Results from surveys of the Swedish experiment in 1976, 1981, 1983 and 1985 are presented. The experiment was thinned when the average dominant heights were 10.3, 13.7 and 16.2 m, respectively. The increment of stem volume for the periods 1977–81 and 1982–85 is given in Tables 1 and 2, respectively. In comparison with unthinned control subplots, the volume increment for the periods 1977–81 and 1982–85 was reduced by the following relative figures:-treatment 2 with strip road width 3.5 m, 9 and 17% respectively-treatment 3 with strip road width 3.5 m, 16 and 14% respectively-treatment 4 with strip road width 5.0 m, 7 and 20% respectively