Abstract:

This dissertation is structured into three chapters; that is General introduction and two manuscripts. Chapter One describes the background and scope of the study. Chapter Two is titled “Patterns of Specific Leaf area of trees in Mabira Forest Reserve, Uganda”. It contains information on the relationship between SLA and tree height, family, leaf type and leaf area. Specific Leaf Area (SLA) was chosen to this study because it’s direct relationships to plant physiological processes such as photosynthetic rate. Leaves were collected randomly from selected tree species and leaf area was measured. The leaves were oven dried, and SLA is the ratio of Leaf area (LA) and dry leaf weight (DW). SLA varied significantly among trees (P<0.001) and within leaves and leaf types. For instance, there was a significant difference between leaves collected from the Upper, Middle and Lower parts of the crown for 86% of the species in the study. However, the differences did not increase or decrease with crown height. Since SLA has a direct relationship to resource requirements and photosynthetic rates, species with low SLA e.g. Rinorea ardisiifolia, Sterculia dawei and Warburgia ugandensis can be used to restore lowly degraded parts and those with high SLA e.g. Turraea robusta. Vernonia auriculifera and Oncoba spinosa can be used to restore highly degraded parts of the forests Chapter Three is titled “Deriving functional groups for Mabira Forest tree species and predicting their Potential role in forest Restoration”. It presents the functional classification of tree species for Mabira Forest reserve. A functional approach based on 18 morphological traits including Leaf, bark, stem, flower, sex and defense was used to classify 100 tree species into groups of similar ecological function(s). The traits were compiled from literature about flora of Uganda. Leaf area and Specific Leaf Area were determined from collected and
measured leaves as described in Chapter IL Hierarchical cluster analysis with the computer program Genstat was used to generate the groups. Seven functional groups were obtained each represented by 3-39 species. The groups represent species in the various successional stages. I recommend planting the degraded parts with species that are represented in the various functional groups.