Forest Structure and Climate Change Mitigation Potential: A Case of Wilolesi and Ikonongo Forested Hills in Iringa Municipality, Tanzania

Vegetation plays major roles in carbon storage and ecosystem functioning by modifying the rate of carbon fluxes thereby mitigating climate change. However, the focus of assessing the potentials for different vegetation on climate change mitigation has for so long been conducted outside cities, towns and municipalities. This study was conducted in Wilolesi and Ikonongo hills located in Iringa as representative of the Municipality forested hills in Tanzania to assess vegetation structure and their potential for climate change mitigation. Random sampling technique was employed to establish 20 rectangular plots of 20 m x 40 m (0.08 ha) in each hill to determine plant species composition, richness, diversity, vegetation structure and above ground carbon (AGC). R-statistical software was used to compute Shannon-Wiener diversity indices, species richness and the above ground carbon. Results indicated high species diversity ranging from 3.5 to 4.1 for Ikonongo and Willolesi hills, respectively based on Shannon-Wiener diversity index (H’). We recorded 255 plant species (114 tree species, 51 shrub species, 2 sedge species, 66 herb species, 15 grass species and 7 climbers) in 60 families. Based on Important Value Index (IVI), Brachystegia spiciformis Benth (10.435) and Julbernardia globiflora Benth (4.555) were important species in Wilolesi and Ikonongo forested hills. There was a significant difference on the AGC between Ikonongo (3.12 t/ha) and Wilolesi (8.33 t/ha) (t = 1.83, p = < 0.004). Results have an implication for dedicating more efforts on the management of forest landscapes for biodiversity conservation, climate change mitigation and provision of other ecosystem services. It is recommended that there should be detailed study for all forested hills in Iringa Municipality for proper forest management initiatives. Keywords: Climate change mitigation potential; forest structure; forested hill