in moist tropics without dry seasons (1000–4500 mm annual rainfall) at 800–1500 m on well-drained soils; a pioneer species, sensitive to fire.

Plant Characteristics:

To 45 m; umbrella-shaped crown when grown in the open; fast growth (15 m in 3 years); propagated by seeds (after scarification) and seedlings; N₂ fixing; coppices.

Main Uses:

Pulpwood (soft wood with 0.33 sp. gr.); moldings; boxes; soil improvement; fuelwood (but quality is poor).

Comments:

Subject to wind damage; can aggravate soil erosion; yields 39–50 m³ ha^-1 yr^-1 of wood on a 10-year rotation cycle; competes well with weeds.

• Parkia biglobosa (Jacq.) R. Br. ex G. Don f.

• (Fabaceae; Mimosoideae)

Origin and Distribution:

Native to West Africa; widespread in the Caribbean.

Ecology:

Occurs in semiarid to subhumid lowlands (0–300 m; 400–1500 mm annual rainfall) on acid soils; prefers well-drained, deep soils, but also found on shallow soils, and thick laterites.

Plant Characteristics (Figure 13.A.I.17):

To 20 m; deciduous; dense, spreading crown; N₂ fixing; coppices; propagated by direct seeding, seedlings.

Figure 13.A.I.17

Parkia biglobosa with crops underneath, in Mali. (Photo: PKR Nair)

Main Uses:

Timber (sp. gr.: 0.58–0.64); fuelwood; condiment (crushed, fermented pods); fodder (pods, but high tannin); fish poison (fruit husks and bark); medicinal; shade.

Comments:

Drought-tolerant (3–7 months dry season) because of its deep taproot system and an ability to restrict transpiration.

• Parkinsonia aculeata L. (Fabaceae; Caesalpinoideae)

Synonym:

P. thornberi M.E.Jones

Origin and Distribution:

Native to southwestern U.S., through Mexico and Central America to South America; introduced to Hawaii, South Africa, East Africa, India, Jamaica, and Israel.

Ecology:

Grows in widely disparate climates, from dry to humid tropics (200–1000 mm annual rainfall) and in the subtropics at altitudes below 1300 m on various soils; tolerant to drought, waterlogging and salinity.

Plant Characteristics:

A small, spiny tree 4–10 m high, with a short and often crooked trunk up to 40 cm in diameter; spreading habit; fast growth; coppices; propagated by root suckers, cuttings, direct seeding, and seedlings.

Main Uses:

Fuelwood; fodder (leaves, pods); food (pods); ornamental; apiculture; medicinal (leaf, fruit and stem); erosion control; live fences.

Comments:

Not an N₂ fixer; seedlings respond to fertilizers; young plants may be damaged by termites; intolerant of waterlogged soils; a prohibited weed in Australia and a serious pest in many other countries.

• Pongamia pinnata (L.) Pierre

• (Fabaceae; Papilionoideae)

Synonym:

Derris indica (Lam.) Bennet. and 16 other names.

Origin and Distribution:

Native to South and Southeast Asia; introduced to the Philippines, Australia, and subtropical U.S.

Ecology:

In mesic tropics (0–1000 m, 500–2500 mm annual rainfall) on sandy and rocky soils.

Plant Characteristics:

Deciduous, glabrous shrub or tree, 15–25 m high; aggressive, spreading roots; propagated by direct seeding, seedlings, cuttings, and root suckers; nitrogen fixing.

Main Uses:

Fuelwood (calorific value of 4600 kcal kg^–1); fodder; oil (seeds); pest control (leaves); shade; medicine (leaves, flowers, bark, and sap); bark fiber for rope; apiculture; ornamental; soil improver; erosion control; press-cake is a pesticide, particularly against nematodes.

Comments:

Tolerates saline soils; grows to full height in 5 years; spread through root suckers can become a weed; not a quality timber; host for the lac insect and for the hemiparasitic sandalwood, Santalum album (India); promising biofuel crop; dried leaves are stored with grain to repel storage pests; pounded and roasted seeds used as fish poison.

• Populus deltoides Bartr. ex Marsh. (Poplar, Cottonwood)

• (Salicaceae)

Origin and Distribution:

Native to USA and Canada; introduced to Australia, China, India, Nepal, Netherlands, New Zealand, Pakistan, Sweden, United Kingdom.

Ecology:

A wide range of habitats; prefers moist, well-drained, fine, sandy loams or silts, pH of 4.5–8; altitude up to 1000 m; mean annual temperature 8–14 °C; rainfall 600–1500 mm.

