On the link between productivity and complexity and how it scales from tree to stand level

The adaptive capacity of forests is an integral part of their resistance and resilience when facing challenges imposed by climate change. Structural complexity might be a viable proxy for the adaptive capacity, as it is closely linked to productivity, and thus to the ability of forests to regrow tissue. Here, we used mobile laser scanning to investigate the link between individual tree complexity and productivity and how it scales from tree to stand level. We found a positive link between periodic annual increment and structural complexity for individual European beech ( Fagus sylvatica ), Douglas fir ( Pseudotsuga menziesii ) and Norway spruce ( Picea abies ) trees within temperate forests of northern Germany. Furthermore, we found evidence for a size-dependent relationship between a tree´s contribution to stand-level complexity and productivity at the plot level. Our results underline the close relationship between productivity and complexity and highlight the importance of multi-layeredness.