Demography and Production of Balaka microcarpa Burret (Arecaceae), a Tropical Understorey Palm in Fiji

Abstract

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.