Short - term dynamics of structural complexity in differently managed and unmanaged European beech forests

Abstract

The dynamics of forest structure influence forest ecosystem functions and are modified by forest management and natural disturbances. Here, we quantified the dynamics of stand structural complexity of differently managed and unmanaged European beech (Fagus sylvatica L.) forests. We determined changes of different aspects of stand structural complexity between 2014 and 2019 using terrestrial laser scanning data from 42, one hectare-sized forest plots, representing even - aged forest management, uneven - aged forest management and unmanaged stands. Unmanaged forests showed no significant changes in stand structural complexity within the time frame investigated, due to the absence of major disturbances. On the contrary, managed uneven - aged and even - aged forest stands showed more pronounced dynamics in stand structural complexity than the unmanaged forests. In this context, uneven - aged stands with higher initial canopy openness showed a higher increase in structural complexity than stands with lower canopy openness, which could be attributed to growth responses of understory vegetation in lower strata due to improved light availability at the beginning of the observed time period. Dynamics of structural complexity under even - aged forest management strongly differed between different developmental stages, with young thickets and mature timber stands showing highest increases in stand structural complexity. Overall, we did not observe significant decreases in stand structural complexity within the observed time frame. Our findings need to be viewed in the context of long-term dynamics of forest structure and contribute to the understanding of how forest management can affect short - term structural dynamics in beech forests.