| Firewood Crops - Shrub for Energy Production - Volume 2 |
|Fuelwood Species for Humid Tropics|
Bursera simaruba Sarg.
Bursera gummifera L., B. ovalifolia Engler, Elaphrium simaruba Rose
Gumbo limbo, gum-elemi, gumtree, West Indian birch, red birch, almacigo, indio desnudo, palo mulato, galo de incienso, turpentine tree, and many others
This handsome tree is esteemed for fuel and for living fence posts throughout Central America and the Caribbean. So far, however, it is virtually unknown elsewhere. It is easily propagated - green branches thrust into the ground take root quickly and grow vigorously. The trees regenerate swiftly after cutting. In fact, even trees blown down by winds send up shoots, which soon become trunks as big as the original.
The gumbo limbo as it grows in forests is an erect, straight, resinous tree reaching 20-30 m, with a stout trunk (to 75 cm) that is often forked about 2 m from the ground, forming thick vertical branches that fork again higher up. The bark, which peels off in thin flakes, is typically copper colored (sometimes silvery) and glossy. When growing in the open, the branches spread and form a broad crown. The tree is bare during the cool, dry season. The leaves are compound and have a turpentine odor when crushed.
This handsome tree is native to and esteemed in areas from central Florida through the Bahamas and West Indies and from southern Mexico to the northern parts of South America.
Use as Firewood
The wood has a high moisture content, but when thoroughly dry it is commonly burned as firewood and charcoal. Because of its flammability, Indians of Yucatan use it for kindling. The wood has a specific gravity, green and oven dried, of 0.30-0.40.
No studies have been made of the potential firewood yield. In Belize, surveys have shown populations of up to 57 trees per ha in the wild.
· Wood. The wood seasons well, with slight shrinkage; is easily worked; saws, planes, and polishes satisfactorily; holds nails firmly; and is used commercially for a veneer that resembles
paper birch and for plywood for interior use. It is fairly strong, but is not durable for outside use, being attacked by borers, beetles, and termites. Locally, it is made into boxes and crates, soles for sandals, light furniture, and matchsticks and toothpicks.
· Beautification. The gumbo limbo is much used as an ornamental. In southern Florida it is planted as a landscape tree in new developments and along streets, mainly because of its quick growth, but also because of the newly awakened appreciation of native species. It has long been planted as a living fence throughout the Caribbean area.
· Resin. The aromatic resin, which oozes from an incision as a thick, amber gum, is concentrated and dried and the chips offered as tithes or burned as incense in South American churches.
· Temperature. Gumbo limbo requires a subtropical or tropical climate. Fully grown trees stand occasional brief winter frosts.
· Altitude. It is found from sea level to 1,800 m elevation in Guatemala, but generally occurs below 1,000 m.
· Rainfall. The tree abounds where annual rainfall averages 500-1,400 mm.
· Soil. Gumbo limbo endures extreme soil types ranging from fertile, moist forest habitats to dry, barren limestone, but it grows best in rich lowlands. Under the severely arid conditions of some Caribbean islands it is rather stunted and crooked, but survives. It has a high degree of salt tolerance.
While the tree reseeds itself in its natural areas, it is seldom deliberately propagated by seed.
· Ability to compete with weeds. Being a forest tree, the gumbo limbo tolerates shade at all stages of growth. It is not retarded by the shade of competing vegetation even in the juvenile period.
Pests and Diseases
The resin is a natural insect repellent, and no pests or diseases are reported in available literature.
Apart from cold sensitivity, the handicaps seem to be only the brittleness of branches, which may be snapped off by strong gusts of wind; the perishability of exposed wood; and the discoloration of the timber by the sap-stain fungi to which it is prone because of its high moisture content. (Such staining can be avoided by immediate kiln drying or by immediate spraying of the cut logs with a fungicide.)