Assessing Site Productivity Across Age-Class Structured Pinus caribaea Stands, Using Site Index and Growth Variables” in Enugu-Ngwo, Nigeria

Ogu  Comfort Iworima; Oyebade  Bukola Amoo

doi:10.54652/rsf.2026.v56.i1.643

Authors

Ogu Comfort Iworima Ignatius Ajuru University of Education, Port Harcourt, Rivers State, Nigeria.
Oyebade Bukola Amoo Department of Forestry and Wildlife Management, University of Port Harcourt, Choba

DOI:

https://doi.org/10.54652/rsf.2026.v56.i1.643

Keywords:

dominant height, Site index, basal area, Pinus caribaea, plantation productivity

Abstract

Assessing site productivity and growth performance is vital for effective management of plantation forests. This study evaluated growth dynamics and site index variation among three age structured Pinus caribaea stands (49, 50, and 51year-old) in the Enugu-Ngwo Forest Reserve, Nigeria. Data on diameter at breast height (DBH), Height and basal area were collected systematically from 20 × 20 m plots established. Site index (SI), Basal area, Dominant height, provided measures of productivity indicators. Analysis of variance showed significant differences in growth parameters among plots and stands, revealing notable spatial heterogeneity. Site Index values ranged from 0.652 in the 50year stand to 0.729 in the 49year stand, indicating meaningful productivity gradients. The 49-year-old stand exhibited superior diameter, height and basal area, a, showing the stand with highest productivity. Non uniform site quality across the reserve highlighted localized influences of environmental and historical factors. generally, Pinus caribaea plantations demonstrated strong productivity potential, particularly in the 1976 stand, which showed a strong height age trend. The study emphasizes the need for site specific silvicultural practices adaptive rotation planning and continuous monitoring to improve timber yield and sustain long term forest productivity.

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