Influence of silvicultural regimes on woody species density and abundance in Kimondi forest, Nandi county, Kenya

Abstract

Forest ecosystems are increasingly experiencing declines in woody species density and abundance due to inadequate and poorly implemented silvicultural practices. These changes threaten forest structure, biodiversity, and the quality of timber production, particularly in plantation forests where management interventions play a critical role. In Kenya, limited empirical evidence exists on how specific silvicultural regimes such as thinning and pruning influence woody species density and abundance, despite their widespread application in forest management. This study is anchored in ecological theory, which explains how species interactions, resource availability, and disturbances influence the distribution, density, and abundance of species within ecosystems. This theoretical framework provides a basis for understanding how silvicultural practices modify forest structure and species dynamics. This purpose of this study was to to assess the influence of silvicultural regimes on woody species density and abundance in Kimondi forest, Nandi County. The specific objectives were to: Determine the influence of thinning and pruning regimes on the woody species density and abundance in Kimondi forest; assess the influence of thinning on woody species density and abundance in Kimondi forest; and examine the influence of pruning regime on woody species density and abundance in Kimondi forest. The study adopted a cross-sectional descriptive research design. A total of 30 sample plots measuring 20 m × 20 m were selected using purposive sampling. Data collection involved field observation and measurement of woody species abundance and richness. The study focused on three commercially important woody species: Eucalyptus saligna, Pinus patula, and Cupressus lusitanica. Data were analyzed using descriptive statistics, one-way ANOVA, two-way ANOVA, Duncan’s Multiple Range Test. The effect size was calculated using (Eta²) to determine the magnitude of differences among regimes. The results revealed that 36.1% (Eta² = 0.36098) of variation of woody species density and abundance are influenced by combined thinning and pruning regimes. Thinning regime influenced 75.19% (Eta² = 0.7519) variation of woody species density and abundance. Moreover, pruning regimes influenced 61.14% (Eta² = 0.61139), variation of woody species density and abundance. The study demonstrates that applying appropriate, species-specific thinning and pruning regimes enhances woody species density and abundance, thereby improving timber productivity. The study recommends the adoption of species-specific silvicultural regimes tailored to ecological requirements of individual species in order to improve the abundance and density.