Balaka microcarpa
Balaka (bah-LAHK-ah) microcarpa (migh-kroh-KAHRP-ah) | |||||||
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Hawaii. Photo by Timothy Brian. | |||||||
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Contents
Habitat and Distribution
Fiji. The known range of this palm is very small, occurring immediately north of Suva, Viti levu, only in the forests of Coloisuva and Savura Creek. This species of Balaka grows as an understorey, rarely semi-emergent palm of the wet forests of Coloisuva and Savura Creek at an altitude of 50-300m with an annual rainfall in excess of 4000mm and with no dry season. In the early 1980s, Dr Julian Ash of the University of the South Pacific made a detailed ecological study of this palm over a three year period and found it to be very slow growing with palms maturing at about 5 m in height when they would be about 45 years old. Flowering and fruiting occurs throughout the year. The oldest palm he observed was estimated to be 85 years old. Annual fruit set is very variable with about 180 fruits on each inflorescence each year. Only about 0.1% of these fruit survive to become a mature palm. No observations were made on seed dispersers and so gravity and water are believed to be the main agents. (naturefiji.org)Description
This species of Balaka is usually a small palm, but it can grow up to 13m in height, with an 8 cm diameter trunk. The trunk is green with distinct nodes below the crown shaft, but lower down along the trunk it becomes grey-brown, and is usually heavily adorned with epiphytes, moss and lichen of various colours. It has a compact crown with 7-10 ascending fronds that are up to 2 m in length, with large, well spaced dark green leaflets. As with several, if not all the Balaka, the fronds are considerably longer in those palms growing in full shade than those in open areas. The crown shaft is slight and dark green with inflorescences emerging beneath it. The inflorescences are two or three times branched with a long petiole and are often held erect. The fruit are small, oval in shape; about 2 cm long by 1 cm wide, and are bright orange-red when mature. Young palms are conspicuous, with characteristic entire leaves, the transition from the entire leaf to the pinnate form occurs on average after the 28th leaf. (naturefiji.org) Editing by edric.
To 15 m tall. Stem to 8 cm diam. Leaves 5–10, ascending-arching, slightly recurved, stiffly ascending in open areas with higher light, 1.6–2.2 m long; sheath 30–40 cm long, sometimes dark colored; petiole lacking or to 5 cm long (Fig. 20); blade to 1.2–1.8 m long; pinnae 9–16 per side, elongate-sigmoid, margins converging toward base and apex and there obliquely truncate and toothed, to 55 cm long, to 11 cm wide, thickleathery, distinctly forward-pointing, midrib prominent adaxially. Inflorescences 2 or 3 per plant, infrafoliar, 60–85 cm long, 2– or 3- branched; peduncle to 30–35 cm long; rachis 15–20 cm long; up to 25 rachillae, these 12–30 cm long, spreading; triads nearly to apex of rachilla. Staminate flowers with 20–30 stamens, pistillode ca. equaling stamens or exceeding them, thick, stubby, flexuous. Fruit 1.4–2.0 × 0.7–1.0 cm, ovoid, bright red; fruiting perianth 5 mm long; endocarp 1.3–1.8 × 0.6– 0.9 cm, with 4, prominent, sharp longitudinal ridges and very short rostrum 3 mm long. (iucn.org)
Notes: The ascending to arching leaves with short petioles, elongate, thick-leathery, strongly forward-pointing, obscurely nerved pinnae, and small fruits distinguish Balaka microcarpa. Seedlings and small, juvenile plants have handsome, simple, bifid leaves until they attain about a meter in overall height and have a short stem about 30 cm tall. The unusually short petioles and stiffly ascending leaves trap and collect falling litter from the forest canopy, channeling it into the center of the plant. In disturbed areas where the forest is more open or in areas with a naturally low canopy, Balaka microcarpa is an emergent species and its leaves are frequently stiffly ascending. In these instances, the stiffly ascending leaves and thick-leathery, forward-pointing pinnae immediately conjure up images of a New Caledonia Basselinia pancheri or B. gracilis. (iucn.org)
Culture
Comments and Curiosities
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Conservation: Nearly the entire population is located in one of several adjacent reserves the Coloisuva Forest Park (wholly a mahogany plantation), the Savura Forest Reserve (about 75% mahogany plantations), the Vago Forest Reserve (mature forest) and the Tamavua and Savura Watercatchment Reserve (mature forest). However, about half of this distribution is under planted mahogany (Coloisuva and Savura Forest Reserve). Clearly the felling of the mahogany which has commenced will have a major impact on this palm unless it is undertaken with great care everywhere and the major palm locations are left intact. The current threat category is Endangered (IUCN Global Status) but in view of the on-going felling of the mahogany, and clearance for agriculture elsewhere, this should be revised to Critically Endangered. (naturefiji.org) A population of the understorey forest palm Balaka microcarpa Burret (Arecaceae) was studied in its natural habitat in south-eastern Viti Levu, Fiji. The palm has a juvenile stage with entire leaves followed by a stage in which an aerial stem develops, up to a height of 13 m, and pinnate leaves are produced, which leave distinct scars on the stem. In juveniles, successive leaf lengths increase by c. 1-4 cm and about 28 juvenile leaves are produced. Annual leaf production increased from c. 1.2 year -1 in juveniles to c. 2.2 year-1 in tall palms. The duration of the juvenile phase was estimated as 15-25 years, while the oldest palm observed was about 85 years. Flowering commenced at 5 m stem height, after 40-60 years, with one inflorescence in each leaf axil and 183± 92 (s.d.) fruits on each infructescence. Mortality was estimated as 99.8-99.9% from the seed to juvenile stage, and 1.4-4% year-1 in later stages. A mean generation time of 68 years was calculated. About 23% of net production was used in reproduction during the reproductive period, or about 13% of total net production of an old palm. The demographic characteristics are contrasted with those of other palm species from a variety of habitats. (Demography and Production of Balaka microcarpa, a Tropical Understorey Palm in Fiji By Dr. Julian Ash) |
External Links
References
Phonetic spelling of Latin names by edric.
Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.
Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.
Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.