Spatio-temporal patterns and drivers of forest dynamics under global changeunderstanding the role of climate and forest-use legacies

Abstract

The impact of the drivers of global change (e.g. climate change and land-use change) on forests is increasing in recent years and a shift from a CO2 and N fertilisationdominated period to a climate-dominated period driving forest dynamics has been suggested. In addition, complex interactions between global change drivers are emerging, hindering our ability to predict future forest trajectories. Northern hemisphere forests have been managed by humans for centuries, but these centuriesold forest-uses have been rapidly abandoned since the mid-20th century, while its traces persist in the structure, distribution and species composition of today's forests (i.e. forest-use legacies). At the same time, the impacts of climate change on forest ecosystems are aggravating, but little is known about how forest-use legacies can interact with current climate change stressors to drive Northern Hemisphere forest dynamics. In this context, the main objective of the PhD thesis is to study how climate and forest-use legacies affect forest dynamics at multiple spatio-temporal scales. The thesis contains seven chapters. Chapter 1 presents a general introduction of recent patterns and drivers of forest dynamics under global change across space and time. Chapters 2-5 are four research chapters that address the overall objective of the thesis using a combination of continental to local data and decadal to centennial data. Finally, Chapter 6 discusses the contribution of the four research chapters in the context of shifts in Northern Hemisphere forest dynamics, highlighting the key role of climate and forest-use legacies, and Chapter 7 summarises the general conclusions of this thesis.