EN
The structure of epicuticular wax on the stomata surface in both very young and one-year-old fir needles from Risnjak National Park in Croatia were examined with a scanning electron microscope. The stomata surface is first covered with wax crystalloids in the form of rodlets. In the course of time the rodlets become fused and agglomerated into amorphous wax crusts; this process begins very early. In addition to wax crystalloid quantitative estimation indicates a relatively large total amount of amorphous wax in very young needles (~20 days) and a very high percentage of amorphous wax crusts in one-year-old needles. Wax crusts cover stomatal pores in addition to the rims, making normal gas exchange impossible. The early start of wax degradation may be interpreted as a possible result of air pollution.