| Calliandra calothyrsus - Production and use: A Field Manual |
Hoang Xuan Ty, Endang Hernawan, M. de S. Liyanage, Mapatoba Sila, Hikmat Ramdan, A. Ng. Gintings, Yayat Hidayat, Adji Setijoprodjo, Ralph Roothaert, Rodrigo Arias, and Duncan Macqueen
Calliandra calothyrsus is a popular multipurpose tree because it is easy to establish, grows quickly, and resprouts after repeated harvests. In many parts of Indonesia, these trees are planted for fuelwood and livestock fodder, for soil conservation and improvement, and as a nurse tree for other species. Producing flowers throughout the year, C. calothyrsus is also an important species for honey production. The successful use of this species in Indonesia has stimulated wider interest, and trials are currently underway in other countries to evaluate the potential of C. calothyrsus, particularly for soil improvement and livestock fodder. The use of C. calothyrsus in animal production systems is discussed separately in Chapter 5.
Fuel and pulpwood
More than 30,000 hectares of C. calothyrsus fuelwood plantations have been established on private and public lands in Java, Indonesia. The dense wood (specific gravity of 0.5 to 0.8) dries rapidly and burns well, producing about 4,600 kcal of heat per kg of dry wood and 7,200 kcal of heat per kg of charcoal. For fuelwood production, C. calothyrsus is usually planted at a spacing of 1 x 1 m or 1 x 2 m. To encourage rapid resprouting, trees should be cut to a height of 30 to 50 cm at the end of the dry season. Annual fuelwood yields range from 5 to 20 m3/ha from one-year-old plantations and 30 to 65 m3/ha from 20-year-old plantations (NAS 1983).
In the Pintulung Valley of South Sulawesi, Indonesia, C. calothyrsus plantations are a major source of fuelwood for homebased production of palm sugar (Arenga pennata). Farmers prefer Calliandra fuelwood because it burns hotter then other woods end thus less time is required to prepare the palm extract. Calliandra calothyrsus wood is also burned to smoke sheet rubber, dry copra, and heat brick and tile ovens.
A paper company in West Java, Indonesia, mixes pulp of C. calothyrsus with pulp of Paraserianthes falcataria and Leucaena leucocephala. With a cellulose content of 44 to 51 percent, C. calothyrsus is a suitable component for paper pulp (NAS 1983), but its low density and folding endurance limit its usefulness. It can provide a filler, but should comprise no more than 10 percent of total pulp. When planting C. calothyrsus for pulpwood production, a 2 x 2 m spacing (2,500 trees/ha) is recommended.
Calliandra calothyrsus is becoming an important source of forage for honey bees in Indonesia. Honey production increased from 650 tons in 1989 to 1,300 tons in 1994, and Indonesian farmers currently manage about 50,000 hives. Under farm management, it is estimated that bees can produce 1 ton of honey a year from 1 ha of C. calothyrsus forage (Sila, 1996).
An interesting secondary benefit from the introduction of C. calothyrsus for honey production has been improved pollination of coffee trees. In Indonesia's Pintulung Valley, growers traditionally harvested coffee only once a year. With the establishment of C. calothyrsus plantations and the resultant increase in bee populations, farmers now harvest coffee two to three times a year (Sila, 1996).
In Sri Lanka, C. calothyrsus has been planted in coconut plantations to reduce weed growth, conserve soil moisture, and improve soil structure and fertility. For maximum biomass production, the Calliandra is planted at a density of 2,500 trees/ha and pruned at four-month intervals to a height of I m above the ground. The trees grow well under mature coconut planted at a density of approximately 160 trees/ha. The Calliandra produces about 5 tons/ha dry matter, which provides the annual nitrogen requirement of the coconut trees—30 kg of green manure is spread around each coconut tree. In addition to providing nitrogen, the C. calothyrsus leaves decompose slowly and make a good mulch for conserving soil moisture and suppressing weed growth during the dry season (Liyanage and Abeysoma, 1996).
Farmers plant C. calothyrsus as a nurse tree in coffee plantations in South Sulawesi, Indonesia, and also in some areas of Guatemala and Costa Rica. As plantations mature in Guatemala and Costa Rica, farmers replace C. calothyrsus with larger shade trees such as Inga, Gliricidia, and Erythrina species. In Sri Lanka, farmers have expressed an interest in using C. calothyrsus as a medium-sized shade tree in tea plantations.
In West Java, Indonesia, farmers plant C. calothyrsus as a nurse tree in plantations of high-value timber trees such as Agathis loranthifolia an d Tectona, Swietenia, and Pinus species. The C. calothyrsus is planted along contour lines in dense rows between rows of the main timber species. The rows of nurse trees are usually spaced at 2.5 to 3 m from the timber trees, depending on the slope. The Calliandra trees are pruned regularly, and the pruning material is returned to the soil as green manure and mulch. The nurse trees suppress weed growth, prevent soil erosion, and add fertility to the soil.
Calliandra calothyrsus also has good potential for intercropping with food plants such as maize, rice, or groundnuts. Preliminary results from hedgerow-intercropping trials indicate that the trees should be planted at a 2.5 m spacing within rows and pruned to a height of 0.5 m. The biomass should be incorporated into the soil before planting the food crop. Rows of C. calothyrsus may have to be pruned once or twice more during the growing season to reduce competition for light and soil moisture. Pruning frequency depends on the rate of tree growth, the availability of soil moisture, and the height of the food crop (Satjapradja and Sukandi, 1981).
Farmers in Indonesia interplant C. calothyrsus and other shrubs with food crops on hillsides (slopes less than 45 percent) in contour rows 1.5 m to 2 m apart. The hedgerows are pruned for mulch during the dry season and green manure during the wet season.
In southern Cameroon, C. calathyrsus has proven to be an excellent species for enhancing the fertility of acid soils. Trees planted at a spacing of I x I m (10,000 trees/ha) and managed as a rotational fallow can increase the yield of subsequent food crops 1.5- to 2-fold compared with yields following natural fallows of the same duration (Duguma, 1996). Trees are cut to ground level during the cropping phase and allowed to grow during the fallow phase.
Preliminary trials in Vietnam indicate that fallow periods can be reduced from 10-15 years to 4-5 years without reducing soil fertility by replacing natural fallows with C. calothyrsus. In this improved-fallow system, farmers plant 5,000 to 10,000 Calliandra seedlings/ha during the last crop rotation (Ty, 1996).
Erosion and landslide control
Calliandra calothyrsus is planted on steep hillsides in South Sulawesi, Indonesia, to control soil erosion and prevent landslides. The species works well for this purpose because trees can be direct seeded, they grow quickly, and they continue to produce coppice regrowth after repeated harvests. Planted on hillsides along the contour, the trees capture the top soil and eventually form natural terraces.
Rehabilitation of Imperata grasslands
In North Sumatra and South Sulawesi, Indonesia, C. calothyrsus has been used successfully to rehabilitate unproductive acid soils infested with alang-alang (Imperata cylindrica). These areas have been transformed into productive grazing lands for sheep and goats.
Intensive weeding is required to establish C. calothyrsus plantations under these difficult conditions. Trees are planted at a spacing of 5 x 5 m and the alang is weeded from a circular area of 60 cm diameter around each seedling until the crown cover of the trees begins to close, usually one to two years after planting. As the tree crowns grow together, the amount of sunlight reaching the understory is reduced, and the alang-alang disappears (Sila, 1996).