Plant Characteristics:

Medium-sized to large tree, 20–30 m tall, 100 cm diameter at breast height; fast growth; propagation by cuttings; natural regeneration by seed; tolerates frost, heavy soil and waterlogging; intolerant to competition.

Main Uses:

Timber (lumber, veneer, pulpwood and excelsior); fuelwood; fodder; tannin/dyestuff; medicine (bark, fresh flowers, leaves root); shade or shelter; soil improver; boundary planting; ornamental; windbreak; component of agroforestry.

Comments:

Annual productivity 3 to 22 t ha^–1; widely used in the USA and Canada for amenity plantings; poplar-based agroforestry (poplar+wheat) popular in India (See Figures 12.5-12.7); hybrid poplars (e.g., Populus deltoides x Populus nigra; Populus alba × Populus tremula; Populus deltoides x Populus trichocarpa) exhibit very fast-growth rates; many clones available.

• Prosopis cineraria (L.) Druce (The Khejri tree)

• (Fabaceae; Mimosoideae)

Synonyms:

Adenanthera aculeata Roxb., Mimosa cineraria L., P. spicata Burm

Origin and Distribution:

Native to India; introduced to West Asia and the Middle East.

Ecology:

Occurs in dry lowland tropics (75–850 mm rainfall, 6–8 months dry period) on well-drained, light to heavy soils.

Plant Characteristics

(See Figures 9.2, 9.16): Up to about 9 m tall with a spreading habit; thorny; N₂ fixing; deep-rooted; coppices; propagated by root suckers, seeds, and seedlings; light-demander.

Main Uses:

Fuelwood and charcoal (2.9 m³ ha^-1 yr^-1); fodder; wood for posts, tool handles; green manure; afforestation; dried and green pods used as vegetable in many parts of the Thar desert in India; medicinal; gums/resins; tannins; soil improver; intercropping.

Comments:

May become a weed in sub-humid environments; some populations display high genetic variability; tolerates saline soils, high alkalinity (pH 9.8), and seasonal waterlogging; suited for sand dune stabilization and reclamation.

Other major species of Prosopis in Agroforestry Systems

(all adapted to dry regions; their taxonomy is not clear)

• Prosopis chilensis (Molina) Stuntz: (The Mesquite Tree) Native to Argentina, Chile, Peru; introduced to Africa, Asia, and the USA.

• Prosopis juliflora (Sw.) DC., syn. Acacia juliflora: Native to southwestern U.S., Central America; introduced to many arid zones of the world (e.g., Africa, and Asia).

• Prosopis pallida (Humb. et Bonpl. ex Willd.) Kunth: dry parts of Peru, Colombia, and Ecuador.

• Robinia pseudoacacia L.

• (Fabaceae; Papilionoideae)

Synonyms:

R. pringlei Rose

Origin and Distribution:

Native to northeastern U.S.; introduced to European temperate and Mediterranean regions, as well as India, and Thailand.

Ecology:

Grows in temperate and highland tropical regions (1500–2500 m, 300–1000 mm annual rainfall) on variable soils; does well on calcareous, well-drained loams.

Plant Characteristics:

To 25 m; fast growth; deciduous; thorns on young branches; N₂ fixing; shallow root system; coppices; propagated by root suckers, direct seeding, seedlings, cuttings, and stump sprouts; drought-hardy (2–6 months); cold tolerant, does not tolerate waterlogging.

Main Uses:

Fuelwood (sp. gr. 0.68, 4–10 m³ ha^-1 yr^-1); erosion control; nurse tree; timber; posts; fodder (high tannins in young leaves, and lectin proteins can interfere with livestock digestion); windbreak; ornamental; honey production; soil improver; mine-land reclamation.

Comments:

Aggressive colonizer; tolerates slightly saline soils; grows well on poor sites as acidic as pH 4.8; pioneers on disturbed soils or burned sites; dominates early forest regeneration in many native forests; can be lopped annually.

• Samanea saman (Jacq.) Merr. (The Rain Tree)

• (Fabaceae; Mimosoideae)

Synonyms:

Albizia saman (Jacq.) F. Muell; Pithecellobium saman (Jacq.) Benth.

Origin and Distribution:

Native to northern South America; now widely naturalized.

Ecology:

Occurs in sub-humid to wet lowland tropics with less than 6-months dry season; a wide adaptability up to 1000 m altitude in both monsoonal and equatorial climates with an annual rainfall of 1000–2500 mm; tolerates seasonal dry periods (2–4 months).

