The Influence of Different Land Use on the Morphology and Seed Characteristics of Gmelina arborea in Nasarawa State, Nigeria

This study evaluated the influence of various land use types on the morphological traits and seed characteristics of Gmelina arborea across four locations in Nasarawa State, Nigeria: Akwanga, Doma, Lafia, and Nasarawa Eggon. Significant variation in tree morphology was observed relative to land use, with conserved, residential, and recreational areas consistently supporting more robust growth. For instance, in Akwanga, trees in residential areas exhibited the greatest height (16.81 m) and crown area (687.38 m²), while conserved sites recorded the highest tree volume (61.52 m³). Similarly, in Doma, recreational sites had the tallest trees (14.93 m), largest crown areas (393.82 m²), and highest tree volume (123.96 m³). Lafia recorded the highest overall tree volume (70.78 m³), particularly within conserved areas (439.46 m³), with Nasarawa Eggon also showing significant growth differences among land uses. Tree morphometric parameters such as diameter at breast height (DBH), bole height, and tree slenderness varied markedly among land uses, reflecting the impact of anthropogenic disturbance on tree architecture. Seed morphometric traits also differed significantly by land use type. In Akwanga, seeds from recreational and hospital areas produced the heaviest pods (3.42 g) and longest pod lengths (2.63 cm), while conserved areas yielded the heaviest seeds (1.27 g). At Doma, the recreational site similarly produced the longest pods (2.73 cm) and heaviest seeds (1.23 g). Seed texture varied with rough textures observed mainly in mechanic and office areas, and seed color differences ranged between brown and black varieties across sites. The study concludes by showing that the kind of land use has a substantial impact on the morphological qualities and seed properties of Gmelina arborea in all four locations in Nasarawa State. Reduced anthropogenic disturbance improves tree vigor, as evidenced by the higher growth performance of trees growing in residential, recreational, and conservation environments in terms of height, crown development, and volume. Seed quality and potential regeneration capacity may also be impacted by environmental factors and human activity, according to differences in seed morphometric features among land use types.