Morphological adaptations to climate in six tree species from montane forests in Costa Rica

The acclimatization to two light regimes of the leaves of six species of trees from Costa Rican montane forest was investigated. Seedlings and saplings of the selected species were chosen from prior to the expansion of the foliar lamina to complete development. Groups of specimens previously growing on light were subjected to shade, whilst plants previously shaded were exposed to light. Other did not undergo a change of light regime and were used as ''light controls'' and ''shade controls''. The morphological characteristics evaluated were: foliar area, lamina thickness, stomatal density, specific density, specific leaf weight and specific leaf water content. The observed responses suggest that Quercus copeyensis and Drimys winteri have a greater responses potential for acclimatization to shade whilst Schefflera rodriguesiana acclimatizes better to brighter conditions. Vaccinium consanguineum, Weinmannia pinnata and Quercus costaricensis have the ability to acclimatize to both regimes.