Defoliation, Recovery and Increasing Mortality in Italian Forests: Levels, Patterns and Possible Consequences for Forest Multifunctionality

Forest health and multifunctionality are threatened by global challenges such as climate change. is currently assessed within the pan-European ICP Forests (International Co-operative Programme on Assessment Monitoring of Air Pollution Effects Forests) programme through evaluation tree crown conditions (defoliation). This paper analyses results a 24-year assessment carried out in Italy 253 permanent plots distributed across whole forested area. The evidenced substantial stability at national level, according to usual defoliation thresholds Defoliation > 25% 60%, albeit with species-specific patterns. Within this apparent temporal stability, an increased fraction extremely defoliated dead trees was observed. Extreme mostly occurred years severe summer drought, whereas mortality higher after drought. for singular species critical Castanea sativa Mill. Pinus species, Quercus showed progressive decrease defoliation. Deciduous Fagus sylvatica L., Ostrya carpinifolia Scop. pubescens Willd. suffer loss leaves dry strategy limit water transpiration but recover their following years. recurrence extreme heat waves drought from beginning XXI century may increase vulnerability forests, can be expected future.