Abstract

This study characterizes the floristic and structural traits of trees in three sites of rainforest of Cameroon. The sites were exposed to different intensities of disturbances: Mangombe, highly and frequently disturbed; Bidou, moderately disturbed and Campo, undisturbed. Data collection were carried in a disposive comprising 65 plots of 20 m × 20 m randomly installed in each site for inventory, identification and measurement of diameter of trees greather than 10 cm at 1.30 m height. In total, 4717 plants belonging to 130 species and 43 families were recorded in all the sites. Basal area showed a declining trend with the increase in disturbance intensity while tree density, species richness and families increase with disturbances: Campo (87 m²/ha, 569 trees/ha, 75 species and 29 families); Bidou (54, 538, 88 and 32); Mangombe (49, 708, 91 and 38). The vegetation indices showed a high diversity in all the sites. The Shannon index (5.40 to 5.52) and generic diversity (1.10 to 1.16) had greater value. According to the sample, the floristic composition of Mangombe considerably differs from those of Bidou and Campo. The undisturbed site (Campo) contained young tree population showing a vigorous regeneration while in the highly disturbed site (Mangombe), tree density was scarce, with few big size trees having high cultural importance and low economic value. Low shrub density was recorded in Mangombe and Bidou due to frequent human disturbances. Canopy gaps favor direct sunlight which enhanced the abundance of Shrub in all the sites. More protection is needed for the restoration in the long term of forest cover in Mangombe, which can be done naturally due to high density of small trees composed of species generally found in the upper strata.

Key words: Cameroon, dense humid forest, disturbance, species richness, structure of population.