Granföryngring på tallmark, hur ofta förekommer det?

Abstract: This survey was made during the summer of 2004 and the spring of 2005, on commission from the National Board of Forestry. The aim of this report was to investigate how often Norway spruce (Picea abies L. Karst), is planted on poor Scotch pine (Pinus Silvestries) sites and if it affects the yield of Norway spruce? In order to investigate this, data from 29 stands witch had a lower site index than T24 was collected. The investigated stands were situated in the southern-eastern Sweden. In 20 plots in each stand, the highest tree, age, number of seedlings, site index and tree species per stand were measured. Totally 580 plots were measured. The survey showed that 48 % of the investigated stands were planted with Norway spruce. Of the surveyed stands, 28 % had a small share of pine (10 % or less) and they will probably be dominated by Norway spruce in the future. Five of the 29 stands had a larger share of pine than 60 %. It is only those 5 stands that have a potential to develop into pure pine stands in the future. 8 of the 29 stands had a share of pine between 30-60 %. The remaining eight stands had a pine proportion of 10-30 %. Is the production effected when spruce grow on poor stands? The survey showed none or insignificant difference in growth between the two tree species. What speak in favor of the pine in a long period is that they are able to grow on dry and low fertile sites. Furthermore, Scots pine is less affected by butrot than Norway spruce. The high animal population during the last decades have forced the forest owners to plant more spruce instead of pine. This has and will affect the biodiversity and the landscape negatively for a long period in the future.