Integration of gap dynamics in the forest conversion of pure spruce stands in the Ore Mountains

The study is part of the BMBF project " Sustainable methods and ecological processes of the conversion of pure stands of spruce and pine into the near-natural mixed stands".  Gaps resulting from damaging events (disturbances) can be integratively used for forest conversion by means of natural regeneration and passive advance-planting. The processes taking place in gaps, i.e. gap dynamics, are thus playing an important role. They include the above- and belowground regeneration of edge trees and the changes resource supply resulting from newly available space. A Masters thesis will investigate the development of natural regeneration in these gaps.
A total of 6 gaps in two size classes (15 and 30 m diameter) and 3 age classes (35, 70, and 105 years) was selected from all gaps present on the sites. All study sites are located in the central Ore Mountains at an elevation of 550-650 m a.s.l. on sites with moderately moist cambisols above gneiss featuring a moderate nutrient supply. Gap ages range from 4 to 5 years.
The regenerative processes of the edge trees will be characterized by the growth of crown, stem, and roots. Based on these investigations, growth model will be parameterized and combined with variables of gap climate (soil water, radiation). Depending on the stand age and gap size, we will thus provide decision support for restoring stable mixed forest stands. In addition, we will assess where and in how far silvicultural measures which attempt to install regeneration initials of economically relevant tree species are necessary and/or reasonable. The punctiform measurements on our study sites will be complemented by characterizing the gap frequency distribution of the stands in order to assess the economical relevancy on a regional scale.