Plant Characteristics (Figure 13.A.I.18):

To 40 m with a wide, spreading crown; fast growth; N₂ fixing; coppices; light-demander; propagated by direct seeding, seedlings, and cuttings.

Figure 13.A.I.18

Samanea saman: Animals seeking shelter from the hot sun under the tree. (Photo: ICRAF/World Agroforestry)

Main Uses:

Fuelwood (calorific value: 5200–5600 kcal kg^–1); food (pods); fodder (pods, leaves); timber; wood for crafts; shade (coffee, cacao); green manure; ornamental.

Comments:

A valuable source of high-quality firewood and charcoal; but a strong market for woodcarvings makes the wood too valuable to be used as fuel; the tree, because of its large crown, is not good for croplands but is used in grazing lands.

• Senna siamea (Lamarck) Irwin et Barneby

• (Fabaceae; Caesalpinioideae)

Synonyms:

Cassia siamea Lam., C. sumatrana Roxb., and several other names

Origin and Distribution:

Native range is Asia; introduced to Africa, Americas and Oceania.

Ecology:

Grows under a wide range of climatic conditions (humid through to arid), tolerates low (500 mm) and high rainfall (2800 mm); but cannot tolerate low temperatures (<10 °C); no exacting soil requirements; but prefers moist soils with good drainage; sensitive to poor drainage; soil pH 5.5–7.5.

Plant Characteristics:

Medium-sized tree (10 to 12 m height); dense, round, evergreen crown; coppices; not an N₂ fixer; frost sensitive; endures dry period (4 to 6 months); fast growth.

Main Uses:

Good quality durable timber; resistant to termites; often used for walking sticks, boxes, axe handles; erosion control; alley cropping (See Figures 6.5, 18.13); shelterbelts and windbreaks; afforestation in the dry zones of India; for reclamation of abandoned tin-mined areas in Nigeria; intercropping; shade tree for coffee, cocoa and tea, nurse crop for Swietenia mahogani to reduce borer attack, and a host for the hemi-parasite sandalwood; widely grown for fodder.

Comments:

Invasive outside its native range; fodder for cattle, sheep, and goats but problems with alkaloids and other secondary plant compounds in the leaves, flowers and pods.

• Sesbania grandiflora (L.) Pers.

• (Fabaceae; Papilionoideae)

Synonyms:

Agati grandiflora (L.) Desv., Robinia grandiflora L, and a few other names.

Origin and Distribution:

Native to South and Southeast Asia; introduced to the Caribbean, Central and South America, Australia, and parts of Africa.

Ecology:

Occurs in the moist lowland tropics (1000 mm annual rainfall, 0–800 m altitude); well-adapted to hot, humid environments; tolerates periodic flooding and a variety of soil conditions.

Plant Characteristics:

Small, loosely branching tree, 8–15 m tall; fast growth; N₂ fixing; coppices but not vigorously; propagated by direct seeding, seedlings, and cuttings.

Main Uses:

Fuelwood (sp. gr. 0.42, 4278 kcal kg^–1, 20–25 m³ ha^-1 yr^-1); fodder (pods, leaves); food (young leaves, pods, flowers); green manure; pulpwood; medicinal uses (leaves, bark); soil improver; living fence; live support for crops such as vanilla and pepper.

Comments:

Complementary to many agricultural systems (Figure 13.A.I.19); harvested over short rotations (3 year); susceptible to beetle attacks; short-lived; does not tolerate repeated pruning.

Figure 13.A.I.19

Sesbania grandiflora on the bunds (risers) between plots of rice paddies in Java, Indonesia. (Photo: PKR Nair)

• Sesbania sesban (L.) Merr.

• (Fabaceae; Papilionoideae)

Synonyms:

Aeschynomene sesban L. and 14 other names.

Origin and Distribution:

Native to East Africa; widely introduced in tropical Africa and Asia.

Ecology:

Native to subhumid tropics (300–1200 m, 350–1000 mm annual rainfall) on variable soils. In its native range, the plant grows along streams, swamp edges, moist and inundated bottomlands; tolerant to moisture stress and saline and alkaline soils.

Plant Characteristics (Figure 13.A.I.20):

Deciduous, short-lived perennial shrub or tree, 1–7 m tall; narrow-crowned; deep-rooted; single- or multi-stemmed; fast growing; N₂ fixing; coppices; propagated by direct seeding and seedlings; moderately shade tolerant.

