Taxonomic name:Tabebuia heterophylla (DC.) Britt. Synonyms:Bignonia pallida Lindl. , Tabebuia heterophylla ssp. pallida auct. non (Miers) Stehlé , Tabebuia lucida Britt. , Tabebuia pallida sensu Liogier & Martorell , Tabebuia pentaphylla (DC.) Hemsl. , Tabebuia triphylla DC. Common names: calice du paperpape, pink manjack, pink tecoma, pink trumpet-tree, roble (Spanish), roble blanco (Spanish), white cedar, white-cedar, whitewood Organism type: tree
Tabebuia heterophylla is a small to medium sized deciduous tree attaining a height of 18m. In its native range it is widespread in abandoned pastures and secondary forests. It has become a problem in Pacific regions and is particularly common in dry, coastal woodlands and in secondary forests. It grows on any soil type and will adapt to poor or degraded soils. T. heterophylla regenerates and forms pure monotypic stands. It is an extremely fast growing species and can easily outcompete native and other exotic trees. It bears leaves and branches almost to the base and casts a deep shade under which virtualy no other species can grow. Its thick litter layer may also prevent the growth of native seedlings.
Description T. heterophylla is a small- to medium-size tree attaining a height of 18m and a diameter of 60cm. It has a furrowed bark, and a narrow, columnar crown, with opposite, palmately compound leaves. There are 3-5 leaflets, with blades elliptic to oblanceolate or obovate, 6-16cm long, leathery, acute to blunt at the tip, acute to rounded or oblique at the base; surfaces glabrous; margins entire; petiole 3-12cm long. The flowers are large white to light purple perfect flowers that are borne few to several in terminal and lateral clusters, or occasionally as individuals. The mature fruits are dark brown cigar-like pods, about 8 to 20cm long and 6.5mm in diameter and contain many winged seeds each about 2cm long (Weaver, 1990; PIER, 2004)..
Habitat description Weaver (1990) describes the habitat in which T. heterophylla occurs in Puerto Rico and elsewhere in the caribbean. The author states that states that, in Puerto Rico, T. heterophylla 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. T. heterophylla appers to be tolerant of degraded sites and abandoned farm lands where it tends to form nearly pure stands. It is found growing well on a wide range of soil types but seems to prefer deep clays. In Puerto Rico, T. heterophylla is found on sand, limestone, and heavy clay soils, acid or alkaline in reaction, and residual, alluvial, or colluvial in origin. It is most common on slopes and ridges but is also found on flats adjacent to riverbeds. Elsewhere in the Caribbean, T. heterophylla is particularly common in dry, coastal woodlands and in secondary forests. It grows on any soil type and will adapt to poor or degraded soils if moisture is available.
General impacts On the island Mauritius, Parnell et al. (1989) found that, "T. heterophylla was spreading rapidly on the island, with small numbers of mature trees present but abundant young plants and seedlings. It appears to grow faster than any native or exotic tree on the island. Most T. heterophylla bear leaves and branches almost to the base and cast a deep shade under which virtually no other species grow. T. heterophylla is deciduous and its thick litter layer may also prevent the growth of native seedlings. PIER (2004) states that, "T. heterophylla is invasive in Hawai‘i. It is also reported invasive on Diego Garcia and naturalizing on Kwajalein (Whistler and Steele, 1999). T. heterophylla is also naturalized in some locations on Nimitz Hill, Guam (Bart Lawrence, personal communication)." Zimmerman et al. (2000) state that, "T. heterophylla readily invades pasture via seed." In their study, Zimmerman et al. (2000) state that, "T. heterophylla appears to facilitate the colonization of many common forest species that are unable to establish in recently abandoned pasture." Weaver (1990) states that, "T. heterophylla regenerates and forms pure stands on grasslands and degraded soils, in particular on exposed upper slopes and ridges, where competition from faster growing, larger, and more tolerant trees is lacking." In the seedling and sapling stages, T. heterophylla is an aggressive pioneer (Weaver, 1990), and it can maintain viable populations in both dry and moist forest habitats (Cordero and Molano, 1996).
Uses Weaver (1990) states that, "In Puerto Rico, T. heterophylla 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. It has also done well on humid, waterlogged sites." Weaver (1990) states that, "T. heterophylla'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. T. heterophylla's large flowers and narrow, columnar crown have made it a favourite ornamental in yards and along roadsides throughout Puerto Rico. Flowering in many instances has been observed a few years after planting." Showler et al. (2002) discovered that Rodrigues Warblers (Acrocepbalus rodericanus) were also found in plantations dominated by T. heterophylla but at much lower densities than is typical for the species.
Geographical range Native range: South America (USDA-NRCS, 2004) Known introduced range: Australasia-Pacific (PIER, 2006)
Local dispersal methods On animals (local): Zimmerman et al. (2000) report that T. heterophylla is a wind-dispersed species.
Reproduction Zimmerman et al. (2000) report that T. heterophylla is a wind-dispersed species.
Lifecycle stages In Puerto Rico, flowering is chiefly in the spring, or dry season, and is accompanied by complete leaf drop. Sporadic flowering occurs at other times. Fruits are borne in May and June with fruit fall varying from July through September., and may be found on the tree during most of the year (Weaver, 1990). Weaver (1990) states that “T. heterophylla's seed capsule splits along two lines and seeds are dispersed varying distances from the parent tree, ranging up to 100m or more, depending upon weather conditions. The seeds germinate in open areas and form dense stands of seedlings.” The author states that, "Several seed experiments were conducted at the Institute of Tropical Forestry during the mid-1940's. About 70,000 air-dried seeds were counted per kilogram (31,750/lb), and these had mean moisture content of 31 percent, based on the dry weight of the seeds. Seeds sown directly in seedbeds after collection in the field showed germination rates of 90 percent within 2 weeks. A 3-week delay in sowing seeds reduced viability to about 55 percent and after 5 weeks, no seeds germinated. Attempts were made to store seeds for long periods using seed moisture contents of 100, 75, 50, and 25 percent at room temperature and at 4' C (40' F). The best germination after 25 months, nearly 55 percent, was attained with the lowest moisture content and temperature combination."
