Results from a tree species experiment in southwestern Sweden are given at a stand age 34 to 35 years. The experiment was established in 1957 on a fertile site with site index about 33 m for Norway spruce. The earlier generation was a Norway spruce stand which was highly affected by root rot (Heterobasidion annosum). The experiment was initially established aiming at studying the susceptibility of different tree species to root rot attacks. Later on the trial has also been used as a forest yield experiment. The following tree species are included in the experiment: 1. Norway spruce (Picea abies), 2. Scots pine (Pinus sylvestris), 3. Lodgepole pine (Pinus contorta var murrayana), 4. Sitka spruce (Picea sitchensis), 5. Grand fir (Abies grandis), 6. Serbian spruce (Picea omorica), 7. Silver fir (Abies alba), 8. Japanese larch (Larix leptolepis), 9. European larch (Larix decidua). The trial is designed as a randomized block experiment with three replications on the same site. The subplot net size is 400 m2 with a buffer zone of 2 m width. In Table 3, figures are given for both mean annual volume increment (from the time of the germination of the seed to the stand age of 34 or 35 years) and current annual volume increment during the last five years, 1983-87. The figures are means of three blocks. Increment relative Norway spruce are given within parentheses. In Appendix 1 the main characteristics for each species and each block are presented. The results indicate very large differences between the total yield of the studied tree species and the growth pattern over time. Some species, e.g. larch, represent species with a rapid development in the youth (sprinters), and e.g. silver fir represent species with a slow development at the early stage (stayers). Grand fir has up to now the highest total yield and silver fir the lowest. A true comparison between different species cannot be made until each species has reached the time of culmination of the mean annual volume increment. Nevertheless, the experiment at Susegarden already demonstrates interesting growth patterns for the species included in the trial. Future revisions of the experiment will deliver data demonstrating changes in the ranking between the species with regard to volume production, height increment, etc.
