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Growth and seasonality of seedlings and juveniles of primary species of a cloud forest in northern Venezuela

Published online by Cambridge University Press:  10 July 2009

Saúl Flores
Saúl Flores
Affiliation:
Centro de Ecología y Ciencias Ambientales, Instituto Venezolano de Investigaciones Científicas, I.V.I.C, Apartado 21827, Caracas 1020-A, Venezuela.
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Abstract

The survival, height and leaf production of seedlings and juveniles of Aspidosperma fendleri and Richena grandis were measured monthly for three years after germination. During the first year, some seedlings and juveniles of Aspidosperma fendleri were collected and the number of rootlets, the primary root length and the shoot: root ratio were determined.

Both species show periodicity in growth but their relative growth rate differs between species. For Aspidosperma fendleri, the highest relative growth rate (0.313 y-1) was found for individuals grown under greenhouse conditions followed by individuals growing in an old forest gap (0.143 y-1) and finally individuals under the forest canopy (0.137 y-1). For Richeria grandis, the relative growth rate under the forest canopy was 0.261 y-1. Leaf production for Aspidosperma fendleri in the forest (natural conditions) was 4.39 total mean leaf number for five years and 5.46 total mean leaf number under greenhouse conditions. For Richeria grandis it was 5.34 mean leaf production for four years. The root: shoot ratio for Aspidosperma fendleri was constant during the observation year. Aspidosperma fendleri showed a lower number of rootlets than did Richeria grandis. There was an inverse relationship between growth and survival during the dry season. During this period, mortality was higher and the highest mortality occurred during the first year when the total relative growth rate was highest.

Slow growth is evident in both species. This mechanism may represent an adaptive advantage to remain dormant until there is an opening in the forest canopy. Since the seeds of Aspidosperma fendleri and Richeria grandis are highly vulnerable to predators and pathogens, slow growth as seedlings and juveniles allows them to survive, and contributes to regeneration in cloud forest.

Keywords

Aspidosperma fendlericloud forestgrowthRicheria grandisseasonalityseedlings
Type
Research Article
Information
Journal of Tropical Ecology , Volume 8 , Issue 3 , August 1992 , pp. 299 - 305
Copyright
Copyright © Cambridge University Press 1992

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References

LITERATURE CITED

Brokaw, N. V. L. 1985. Gap-phase regeneration in a tropical forest. Ecology 66:682–687.CrossRefGoogle Scholar
Clark, D. B. 1990. The role of disturbance in the regeneration of neotropical moist forests. In Bana, K. S. & Hadley, M. (eds). Reproductive ecology of tropical forest plants, UNESCO, Paris and Parthenon Publishing, Carnforth. In press.Google Scholar
Connell, J. H. 1978. Diversity in tropical rain forests and coral reefs. Science 199:1302–1310.CrossRefGoogle ScholarPubMed
Cuenca, G. 1976. Balance nutricional de algunas leñosas de dos ecosistemas contrastantes: Bosque nublado y Bosque dcciduo. Trabajo especial de grado, Escuela de Biologia, U.C.V. 120 pp.Google Scholar
Denslow, J. S. 1980. Gap partitioning among tropical rainforest trees. Biotropica 12 (Supplement):47–55.CrossRefGoogle Scholar
Guevara, S. A. A. & Gomez-Pompa, J. 1972. Seed from surface soil in tropical regions of Veracruz, Mexico. Journal of the Arnold Arboretum. 53:312–335.CrossRefGoogle Scholar
Hartshorn, G. S. 1978. Tree falls and tropical forest dynamics. Pp. 617–638 in Tomlinson, T. B. & Zimmerman, M. H. (eds). Tropical trees as living systems. Cambridge University Press, Cambridge.Google Scholar
Hartshorn, G. S. 1980. Neotropical Forest Dynamics. Biotropica 12 (Supplement): 23–30.CrossRefGoogle Scholar
Hunt, R. 1982. Plant growth curves: An introduction to the functional approach to plant growth analysis. Edward Arnold, Garbutt K. American Journal of Botany 73:1364–1371.Google Scholar
Njoku, E. 1963. Seasonal periodicity in the growth and development of some forest trees in Nigeria. Journal of Ecology 51:617–624.CrossRefGoogle Scholar
Odum, H. T. & Pigeon, R. F. (eds). 1970. A tropical rain forest. US Atomic Energy Commission, National Information and Technical Services, Springfield, Virginia.Google Scholar
Pickett, S. T .A. 1983. Differential adaptation of tropical tree species to canopy gaps and role in community dynamics. Tropical Ecology 24:68–84.Google Scholar
Popma, J. & Bongers, F. 1988. The effect of canopy gaps on growth and morphology of seedlings of rain forest species. Oecologia 75:625–632.CrossRefGoogle ScholarPubMed
Ricklefs, R. E. 1977. Environmental heterogeneity and plant species diversity: a hypothesis. American Naturalist 111:376–381.CrossRefGoogle Scholar
Richards, P. W. 1957. The tropical rain forest. Cambridge, University Press, New York.Google Scholar
Sokal, R. R. & Rohlf, F. J. 1969. Biometria. H. Blume Ediciones, Madrid.Google Scholar
Steyermark, J. A. & Huber, O. 1978. Flora del Avila. Sociedad Venezolana de Ciencias Naturales, Caracas. 971 pp.Google Scholar
Whitmore, T. C. 1984. Tropical rain forests of the far east, 2nd edition. Clarendon Press, Oxford. 352 pp.Google Scholar