Thesis (PhD (Forest and Wood Science))—University of Stellenbosch, 2006. / Experiments carried out in this study sought to contribute to the understanding of the ecological interactions involved in Uapaca kirkiana seedling establishment and growth in a natural woodland ecosystem. These include soil pH reactions, plant root surface pH change, root exudates that affect the chemical behaviour of the soil in the vicinity of the root, and microbial effects. Although it was difficult to determine which of these factors play a dominant role in the soil-plant relationship, the study contributed to the understanding of the mycorrhizal fungi-host plant association. It revealed the diversity of mycorrhizal fungal species occurring in the different ecological sites, and also analysed the relationship between soil factors. Soil pH and K had significant influences on the fungi population diversity. K was considered important in its role in the translocation of auxins to the root sites where they enhance root susceptibility to mycorrhizal fungal infection. More work needs to be undertaken to establish the role of soil pH.