Enterolobium cyclocarpa (Jacq.) Griseb.

Enterolobium cyclocarpum is one of the largest trees in the dry forest formation, reaching up to 40 m in height and 3 m in diameter, with a huge, spreading crown. Older E. cyclocarpum trees develop small buttresses and produce large roots that run along the surface of the ground for 2-3 m. Sidewalks, roads, or foundations may be cracked or raised by E. cyclocarpum trees growing close by. The bipinnate compound leaves of E. cyclocarpum have 5 opposite leaflets. The small white flowers occur in compact, round heads. Seeds contained in distinctive, thickened, contorted, indehiscent pods that resemble an ear in form; seed 20 x 15 mm, ovate, compressed, dull, reddish-brown, with 100% pleurogram, marked with a yellowish band on each face, punctiform apical hilium concealed or not by whitish funicle; adult trees produce about 2000 pods, each with 10-16 seeds.

The small, white flowers are borne in clusters or heads at the base of the leaves. Flowering takes place in March and April during the regrowth of new leaves after the leafless dry season. There is no indication in the literature as to what age flowers 1st appear. Seed dissemination is mainly by cattle, horses and wild ungulates, attracted by the syrupy pulp of the fruits.

E. cyclocarpum tolerates alkaline, calcareous and even acidic soils. Medium-textured soils are probably best, but eroded Ultasols, deep moist clays, shallow sandy clays and porous limestone all allow good development.

Colonizing a wide range of habitats, E. cyclocarpum is a climax species in subtropical, dry forest zones, restricted to disturbed areas in wetter forest types. It is a dominant species in all the tree associations in which it is found. In Mexico, it is found in association with Ficus mexicana, Sideroxylon capirit, Trichilia hirta, Ceiba pentandra, and others. Dry seasons of 1-6 months are usual in most of its habitats.

Although E. cyclocarpum is generally considered to have been introduced throughout the tropics mainly as a roadside or garden tree, it is apparently little known or used outside its native range and has never been planted on a large scale, although it has been tested in plantations in Puerto, Ghana and sporadically elsewhere. The history of introductions remains poorly documented and it is unclear exactly how widely distributed this species is, at least in Africa and Asia. It is without doubt widespread and common throughout the Caribbean.

E. cyclocarpum is propagated through seeds. Seeds are most easily collected from pods that have fallen to the ground. Collected seeds require pretreatment before sowing to allow water to penetrate the seed coat. Manual scarification is effective, as is treatment with hot water or concentrated sulphuric acid. E. cyclocarpum trees coppice, and even large trees sometimes sprout when cut. There has been no report on grafting or rooting of cuttings. Natural regeneration is infrequent for several reasons. The seeds are spread principally by grazing animals, and after germination are always browsed off. They are also susceptible to fire, excessive shade, drought and competition from grasses.

Spacing of 4 x 4 m with thinning on a rotation of 25-35 years is recommended. E. cyclocarpum is shade intolerant. The tree must receive adequate sunlight as a dominant or codominant from the sapling stage onwards. Careful weeding of the plantation is essential during the early years. Pruning can improve the length and form of the bole. It resprouts vigorously after coppicing or lopping. Little information is available, however, on its response to repeated cutting.

E. cyclocarpum has no widespread or serious disease or pest problem. Parrots often prey on the green pods, and the gall-forming moth, Asphondylia enterolobii, may disrupt fruiting. Occasional attack by a fusarium fungus may cause the affected limbs to fall from mature trees.

Seed storage behaviour is orthodox; seeds tolerate desiccation to 10.7% mc. Seeds remain viable for several years under cool, dry conditions and can be easily stored under normal conditions. There are 900-1200 seeds/kg.

Shade or shelter: The wide-spreading canopy of E. cyclocarpum makes it an ideal shade tree for livestock in pasturelands and perennial crops such as coffee. Nitrogen fixing: E. cyclocarpum is a nitrogen-fixing species. Ornamental: A popular tree for roadsides and urban planting. Intercropping: The ability of E. cyclocarpum to fix nitrogen and to sprout vigorously when coppiced point to its possible role as a hedgerow species in alley-cropping systems.

Food: Immature pods are cooked as a vegetable, or the seeds are toasted and ground. Fodder: Large quantities of highly palatable and nutritious pods containing a sugary pulp are produced by the tree, and are consumed readily by livestock. The foliage is also palatable, though to a lesser extent than the pods. Fibre: The wood of E. cyclocarpum has been found excellent for producing quality paper. Timber: E. cyclocarpum heartwood is reddish-brown, coarse-textured and moderately durable. The wood is resistant to attack by dry-wood termites and Lyctus, and can be used in house construction as well as in interior elements, including panelling. The white sapwood is susceptible to insect attack. The wood may also be used for boat building, because of its durability in water. Tannin or dyestuff: Tannin from the pods and bark is used in soap making. Medicine: Bark extracts are used medicinally against colds and bronchitis.