Forest Resistance to Insects and Pathogens

Forests provide biodiversity to the planet and other forest ecosystem services – the es-sential benefits of humans from forests. The resilience of forest ecosystems and individual trees to stressors has always interested scientists and practitioners. Scientists have fo-cused on the mechanisms of tree resistance. Practitioners have sought ways to reduce forest productivity losses. This work aimed to review the modern knowledge regarding forest ecosystem resilience, forest health, tree resistance, mutual adaptations of plants and phytophagous insects, and breeding trees for disease resistance. As a case study, the resistance of European ash (Fraxinus excelsior L.) to ash dieback and emerald ash borer Agrilus planipennis Fairmaire, 1888 (Coleoptera: Buprestidae): mechanisms, evidence, and future perspectives is presented. Breeding tree species for resistance to pests should play an important role in preventing their spread. Since each tree species is susceptible to some pests and resistant to others, to ensure maximum resilience, it is advisable to create mixed-age and multi-species stands, despite potential productivity losses.