Roble is native to Puerto Rico and widely distributed through the West Indies from Hispaniola to Grenada and Barbados. It is also naturalized in Bermuda and planted in southern Florida (16).
In Puerto Rico, it is widespread in abandoned pastures and secondary forests and found in dry or wet natural forests, except for the highest elevations in the Luquillo Mountains and the Cordillera Central. Elsewhere in the Caribbean, roble is particularly common in dry, coastal woodlands and in secondary forests.
Reasons: Extremely widespread and often very common throughout the Antilles (Gentry 1992). Native from Hispaniola, Puerto Rico, and Virgin Islands through the Lesser Antilles to Grenada and Barbados. In Puerto Rico, roble grows from sea level to 3000 feet in elevation and is widely distributed (Wadsworth 1943).
In Puerto Rico, roble is found on sand, limestone, and heavy clay soils, acid or alkaline in reaction, and residual, alluvial, or colluvial in origin. It appears to grow best, however, on deep clays. Roble is a cosmopolitan species and is found on all soils presently identified in Puerto Rico. The most common soil order on the island is Inceptisols. Physiographically, it is most common on slopes and ridges (19) but is also found on flats adjacent to river beds (9). In general, it is tolerant of degraded sites and abandoned farm lands where it tends to form nearly pure stands.
In Puerto Rico, roble is planted on poor sites to provide cover and to improve the soil. It is recommended for planting on uniform and convex slopes and ridges, where trials have shown it to be a promising species for reforestation (20). It has also done well on humid, waterlogged sites.
Uses: Folk medicine, Building materials/timber, Cultivated ornamental
Comments: Widely cultivated as an ornamental; also used for timber. According to Hodge and Taylor (1957 in Gentry 1992) it lasts especially well in salt water and is thus used for the ribs and sides of dugouts on Dominica, the wood also being employed in the construction of mortars, wooden bowls, and floors. It is also used medicinally. For example, on Dominica a plaster of the bark is used to cure corns and the leaves as a poultice on sores (Hodge & Taylor 1957 in Gentry 1992), and the leaves and bark are boiled as a cure for colds on St. Christopher (Cooley 8797 cited in Gentry 1992).
In Puerto Rico, roble is found principally in the Subtropical Dry, Subtropical Moist, and Subtropical Wet life zones (12,15) where the annual rainfall varies from about 850 to 2500 mm (33 to 98 in). Temperature ranges from a mean minimum in January of 16° C (61° F) to a mean maximum of 31° C (88° F) in August (5). Potential evapotranspiration over the same regions varies between 1400 and 1900 mm (55 and 75 in) annually, with the lowest measurements in the mountainous interior.
Throughout the West Indies, roble is found predominately in areas where the annual rainfall varies between about 1000 and 2500 mm (39 and 98 in) (table 1). All sites are frost free.
Table 1- Presence of roble blanco (Tabebuia heterophylla) in tropical forests of the Western Hemisphere. Islands Forest types¹ Puerto Rico Dry Evergreen Forest Lower Montane Rain Forest Nevis Dry Evergreen Forest St. Kitts Dry Evergreen Forest Dominica Dry Scrub Woodlands Fire grassland and standards St. Lucia Littoral Woodland Dry Scrub Woodlands Secondary Woodlands St. Vincent Dry Scrub Woodlands Grenadines Dry Scrub Woodlands Grenada Dry Scrub Woodlands Antigua Secondary Woodlands Barbuda Bush land Anguilla Bush land Barbados Dry Scrub Woodlands Martinique Seasonal Forests Dry Scrub Woodlands Guadeloupe Dry Scrub Woodlands Littoral Woodland British Virgin Islands Dry Scrub Woodland Xerophytic Rain Fore ¹Roble is found throughout the Windward and Leeward Islands as a component of the Dry Zone Flora with rainfall between 900 to 1700 mm/yr (35 to 65 in/yr). In all instances, classification is according to Beard (1,2,3).
The heartwood is light brown or golden and not easily separated from the sapwood. The grain is straight to interlocked, and the specific gravity is about 0.55. The wood seasons rapidly with little warping and is fairly easy to work, rating fair for planing, excellent for boring, mortising, and sanding, and good for turning. Penetration and absorption of preservatives is low, even in the sapwood (6,16,17,18). The wood is tough and strong for its weight.
Roble's appearance and technical properties resemble both oak and ash. The wood is widely used for flooring, furniture, cabinetwork, interior trim, tool handles, decorative veneers, boatbuilding, ox yokes, millwork, and sporting goods. Less valuable grades are suitable for boxes, crates, concrete forms and similar items, and occasionally for posts and poles (16,17,18).
Roble's large flowers and narrow, columnar crown have made it a favorite ornamental in yards and along roadsides throughout Puerto Rico. Flowering in many instances has been observed a few years after planting (22).
The tree comes in readily on abandoned farm soils and is particularly adapted to degraded sites. Foresters have planted it on abandoned farmlands where its growth has been slow, but satisfactory.
In Puerto Rico, roble is associated with algarrobo (Hymenaea courbaril), laurel avispillo (Nectandra coriacea), guamá (Inga fagifolia), and laurel geo (Ocotea leucoxylon) in the Dry Evergreen Forest (classification according to Beard, 1,2,3). In the Lower Montane Rain Forest of the Luquillo Mountains, it is found associated with guamá, yagrumo macho (Didymopanax morototoni), palo de matos (Ormosia krugii), achiotillo (Alchornea latifolia) and various composites, all of which are constituents of the secondary vegetation (9).
In the Windward and Leeward Islands, roble is frequently found with the same species listed for the Dry Evergreen Forest of Puerto Rico. Beard (2) called this the dry zone flora, of which the Dry Evergreen Forests, Dry Scrub Woodland, and Littoral Woodland are the principal forest types.
In the natural forest, pathogens do not appear to be of any consequence. However, branches of city and roadside trees are often deformed into a witches' broom appearance, apparently by a virus possibly transmitted by the leaf hopper Protalebra tabebuiae (8). The insect also defoliates the tree or causes the leaves to turn yellow and fall prematurely (16,22). A similar disease on a closely related species, Tabebuia pentaphylla, was observed on trees grown for cacao shade on the Paria peninsula of Venezuela (7). Because of the numerous problems with pathogens, some authorities have recommended that closely related members of the same genus be used as substitutes in ornamental plantings.
A dieback disease was observed in 3 percent of potted trees in the Cambalache nursery on the north coast of Puerto Rico and was attributed to Botryodiplodia spp. (13). Transplants from a nearby wooded area to a golf course near the town of Dorado were infested by a shoot borer, probably Pachymorphus subductellus (14).
The heartwood is rated as moderately durable in contact with the ground, but susceptible to Cryptotermes brevis, the dry wood termite (6,29) and marine borers (16). Moreover, the wood rates only fair in weathering characteristics. Unpainted wood loses its smooth surface and develops considerable checking (17).