Relationships between transpiration, stomatal damage and leaf wettability in declining beech trees

In 50 declining beech trees growing in Pian di Novello, Italy, the relationships between transpiration, stomatal condition, and leaf wettability were determined. The analytical procedures used are detailed. Results showed that the transpiration of declining trees was not always lower than healthy trees, due to humidity effects. Structural damage to the stomata showed no significant difference between healthy and declining trees in June, but the damage was markedly worse in declining trees in September. The drop contact angle on leaves from declining trees was significantly higher in June than it was on leaves from healthy trees and was much lower in September in declining trees, while no difference was observed in healthy trees. No important relationships between the three parameters were discerned.