IMPACT OF SELECTIVE TIMBER HARVESTING ON RESIDUAL TREE SPECIES IN A HUMID LOWLAND RAIN FOREST OF SOUTHWEST NIGERIA

Abstract

This study assessed the impact of selective timber harvesting on residual trees in a natural forest in southwest Nigeria. Damaged residual trees were identified and their volumes estimated, while level of damage and compliance of logging operators to reduced impact logging were evaluated. Fourteen sample plots were randomly laid in a 40ha forest concession and then height and diameter at breast height (dbh) of harvested and damaged residual trees were enumerated. An integrated stem damage code was used to ascertain the type and level of tree damage. Interviews were used to elicit information on socioeconomic characteristics of 42 operators, causes of damage and precautions taken to mitigate tree damage.

Twenty-one species (42 tree ha^-1) were harvested, while 28 residual tree species (74 trees ha^-1) were damaged. Sterculiaceae (14.3%), and Moraceae (10.7%) had the highest representation among the damaged trees. Mean height and dbh of damaged residual trees were 8.84 ± 0.55 m and 76.31 ± 3.60 cm, respectively. Most trees were sseverely damaged (60%) due to complete uprooting, crown breakage and canopy loss. Most logging operators (92.9%) lacked formal training in harvesting operations and sustainable management principles (83.3%). Therefore, capacity building and in reduced impact logging is required to ensure site protection and sustainable management.

Keywords: reduced impact logging - stem damage - timber concession - bole-breakage