Figure 13.A.I.20

Sesbania sesban, fast-growing green manure/fallow species for soil fertility improvement in the humid tropics. (Photo: ICRAF/World Agroforestry)

Main Uses:

Fuelwood and charcoal (calorific yield: 4350 kcal/kg); food (leaves and flowers); fodder (leaves and young branches); green manure; erosion control; windbreak for bananas, citrus, and coffee; soil improver; promising shrub for alley cropping and fallow improvement.

Comments:

Open crown and slender habit permits understory crops; 30 t ha^-1 yr^-1 fuelwood yield; soft wood; rhizobium strains specific to host genotype required; invasive outside its native range.

• Syzygium aromaticum (L.) Merr. & Perr. (The Clove Tree)

• (Myrtaceae)

Synonyms:

Eugenia aromatica (L.) Baill., E. caryophyllata Thunb., E. caryophyllus (Spring)

Origin and Distribution:

Native to Indonesia; exotic range includes Brazil, Haiti, India, Kenya, Madagascar, Malaysia, Mauritius, Mexico, Seychelles, Sri Lanka, Tanzania.

Ecology:

Tropical evergreen tree; occurs in woodland and rainforests up to 1000 m elevation; 1500–2500 mm mean annual rainfall; prefers loamy humus-rich soils.

Plant Characteristics (Figure 8.16):

Small to medium sized, multi-stemmed tree, 8–30 m tall; seed propagated (require a pretreatment of soaking in water for three days); softwood grafting.

Main Uses:

The unopened flower bud on the terminal shoots is the clove of commerce – an important spice; leaves, flowers and bark are aromatic; yields an essential oil; medicinal use.

Comments:

Clove trees need light shade; interplanted with coconut palms; live for more than 100 years; Sumatra disease caused by Pseudomonas solancearum, a bacterium, causes dieback and mass decline.

Related Species:

• Syzygium cuminii (L.) Skeels; Synonyms: Eugenia cumini (Linn.) Druce., Syzygium jambolana DC., and others. Native to India, Sri Lanka, and Myanmar; introduced into many other tropical and subtropical countries in Asia, Africa, Americas and Oceania.

• Syzygium malaccense (L.) Merr. & L. M. Perry (Malay Apple): Southeast Asia and Polynesia.

• Tamarindus indica L.

• (Fabaceae; Caesalpinoideae)

Origin and Distribution:

Native to semiarid tropical Africa; introduced to the Caribbean, Latin America, India, and Australia.

Ecology:

Grows in lowland dry and monsoonal tropics (400–1500 mm annual rainfall) on well-drained, deep soils (pH 5.5); up to 2000 m altitude.

Plant Characteristics (Figure 13.A.I.21):

To 30 m tall with a wide crown; evergreen; deep tap root; propagated by direct seeding (after hard seed coat is nicked), seedlings, or cuttings; coppices.

Figure 13.A.I.21

Tamarindus indica – a popular tree on farmlands and countrysides throughout Africa and South- and Southeast Asia. (Photo: BM Kumar)

Main Uses:

Food and seasoning (pod juice and pulp, leaves, and flowers); fodder (leaves and seeds); fuelwood and charcoal (sp. gr. 0.93; calorific value of 4850 kcal kg^–1); timber; firebreak; ornamental; shade; medicine (fruit, leaves, flower, bark); tannin (ash and bark); live fences.

Comments:

Early growth is slow; fruits ripen well only in areas with extended dry seasons; production starts at 8–12 years and continues for up to 200 years; normally found associated with the Baobab tree (Adansonia digitata) in Africa; waterlogging not tolerated; tolerant of slightly saline soils; drought-tolerant; wood is easy to polish and termite-resistant; not an N₂ fixer.

• Terminalia amazonia (J.F.Gmel.) Exell

• (Combretaceae)

Origin and Distribution:

South America - Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela, the Guyanas; north through Central America to Mexico.

Ecology:

Occurs in wet forests and swamps or open savannahs; mainly at lower elevations in the tropics from near sea level to below 1000 m.

Plant Characteristics:

Moderately fast growing; evergreen tree with a large crown; up to 40 m tall; wide range of soils, including poor sands and clays, except the drier sites; seed propagated.

Main Uses:

Shade tree (coffee, cacao); good quality wood; used for making high quality furniture, cabinets, flooring, ship building, tool handles, veneer etc.; bark a source of tannins.

Comments:

Little studied; wood heavy, hard, and strong; elastic; moderately durable, resistant to dry woodborers, moderately resistant to fungi and termites.

