Monitoring adaptation and productivity of teak plantations in the Guinean Zone of Togo: A comparative study of historical and newly introduced provenances

Teak (Tectona grandis), introduced to Togo in 1905, remains the main species for reforestation. However, the low productivity and poor wood quality of existing plantations, largely due to limited genetic diversity, have prompted the establishment of provenance trials at the Zogbépimé forest station in Togo. This study evaluated the growth performance of seven teak provenances (Avétonou, Indian, Tanzanian, Ivorian, and three Malaysian sources: Luasong, Perlis, and Taliwas) planted in a 3 × 3 m grid in the Guinean zone. Dendrometric parameters including total height, dominant height, diameter at breast height, basal area, and spacing factors were measured. ANOVA and Weibull distribution modelling, were used to assess growth differences and diameter structures. Productivity was estimated using a site index based on dominant height and stand age. Monitoring in 2022 (pre-thinning) and 2024 (post-thinning) showed that the Indian provenance had the best overall performance, with mean diameter increasing from 12.87 ± 3.85 cm to 17.91 ± 2.51 cm. Luasong exhibited superior height growth (16.85 ± 2.88 m) and high basal area (18.94 ± 0.13 m²/ha), while Tanzanian provenance reached the highest basal area (22.27 ± 0.14 m²/ha) and responded strongly to thinning. Avétonou maintained a large diameter (17.22 ± 2.92 cm) but lower height growth. Luasong achieved the highest site index (44.28), followed by Tanzanian and Indian provenances.The study emphasizes the importance of selecting high-performing provenances and implementing timely thinning to minimize competition and enhance resource utilization. Further research will assess the influence of wood quality and site on provenance performance.