Forest cover change, climate variability, and hydrological responses

Understanding ecohydrological response to environmental change is critical for protecting watershed functions, sustaining clean water supply, and other ecosystem services, safeguarding public safety, floods mitigation, and drought response. Understanding ecohyhdrological processes and their implications to forest and water management has become increasingly important in the Anthropocene (Li et al., 2017; Sun & Vose, 2016). In forested watersheds or landscapes, the complex relationships between climate and forest cover are commonly viewed as two key drivers of ecohydrological processes. Quantifying these relationships and the ecohydrological response to change is key to improved land‐use planning and management in forested watersheds. This special issue includes 11 selected papers presented at the 4th IUFRO (International Union of Forest Research Organization) Conference on Forests and Water in a Changing Environment held from July 6–9, 2015, in Kelowna, British Columbia, Canada. This collection represents the most recent studies on forest ecohydrological processes under a wide range of geographic regions and environmental settings. The first four papers in this special issue examine the relationships between climate and ecohydrological processes. Liu (2017) investigated the response of dead forest fuel moisture to climate change in the continental United States, an area of frequent wildfires and where controlled burning is used to reduce fire hazards. Using the empirical fuel moisture model of the US National Fire Danger Rating System, the study predicted an overwhelming decrease in fuel moisture across the United States, mainly due to an increase in air temperature, further suggesting future increases in frequency, size, and intensity of wildfires. Liu, Harper, Dell, Liu, and Yu (2017) examined vegetation responses to a long drought period (2002–2010) on the Australian continent and found a dramatic decline in both normalized difference vegetation and leaf area indices particularly in places where rainfall decreased the most. Using the FORECAST‐Climate model, de Andrés et al. (2017) simulated the responses of a mixed Scots pine and European beech forest to climate change. They found improved water use efficiency in the mixed species as compared to monoculture beech or pine stands and suggest that plantings of pine and beech mixed forest could be an effective climate change adaptation strategy on drought‐prone sites in northern Spain. Zhang, Hickel and Shao (2017a) clearly demonstrated the critical role of climate in