Changes in Leaf Morphology and Foliar Nutrient Status Along a Successional Gradient in a Costa Rican Upper Montane Quercus Forest

Abstract

Morphology and mineral levels of leaves of 19 secondary and 22 primary tree species were studied in Quercusdominated upper montane 10-year-old Early Secondary Forest (ESF), 30-year-old Late Secondary Forest (LSF) and undisturbed Primary Forest (PF) in the Costa Rican Cordillera de Talamanca. In general, the predominant leaf is simple, elliptic, entire, and pinnately veined. Notophyllous and microphyllous-sized leaves dominate all spectra. During secondary succession the mean leaf area of secondary species tends to reduce 30 to 65 percent, while the average leaf area of primary species doubles. Primary species exhibit a greater mean leaf dry weight per unit area than secondary species. As succession proceeds, the mean leaf water content drops among secondary species and rises among primary species. During forest recovery levels of foliar nitrogen, phosphorus, and potassium decline significantly. In leaves of species in ESF nitrogen, phosphorus, and potassium are significantly correlated. Values for leaf characteristics recorded in Costa Rican montane ESF, LSF, and PF fall mainly within the ranges known from other tropical montane forests.