A survey to determine the variation in species and structural composition of trees along the edge-interior gradient was done in the Kilengwe forest in Morogoro region, Tanzania. The forest was categorized into three habitats, namely, edge (0–100？m), intermediate (100–200？m), and interior (>200？m) depending on the distance from the forest margin. A total of six plots of 0.04？ha each were randomly placed in each of the habitats whereby all trees with DBH ≥ 10？cm were inventoried. A total of 67 species representing 26 families were recorded. Fabaceae was the most speciose and abundant family. Brachystegia spiciformis was the most abundant species. Of the recorded species, 10.45% were common in the three habitats while 8.95%, 13.43%, and 26.86% occurred exclusively to the edge, intermediate, and interior habitats, respectively. The forest interior was significantly rich in terms of species richness, diversity, density, and basal area than the edge and intermediate habitats. The edge had significantly higher number of stumps/ha. In summary, the results suggest that edge/intermediate and interior are contrasting habitats in terms of tree species richness, diversity, and structural composition. Moreover, the forest edge and intermediate habitats were found to be characterized by high anthropogenic activities compared to the forest interior habitat. 1. Introduction Forest fragmentation and deforestation are among the critical environmental problems with possible implications on a global scale [1, 2] as human activities convert continuous forests into number of patches [3]. The tropical forests that encompass 6% of the world’s land area and harbor at least 50% of the world’s biodiversity are deforested and fragmented at an alarming rate [4, 5]. For instance, the global annual losses of 5.2 × 106？ha/year and 8.3 × 106？ha/year due to fragmentation and deforestation in the tropical forest area were recorded between 1990–2000 and 2000–2010, respectively [6]. In Tanzania, the annual loss of forest cover increased by 37% from the period of 1990–1995 (322,000？ha/year) to 2000–2010 (403,000？ha/year), which was mainly due to increased demand as the population grows [6, 7]. The forest fragmentation process disrupts structure and spatial continuity as it reduces original area, increases edge formation, and isolates remaining forest patches [3, 8]. The formation of edges is recognized to be fundamental of ecological change as it involves alteration of microclimatic conditions, enhances invasion by exotic species, and increases the human pressure [9, 10]. Due to this,
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