Annual rainfall, topoedaphic heterogeneity and growth of an arid land tree (Prosopis glandulosa)

Basal area growth rates for Prosopis glandulosa were quantified for contrasting landscape elements in a subtropical savanna. We hypothesized that growth rates of P. glandulosa plants (1) are a function of seasonal or annual rainfall; and (2) vary with patch type and in the rank order observed for large trees. Prosopis glandulosa growth was responsive to changes in rainfall (-0.974 cm² year^-1 in a dry year; 9.108 in a wet year), but correlations with rainfall were low. Growth of trees in contrasting patches was not consistently different, suggesting that contrasts in tree sizes across the landscape reflect differences in establishment dates rather than differences in growth rates.