Current methods of artificial regeneration of pine and spruce are capable of high-volume production but the quality of the wood yield is well below that in naturally regenerated forests. Spruce plantations, for instance, are often fast growing, thus producing low-density wood. Similarly, pine trees often grow thick branches, even when planted fairly close together. A study on silvicultural models is currently in progress at the Silviculture research unit at Alnarp in southern Sweden, wit a view of finding ways of producing high-quality pine timber. A study has been made of a young pine stand in a shelterwood situated in southern Sweden. The stand is growing on a "pine-forest" site with a quality index of T27. The young stand has been naturally regenerated and cleaning has been carried out at a height of about three metres. Standards were left from the preceding stand until the trees in the young stand had reached a height of about six metres. The standards were then logged in at least three phases. Studies were made of the stand to determine both the volume production and the diameter of branches. From a comparison with a plantation it was found that growth in the naturally regenerated stand was heavily retarded, but that the diameter of the thickest branch up to a height of two metres above the ground was much smaller. Persson (1976) identified a clear correlation between the diameter of the thickest branch and the export-assortment yield of sawn timber. Volume production (mean annual increment) was estimated to be 20% lower than in plantations with normal spacing. However, it is likely that the loss in value associated with lower volume production is compensated for by the low regeneration costs and a substantial increase in the quality of the harvested timber. The study has found that it is possible to regenerate high- quality pine stands even on fertile sites. The project is to be expanded to include studies of stands in other parts of southern Sweden. Trials are to be conducted to determine the effect of reforestation method, young-stand density and the retention of shelter-wood on quality and increment in the pine stands.
231 (Natürliche Verjüngung) 232.4 (Bestandesgründung durch Pflanzung) 562.2 (Baumgruppen und Bestände im allgemeinen) 665 (Einfluß der Stamm- und Blochgröße auf die Kosten) 666 (Einfluß bestimmter Betriebsformen und waldbaulicher Systeme auf die Kosten) 174.7 (Coniferae [Siehe Anhang D]) [485] (Schweden)
