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Abstract. Understanding the dynamics of woody tree species distribution in savanna systems remains a challenge despite considerable attention the topic has received in recent years. Disturbances such as fire and elephant effects on woody vegetation are well documented, yet the influence of these factors on emerging landscape-scale patterns such as height and species distributions continue to be poorly understood. The aim of this study was to identify how a suite of environmental variables (rainfall, temperature, aspect, slope, geology, fire frequency and elephant density) and their relative contributions, may affect woody species distribution in relation to structural height classes. Using the Maximum Entropy model for three structural height classes of the fifteen most frequently occurring woody species in the Kruger National Park (South Africa), the environmental variables best explaining each species distribution were identified. The three structural classes were defined to capture canopy height categories of specific management interest, namely Shrub (0.75-2.5 m), Brush (2.5-5.5 m) and Tree (over 5.5 m). The weighted contributions of environmental variables for each species and its associated size class were further analyzed for similarities using a resemblance matrix based on the Bray-Curtis similarity index coupled with a hierarchical clustering test. Our main findings suggest that the patterns and processes driving woody composition and structure are largely decoupled and that the distribution of different structural classes of a particular species may not be driven by the same environmental variables. Future studies should take cognizance of this as ignoring one or the other may lead to confounding results.

The main features of climate and vegetation of the Kruger National Park are discussed. The dry tropical climate induced lush deciduous savannas with a great variety of species and diverse vegetation structures. Variations in species composition and structural features are mainly regulated by soil type and fire regime