THE IMPACT OF ASPECT ON FOREST FLOOR CHARACTERISTICS IN SOME EASTERN AUSTRALIAN SITES

At upslope positions on steep ridges near the escarpment of northeastern New South Wales, aspect exerts a major influence on the form and functioning of the floors of mature forests. In comparisons of northwest and southeast facing sites, significantly lower concentrations of total N, total P, exchangeable Ca and cation exchange percentage saturation were found in soils of northwest aspects. In similar comparisons of northeast and southwest facing slopes, lower concentrations of soil organic carbon and soil total N were found on southwest aspects. Potential nitrogen mineralisation rates were generally lowest at northwest aspects, a probable indication that the proportion of resistant humic substances in these soils was higher than at other sites. The impact of aspect, mediated through differences in energy inputs, must be considered not only in relation to the current biotic expression of the site, but also in the context of developmental processes. Such developmental and functional differences are of significance to managers of forest resources.