Structure, Species Composition and Status of Naturally Regenerated Woody Species in Eucalyptus globulus Labill. (Myrtaceae) Plantation at Entoto Mountain, Ethiopia

Abstract

This study was carried out at Entoto Mountain Eucalyptus plantation; about 10 km north of the center of Addis Ababa, to assess the composition, structure and the status of naturally regenerated woody species in Eucalyptus globulus Labill. plantation. Sixty plots of 400 m ² (20 m X 20 m) size were established along a transect lines at every 300 m distance between them. Transects were laid in north–south directions at 500 m distance from each other. Seedlings were colleted from five sub-plots (4 m ²) within each major plot. A total of 41 naturally regenerated woody species (NRWS) were recorded in Entoto E. globulus plantation. They represented 33 genera and 25 families. Density of NRWS greater than 2.5 cm DBH was 932.1ha^-1. With increase in diameter class, the number of NRWS decreased in the E. globulus plantation. About 87% of the individuals had DBH of first DBH class (2.6-7.5 cm). Density ratio of individuals >10 cm DBH to that of individuals >20 cm DBH showed the predominance of small-sized individuals; this is the result of the recent regeneration. The ratio of stems per species is very high in the lower storey (63.9) also showed the predominance of shorter high individuals. J. procera (98.3%) was the most frequent NRWS and had an overriding dominance in terms of basal area (95.16%) and IVI values (81.8%). This result may indicate that J. procera is eco-friendly and competent with E. globulus. Therefore, E. globulus may not have a negative effect on J. procera. Thus, in degraded high rainfall areas, E. globulus plantations may play a role in fostering the regeneration of woody species such as J. procera. Species were prioritized for conservation using important value index, population structure and regeneration status as criteria.

Keywords: Entoto, Eucalyptus globulus, naturally regenerated woody species, Plantation