Related Species

• Terminalia brownii Fres. Tropical Africa: Nigeria and Cameroon to East Africa. Occurs in the dry to moist tropical areas, usually at elevations up to 600 m. Deciduous shrub or small tree up to 15 m tall. Used as fodder (leaves), fuelwood and charcoal; coppiced when young.

• Terminalia ivorensis A. Chev. Western tropical Africa; large deciduous tree; 15 to 46 m tall; fast rate of growth; seed propagated; strong light demander and a good colonizer of abandoned farmlands; firewood and charcoal; shade (coffee, banana and cocoa) or shelter; intercropping.

• Vitellaria paradoxa C.F.Gaertn (The Shea Butter Tree)

• (Sapotaceae)

Synonyms:

Butyrospermum niloticum Kotschy, B. paradoxum (C.F.Gaertn.) Hepper

Origin and Distribution:

Indigenous to the Guinea and Sudan savanna zone from Senegal to Sudan, and to western Ethiopia and Uganda; characteristic tree of West African savanna.

Ecology:

Occurs in open sites and parkland savannah; altitude 100–1200 m; mean annual temperature 24–32 °C; mean annual rainfall 600–1400 mm; prefers dry and sandy clay soils.

Plant Characteristics

(see Figure 9.11): Small to medium-sized tree, 10–15 (max. 25) m tall; much branched, dense, spreading, round to hemispherical crown; light-demanding; seed propagated.

Main Uses:

Flowers and fruits are important foods; shea butter extracted from the nuts is one of the widely used and inexpensive vegetable fats in Sahel (see Figure 22.8); apiculture; firewood (excellent quality); leaves, bark, and shea butter used in traditional medicines; soil improver, control soil erosion; suitable for intercropping; increasingly being used in cosmetics.

Comments:

The shea tree, listed as “vulnerable” in the IUCN Red list, is one of the most important sources of vegetable oil in rural areas of the savanna zone of West Africa. Shea butter is a useful cocoa-butter substitute.

• Ziziphus mauritiana Lamk (Ber or Desert Apple)

• (Rhamnaceae)

Synonyms:

Ziziphus jujuba (L.) Lam., and several others.

Origin and Distribution:

Native of South and Central Asia; now found in East and West Africa.

Ecology:

Usually occurs in the semiarid tropics in regions receiving 250–500 mm annual rainfall at altitudes of 0–1500 m on light, sandy to medium, loamy, well-drained, moderately saline soils.

Plant Characteristics:

Fast growing, thicket-forming shrub or tree; single or multi-stemmed; thorny; 2–12 m in height; deciduous during the dry season; deep rooted; propagated by seedlings, root suckers, and direct sowing; hardy tree; survives under extreme temperatures.

Main Uses:

Edible fruits; live fences; fodder; sericulture; host for shellac insects; apiculture; fuelwood (sapwood has 4900 kcal kg^–1); good charcoal; poles and posts; wood for construction; sand-dune fixation; shade tree; ornamental; living fence (spiny stems deter livestock).

Comments:

Commonly used for windbreaks; coppices; noxious weed in Australia; invasive in parts of southern Africa and on some Pacific and Indian Ocean islands.

Related Species

Ziziphus nummularia (Burm. f.) Wight et Arn; syn. Rhamnus nummularia Burm.f

Native to the Indian sub-continent (Figure 13.A.I.22). Found in the semiarid tropics and highland subhumid tropics. Thorny; multi-stemmed; to about 3 m in height; deciduous in dry season; propagated by seedlings and root suckers. Edible fruits; fodder; fuelwood.

Figure 13.A.I.22

Zizyphus nummularia with turmeric (Curcuma longa) as the understory crop in Rajasthan, India. (Photo: ICRAF/World Agroforestry)

1.2 Appendix II Shade-Tolerant Specialty Species

As noted in Section 13.4.1 (Shade-Tolerant Specialty Crops and Medicinal & Aromatic Plants), several so-called specialty crops are cultivated in agroforestry systems, especially in the tropics. They broadly fall under four categories: (1) Commercial crops trailed onto woody perennial support trees (perennial vines) – Prominent examples: black pepper (Piper nigrum) and vanilla (Vanilla planifolia) ; (2) Perennial rhizomatous cash crops that are grown under the shade of trees in natural stands and harvested like annuals – Prominent examples: cardamom (Elettaria cardamomum) and large cardamom (Amomum subulatum) ; (3) Rhizomatous, botanically perennial species that are cultivated as annuals under planted or natural stands of trees -- Prominent examples: ginger (Zingiber officinale) , turmeric (Curcuma longa) , ginseng (Panax spp.); and (4) Medicinal and aromatic plants , mostly annuals but also including some trees that are harvested annually and nondestructively like fruit trees – Prominent examples: Allspice (Pimenta spp.), clove (Syzygium aromaticum), and nutmeg (Myristica fragrans) .

