Tese
Variações espaço-temporais no crescimento de Dalbergia nigra (Vell.) Allemão ex Benth
Fecha
2014-07-31Autor
Vanessa Pontara
Institución
Resumen
Spatio-temporal variation in soil resource availability associated with topography and
seasonality may drive patterns of tree growth and phenology, but these links are poorly
characterized for most tropical tree species. We use dendroecological methods to test the
hypothesis that variation in topographic position is related to radial growth and phenology
for individuals of the endangered tropical tree Dalbergia nigra under uniform conditions of
climate and irradiance, and to examine effects of seasonality on plant phenology and
growth periodicity. Dendrometer-based measurements of stem diameter change over 26
months and local measurements of soil nutrient and water availability were compared for
24 individuals of D. nigra distributed equally between summit and valley positions within
a topographically heterogeneous fragment of Atlantic rain forest in southeast Brazil. Soil
water and nutrient availability, and cumulative radial growth, were greater for trees in
valley than summit positions. Monthly diameter increment was seasonal and positively
related to monthly rainfall. D. nigra was seasonal in all phenophases, regardless of
topographic position, and there were no differences in the frequency, timing or intensity of
phenophases among topographic positions. We conclude that low soil nutrient and/or
moisture availability reduce radial growth of D. nigra individuals growing in summit
positions, while trees growing in valleys exhibit faster annual growth, but that vegetative
or reproductive phenology are unaffected by fine-scale variation in topography.