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close this bookCERES No. 096 - November - December 1983 (FAO Ceres, 1983, 50 p.)
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Multipurpose salmwood attracts attention as agroforestry candidate

A fast-growing tree from Latin America is showing considerable promise both for commercial plantations and for agroforestry. Despite its valuable properties, however, Cordia alliodora, known in the Americas as laurel and in Britain as salmwood, has been tried outside South America on only a small scale.

Cordia wood commands a high market price because it seasons rapidly and is easy to work. It is suitable for furniture, veneer plywood, boat decking and railway sleepers. Though relatively abundant in South America, it is not generally available for export because of strong local demand.

Such a situation was forecast in a 1972 study which concluded that: "if Cordia is ever to become a major export wood, large scale forests must be established. Individual tree growth data suggests that such plantations will be economically feasible if factors influencing variability can be identified and controlled" (1). But although the species has been under testing since then, results are not yet widely available and large-scale plantations are still a thing of the future.

Cordia is found from Mexico to northern Argentina at altitudes ranging from sea level to 1 900 metres. It thrives in a wide variety of soil conditions though it prefers deep, well-drained soils. Due to its intolerance for shade, its establishment in natural forests probably depends on accidental gaps or human intervention.

Conscious of the value of its timber, South American farmers generally leave regenerated Cordia when clearing their fields and pastures. It is often deliberately introduced as shade cover for coffee, cocoa and sugar cane because of its light crown, which does not cut out the tight entirely.

Cordia can also be grown in highly productive agroforestry combinations with fruit trees and agricultural crops. Commenting on agroforestry trials being carried out in Costa Rica, John Beer of the Tropical Agricultural Research and Training Center (CATIE) reports: "These associations often show a structure that imitates the natural forest of this region, in other words a multistrata system is cultured with the crowns of the timber-producing species forming the upper layer, leguminous shade trees, bananas and fruit trees forming the central layer and finally the agricultural crop, such as coffee or cacao, being grown at or near ground level."

Robin Levingston of FAO's Forestry Department suggests that salmwood could even be tried in combination with rice, maize or cassava, and as a support for pepper vines, assuming that the spacing is right. Levingston describes Cordia as "a moderately fast growing species, but in the upper moderate sector." Naturally this is dependent on the climate and on the characteristics of the individual Cordia. One plant at the: University of Michigan's botanical gardens grew from seed to a height of more than three metres in one year. Normal growth is about one and a half to two metres a year for the first five years. At maturity, under optimum conditions, Cordia can reach a height of more than 30 metres and a diameter of a metre or more.

Cordia requires relatively little silvicultural management, partly because of its ability to grow as an isolated tree and yet form a straight, self-pruned trunk. It suffers from no known serious pests, although under very humid conditions it can be damaged by pink disease. Aside from the value of the timber itself, the tree can serve a useful role in combatting erosion. In South America, various species have been put to work as "living" fence posts.

In the last analysis, however, Cordia's suitability for agroforestry comes down to a question of hard cash. In coffee plantations and sugar cane fields in Costa Rica, salmwood timber volumes of up to 130 cubic metres per hectare have been reported, worth approximately $8 000 per hectare if sold at local sawmills. The Costa Rica trials are attempting to measure the annual increase in wood value against the increase or decrease in crop value in the area influenced by the trees. On one experimental plot of Cordia and sugar cane, John Beer reported: "The yields of five-by-five metre plots beneath mature trees, with a stand density equivalent to 161 stems per hectare, were 85 percent of the control yields. But more research is needed for an economic comparison between the reduced profit from cane and the additional value of the wood."