Out of the examples of ten species mentioned above, considerable commodity-centric information exists on some of the prominent ones such as black pepper and cardamom, whereas information on the commercially less-prominent and less widely cultivated ones such as ginseng and allspice is relatively limited. Brief descriptions of the ten species of the four categories identified are given below in the order in which the species are mentioned above.

1.2.1 Black pepper (Piper nigrum, Family: Piperaceae)

Black pepper, known as the king of spices, is one of the oldest spices of extraordinary importance in international trade. It is a native of the Western Ghats in peninsular India; is cultivated in India, Southeast Asia, and the New World Tropics. The plant is a perennial woody climber (Figure 13.A.II.1) growing up to 10 m height and is adapted to humid tropical climates with a well-distributed annual rainfall of 2,000 to 2,500 mm, on fertile well-drained soils; does not withstand prolonged flooding or drought. Pepper is cultivated in commercial plantations or as a component of the mixed species tropical homegardens and coffee and tea plantations. Being a climber, it needs to be trailed on to a support (called “standard”) such as a wooden pole. The various MPTs in homegardens (Chapter 7) are used as support trees in smallholder production systems, whereas in commercial plantations, support trees are planted specifically for the purpose, the most common being Erythrina spp. and Gliricidia sepium . Fast growth, ease of propagation, light crown, tolerance to pests and diseases rough and non-exfoliating bark, and a deep root- system are the desirable attributes of a support tree for trailing pepper vines. The pepper vine is propagated by stem cuttings. Flowering and fruiting start in about three years after planting; fruits (spikes) ripen in four months after flowering, full production is attained in about five years and continues for up to 25 years. The plant is susceptible to several fungi and insects.

Figure 13.A.II.1

Black pepper around the trunks of trees, with cardamom leaves in the foreground, Kerala, India (Stock Photo)

(Various photos of pepper can be found in Chapters 7, 8, and Appendix I of this chapter)

1.2.2 Vanilla (Vanilla planifolia, Family: Orchidaceae)

Vanilla yields vanillin, the popular flavoring agent of commerce, from the fermented and processed beans (pods) of this orchid. Being the only member of the family Orchidaceae yielding a spice , it is called “orchid spice .” The plant originated in Mexico and was introduced to many tropical countries in Asia and Africa, Madagascar being the major producer in the world today. The plant is a perennial succulent vine, and, like black pepper, it requires light overstory shade, a support for trailing (Figure 13.A.II.2) and humus-rich soil. Propagation is by stem cuttings; mulching is important. Plants flower in about four years. Natural pollination is impossible because the stamen and stigma are separated by a rostellum. In Mexico, some cross-pollination happens by bees, but commercially hand pollination is carried out; an individual worker handles 1000 to 2000 pollinations per day. Fruits mature in 7–9 months and should be harvested before they are fully ripe and are cured by alternate wetting and drying.

Figure 13.A.II.2

Vanilla trailing on the support tree (Talipariti tiliaceum) in Madagascar. (Photo: Dominik Schwab and Annemarie Wurz, Univ. of Goettingen, Germany) (Also see Figures 8.16, 8.17; Chapter 8)

1.2.3 Cardamom (Elettaria cardamomum , Family: Zingiberaceae)

Cardamom , known as the “queen of spices,” is an important spice used for flavoring, chewing, and medicinal purposes, and is the second most important spice crop after black pepper. Sometimes it is referred to as small cardamom – to distinguish it from its larger variant, Amomum spp., known as large cardamom that is a taller plant and produces larger capsules. E. cardamomum produces the principal cardamom of commerce. The plant is indigenous to the mid-elevation moist evergreen forests of the Western Ghats in peninsular India; grows well on warm (10 to 35 °C) and humid (with >1500 mm of evenly distributed rainfall) mountain slopes (600–1500 m elevation), beneath a canopy of evergreen trees. Other major producers of the crop include Guatemala, Indonesia, and Tanzania. E. cardamomum is a perennial herb, 2 – 5 m tall; has a branched subterranean rhizome, from which arise 10 – 20 erect leafy shoots, and the panicles arise from the base of the shoots (Figure 13.A.II.3). The fruit is a trilocular capsule, pale green when mature; the seeds are about 3 mm long, dark brown, and aromatic. Cardamom is propagated by planting a section of the rhizome called the “bulb.” The plant starts bearing in about 3 years and attains full bearing in 7–8 years after planting, and economic bearing lasts for about 15 years. The plant grows best under light shade provided by trees (Figure 13.A.II.4) thus, cardamom cultivation is a “typical” agroforestry practice.

