Comparative analysis of population structure, vegetation composition and soil properties across selected wild loquat (uapaca kirkiana) populations in Northern Malawi

Abstract

Uapaca kirkiana is an important indigenous fruit tree species whose population is declining in its natural habitat. Its fruits contribute to food security and serve as a source of income. Little is known about its ecological status in northern forests of Malawi. This research comparatively investigated the population structure, species associations, and soil preferences of U. kirkiana between Perekezi and Kaning’ina forest reserves. Fifty circular plots of 40 m diameter were established, and diameter at breast height (DBH) ≥5 cm were measured, while juveniles (<5) were counted to assess recruitment. Independent t-tests were used in comparison when assessing the population structure, species richness and soil properties. Diameter structures were further described through gamma distribution fitting. The data were analyzed using R v4.2.2 statistical software. Both sites showed an inverted J-shaped diameter distribution, although Kaning’ina contained more mature trees with a mean DBH of 20.58 cm, compared to Perekezi’s 11.42 cm. Significant differences appeared in height, crown diameter and slenderness coefficient. Higher proportion of unhealthy U. kirkiana trees observed at Kaning’ina. Brachystegia spiciformis and Faurea rochetiana were among the species closely associated with U. kirkiana at both sites. Perekezi’s soils were classified as loamy sand, showing a significantly higher sand content (79.80 ± 3.89%) and notably lower clay (5.90 ± 2.00%). Kaning’ina was characterized by sandy loam, with slightly less sand (76.60 ± 5.10%) and a higher clay content (8.47 ± 3.39%). Organic content was relatively similar in both reserves. It’s concluded that Kaning’ina forest has U. kirkiana trees with larger DBH than Perekezi while sharing similar species in association with U. kirkiana. The two sites differ significantly in soil texture but organic matter content was not significantly different between them. The study recommends implementing long-term population monitoring, prioritising interventions that enhance regeneration and strengthening site-specific habitat management plans.