Abstract

PARRA ALDANA, César Augusto; DIEZ GOMEZ, María Claudia  and  MORENO HURTADO, Flavio Humberto. Natural Regeneration of Black Oak (Colombobalanus excelsa, Fagaceae) in Two Populations from the Cordillera Oriental of the Colombian Andes. Rev. Fac. Nac. Agron. Medellín [online]. 2011, vol.64, n.2, pp.6175-6189. ISSN 0304-2847.

Colombobalanus excelsa is an endemic species of the Andean region of Colombia, with four isolated populations, forming pure stands called black oak forests. It has been classified in the threat category "Vulnerable", mainly due to conversion of forest to agricultural uses; in addition, field observations indicate that natural regeneration under its own canopy is scarce. In this paper we intend to answer the following two questions: i) ¿Does the forest structure show evidence of deficiencies in the natural regeneration of two populations of black oak located in the eastern cordillera of Colombian Andes? ii) ¿Is the recruitment of fhmoreno@unal.edu.co limited by the availability and viability of seeds in both populations studied? For this purpose, 16 0.1 ha permanent transects were established to evaluate the structure of adults (DBH>10 cm) and natural regeneration. One year monitoring was performed on fruiting times, seed rain, germination, and seed bank. Results show an extremely low supply of seedlings and propagules of black oak, which can potentially endanger the persistence of these forests. This situation is due to various factors involved in the regeneration process: from low seed production of mature trees, high levels of pre-dispersal predation, high proportion of empty seeds, low viability of healthy seeds, to high mortality of the healthy and viable seeds that reach the ground. While all these factors act in cascade, the last one could have the most dramatic effect in the low reproductive success of this species.

Keywords : Andean forests; fruiting; sexual reproduction; Trigonobalanoideae.

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