Global change-related variables are having an increasing impact on forests and plants worldwide. Increased global commerce has made it easier for many insects and diseases to spread to new areas. Numerous of these incursions have resulted in significant forest destruction, negative economic effects, and losses of the ecological services and products that trees supply. The geographic distribution of host trees and the insects and diseases that are linked to them is already being impacted by climate change, and both native and invasive pests are expected to have an increased influence. Many forest insects would benefit from climate change, although phonological mismatches and disruptions to developed life cycle features may result from changes in temperature circumstances. Invasive pests and climate change both represent significant risks to forest ecosystems. It is obvious that the cumulative effects on forest ecosystems would be worsened, even if the relationships between these two factors and their results are not well known and are thus hard to forecast. With papers that highlight the effects of insect and disease invasions, climate change, forest management, and their interconnections, as well as strategies for anticipating, evaluating, and mitigating these effects, we present and summarize the content in this special issue of Forestry. The majority of these presentations took place during the 2014 XXIV IUFRO World Congress.