The forest no longer shows the steady growth increase that it has had over the past century. In the past 10 years, Sweden has lost 15% of its annual growth compared to the record years around 2010. It is likely that the decline is due to climate change, but it is not possible to say with today's knowledge whether this is a temporary slump or the beginning of a continued downward trend. In addition, it is even more uncertain whether the growth-enhancing silvicultural measures that have traditionally been used in forestry may further affect the vitality and resilience of the forest in a future climate. It is therefore of crucial importance that new research is carried out to understand how different climate-related extreme weather events may affect growth in the future.

The question of forest growth cannot be answered with traditional forestry experiments, but must be investigated with the help of long-term, large-scale studies that experimentally test the relationship between cause and effect. Here we plan to use funds from the Kempe Foundations together with the Wallenberg Initiatives for Forest Research (WIFORCE) to enable the construction of a large and well-designed climate experiment that is unparalleled. Our hope is that with combined resources we will be able to test central water limitation (drought) and warming treatments with an instrumentation, scale and repeatability that makes it one of the leading forest climate experiments in the coniferous forest belt.