Regeneration in continuous cover forestry systems

• Main Author: Erefur, Charlotta
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2010
• Subjects: The Needle; Northern Sweden
• Online Access: https://pub.epsilon.slu.se/2277/; https://pub.epsilon.slu.se/2277/1/erefur_c_100426.pdf

The overall aim of the studies underlying this thesis has been to qualify and quantify the regeneration of tree species in a range of typical growing environments of possible Continuous Cover Forestry (CCF) silvicultural systems in boreal forests of northern Sweden. Data presented in Papers I and II show that the light environment did not differ significantly between points at different distances to trees, but it was clearly affected by the stand stem density (SSD). On a north-facing slope, the emergence rates of direct-seeded seedlings were highest (50 and 44% of germinable Pinus sylvestris and Pices abies seeds, respectively) in a stand with an SSD of 150. In contrast, on a slope with a southern aspect the conditions in SSD 0 favoured emergence of P.sylvestris (41%). For planted P. abies, fertilised seedlings in SSD 0 grew the most (22.2 cm in height on the North and 34.2 cm on the South slope). Establishment of both P. sylvestris and P.abies seedlings was more controlled by the general (light) conditions of the stand than their orientation and distance with respect to the nearest tree. In Paper III, seedling survival and growth were compared between a clear-cut, a multi-layered shelterwood (MLS), and a single-layered shelterwood (SLS). The needle and root biomass of seedlings of both species, growing in identical (good) soil conditions, was highest in the clear-cut (P. sylvestris 63 and 14 g, respectively; P. abies 34 and 12 g, respectively). With those soil conditions, there were also no significant differences in growth, at least for P.sylvestris, between the MLS and SLS, although with increased belowground competition seedlings grew more slowly in the MLS. In Papers IV and V, the establishment and growth of Betula pendula, Populus tremula, P. sylvestris, Larix sibirica, Abies lasiocarpa, and P. abies, planted in a Chequered-Gap- Shelterwood-System (CGSS) with 0.135 ha gaps under a shelter of pine forest, were compared in a 30-year-old (“younger”) stand and a 50-year-old (“older”) stand. Solar radiation ...