Figure 13.A.II.3

Cardamom in full bloom: panicles originating from the leaf axils at the base of the plant in Guatemala. (Photo: PKR Nair)

Figure 13.A.II.4

Cardamom under shade trees in Kerala, India. (Photo: BM Kumar) – See also Figure 13.A.II.1

1.2.4 Large Cardamom (Amomum subulatum , A. aromaticum, Family: Zingiberaceae)

Large cardamom, also known as “black cardamom ,” is a native of the sub-Himalayan ranges, and India is its largest producer and exporter. Several species of the genus Amomum are distributed all over the mountainous areas from the Himalayas to southern China, Thailand, and Cambodia. Pods are used as a spice , much like the green Indian (small) cardamom pods but have a distinctly strong and smoky flavor and aroma. Just like small cardamom , large cardamom is a sciophyte (shade-loving crop) and it grows well under moderate to dense shade (25 – 70% light interception). Himalayan alder (Alnus nepalensis ), a deciduous, nitrogen-fixing (actinorhizal) and fast-growing tree, is the most prominent shade tree; some fodder trees are also used for shade. The shade trees also serve as a fuelwood source for curing the cardamom , as well as yielding fodder and timber (See a photograph of Amomum subulatum given as Figure 8.15).

1.2.5 Ginger (Zingiber officinale , Family: Zingiberaceae)

The ginger plant, an important source of spice as well as herbal medicine, originated in the Indo-Malayan region but is now widely distributed in many countries around the globe. The dried rhizome constitutes the ginger of commerce. Ginger is slender perennial herb to 1 m tall; the rhizomes are thick and hard; is cultivated in the tropics under the partial shade of trees, from sea level to about 1500 m elevation and 1500 – 2500 mm annual rainfall, on soils that are deep, well-drained, and high in organic matter; does not withstand waterlogging. Is propagated by 3 – 5 cm long rhizomes (called setts); they germinate about two weeks after planting. The crop matures in about 9 months. Being a shade-tolerant plant, it is usually grown as an understory crop in the homegardens and tree plantations (Figure 13.A.II.5). Many traditional cultivars are important components of agroforestry, but only limited attempts have been made to evaluate the effects of varying shade levels on ginger productivity.

Figure 13.A.II.5

Ginger as the understory species in a three-year-old stand of Ailanthus triphysa trees in Kerala, India. (Photo: BM Kumar)

1.2.6 Turmeric (Curcuma longa , Family: Zingiberaceae)

Turmeric or “the golden spice of life”, is a perennial herb (Figure 13.A.II.6) which originated in South and Southeast Asia, but is cultivated in the tropical and subtropical regions all over the world. Turmeric powder is extensively used as a food coloring and flavoring agent and it has many medicinal properties too, which can be attributed to a chemical constituent, curcumin (diferuloyl methane) – a non-steroidal, anti-inflammatory agent (3–4% by weight). Being a shade tolerant crop like ginger , turmeric is under-planted in several agroforestry systems in the tropics. Although many national research institutes have standardized the industrial turmeric production practices (e.g., Ravindran et al. 2007), aspects relating to shade requirement of the crop have not received adequate scientific attention, even though turmeric is a prominent understory crop in many traditional land-use systems.

Figure 13.A.II.6

Turmeric under oak trees in North Florida, USA. (Photo: PKR Nair) (Also see Figures 12.6 and 13.A.I.22)

1.2.7 Ginseng : Panax ginseng (Korean ginseng ); P. quinquefolium (American ginseng), Family: Aralioideae

Ginseng is the root of plants of the genus ginseng , of which several species exist. It has been used in traditional medicines over centuries in Asian countries (mainly Korea and China) for its reported medicinal values. It is also cultivated in the eastern and central US and Canada and is found in rich, cool woods (Figure 13.A.II.7). In Korean cuisine, ginseng is used in various side dishes and soups), as well as tea and alcoholic beverages. Although commonly used as a dietary supplement, ginseng has not been approved by the US Food and Drug Administration (FDA) as a prescription drug. The shape of the root varies among species and has been used to distinguish types of ginseng. The root is most often available in dried form, either whole or sliced. Ginseng leaf, although not as highly prized, is sometimes also used. The Ginseng Growers Association of America, Inc. (GGAA: https://ginsengamerica.org) is a non-profit organization that was founded in the interest of growers and consumers of American ginseng represents ginseng growers in the United States, primarily in the state of Wisconsin. The short plant grows 3 to 7 compound leaves that drop in the fall and bears a cluster of red or yellowish colored fruits from June to July. It prefers a cool climate and grows well in the summer months under the trees and is commonly mentioned as an example of the Forest Farming practice of agroforestry in North America (see Chapter 10).

