Department of Environmental and Geographical Science
Abstract
Bibliography: leaves 92-96.The objective of the present study was to investigate mist interception by Mountain Fynbos under non-rainfall conditions. Quantitative measurements and qualitative observations of plant-drip and stem-flow from selected plant species were recorded at five experimental sites on the Back Table of Table Mountain, Cape Province. Plant-drip and stem-flow catching devices were designed and installed in order to collect the moisture intercepted by plants. The results indicated that mist interception by the vegetation was influenced by wind speed, density of mist and by the morphological characteristics of the plants. Greater interception occurred when dense mist was accompanied by high wind speeds. The interception ability was found to increase with plant size. Interception efficiency depended on the leaf morphology of the plants. Narrow-sclerophylls (e.g. Psoralea pinnata) were found to be more effective in intercepting mist droplets than broad-clerophylls (e.g. Leucadendron salignum). The portioning of intercepted water into plant-drip and stem-flow was largely influenced by the shape of the plant. The mean rate of water yield per plant observed during five periods of rainfree, misty conditions, was 71 ml hr-1 . Rainfall is, therefore, not the sole source of moisture contributing to the water balance. The additional moisture intercepted by vegetation should, therefore, be taken into consideration in studies of water balance and hydrology
