Revisiting silvicultural systems: Towards a systematic and generic design of tree regeneration methods

Understanding and mimicking regeneration processes in forests is crucial to sustainable forestry and forest conservation, since they largely determine the structural and ecophysiological traits as well as the ecosystem goods and services of forest stands. The techniques employed in achieving tree regeneration include the active manipulation of forest structure and are formally described by silvicultural systems. In the past, most silvicultural systems were developed locally and the corresponding authors used names and terminology that greatly varied and were often ambiguous. In addition, although local developments, silvicultural systems were often presented as “package deals” and individual components were not sufficiently defined to allow for adaptations in applications elsewhere. We critically reviewed the basic components and variants of silvicultural systems as well as their combinations in order to develop a unifying terminology that allows a better communication of regeneration methods and inspires the continued creation of new ones. Finally we applied the terminology elaborated in our review to an example of classifying silvicultural systems from Poland in order to show how existing silvicultural systems can be more clearly re-interpreted. We found that our review and analysis opened new insights on silvicultural systems that pave the way to more detailed and systematic future research in regeneration techniques. Silvicultural systems applied to high forests are often, with few modifications, also applicable to coppice forests and vice versa. Silvicultural systems also form an important element of close-to-nature or continuous cover forestry (CCF), as they contribute to diversifying forest structure by introducing new tree cohorts and the way how rigorously silvicultural systems are applied in various countries much depends on the time elapsed since the adoption of CCF.