Figure 13.A.II.7

Ginseng under trees (Forest Farming) in Wisconsin, USA. (Photo: USDA/National Agroforestry Center)

(Also see Figure 10.12, Chapter 10)

1.2.8 Allspice (Pimenta dioica , Family: Myrtaceae)

Allspice , known also as pimento or Jamaican pepper, is the dried, unripe berries of a small tree Pimenta dioica , and is a preferred culinary spice of commerce. It combines the flavors of cinnamon (Cinnamomum zeylanicum), clove (Syzygium aromaticum ), and nutmeg (Myristica fragans), and hence the name. The plant, native to West Indies and Central America, is a small evergreen tree, up to 9 m in height, with a slender erect main trunk that is profusely branched in its upper part (Figure 13.A.II.8). In its natural habitat, it grows in hot humid (annual rainfall about 1500 mm) lowlands (up to 500 m altitude) in fertile well-drained soils. Propagation is by seed, or sometimes vegetatively by grafting or budding; starts flowering in 5 – 6 years, attaining full bearing in 10 – 15 years, and lasting for the subsequent few decades. Allspice is usually grown in agroforestry combinations in homegardens with bananas, maize , and other common crops, and in silvopastoral systems in commercial plantations.

Figure 13.A.II.8

Allspice tree in Jamaica (Stock photo)

1.2.9 Cinnamon (Cinnamomum zeylanicum)

Cinnamon bark (quills) is used as a condiment for flavoring cakes, confections, and curries. Cinnamon oil distilled from the bark and dried leaves is used in perfumes and in the synthesis of vanillin. The plant is a native of Sri Lanka and the Western Ghats of peninsular India. Now it is cultivated also in southeast Asia and Seychelles, but Ceylon (Sri Lanka) cinnamon is reputed to be of the best quality. It is an evergreen tree that grows up to 15 m tall if left undisturbed. When cultivated, the stems are repeatedly cut for extracting the bark, giving the plant a bushy appearance. The leaves are stiff and aromatic and reddish brown when young. The best cinnamon is grown at low altitude, but the plant grows up to 1800 m elevation from sea level. The plant is adapted to light overstory shade. It is propagated by seed. The stems are cut when they are about 2 m high and 2 – 5 cm in diameter, which is after about 2 years of growth. Harvesting is done during the rainy season, which facilitates easy peeling of the bark. The peeled bark is fermented in heaps, and when it contracts to a quill or pipe, is packed with multiple quills rolled together. Cinnamon is commonly grown in smallholder farming systems including homegardens and other agroforestry systems (Figure 13.A.II.9).

Figure 13.A.II.9

Three-year-old cinnamon (Stock photo)

1.2.10 Nutmeg (Myristica fragrans , Myristicaceae)

Two important spices are obtained from the fruits of this tree: nutmeg , the dried seed, and mace, the dried aril, and both are used for medicinal purposes and in sauces and ketchup. It is a native of the eastern island of Moluccas and is now cultivated mainly in Indonesia and other parts of southeast Asia and parts of India and the West Indies. It is a small tree, about 10 m tall, with thick and luxuriant foliage. Flowers are unisexual; the male and female flowers are produced on separate trees, and sex differentiation is difficult before the tree flowers. The fruit is a fleshy, pale yellow, smooth drupe. The plant prefers rich well-drained soil, partial shade, and a hot humid climate with no pronounced dry season. Normally propagated by seed, but vegetative propagation (inarching) is getting popular to overcome the difficulty posed by 6 – 8 years of delay in sex differentiation; attains full bearing in about 15 years after planting, and lasts for several decades. Nutmeg is usually grown in agroforestry combinations (Figure 13.A.II.10) in association with (under) larger trees.

Figure 13.A.II.10

Nutmeg tree interplanted under coconut palms in Kerala, India. (Photo: ICRAF/World Agroforestry)