Abstract: The dynamics of biomass, nutrient storage and longterm productivity of Korean larch plantations growing in Mengjiagang Forest Farm of Heilongjiang Province, northeastern China, following continuing rotation cropping, was studied by employing a ecosystem simulation model (FORECAST, forestry and environmental change assessment) of incorporating rotation length, forest floor litter management and logging slash treatment. The conclusion was the followings: the suitable rotation of sustaining the longterm productivity under the general treatments should be more than 35 years; the soil productivity of larch plantation using different felling cycles could be improved by reserving litter fall, and was especially obvious to the short felling circle; the treatment of keeping all logging slash could sustain longterm productivity of larch plantation using different felling cycle.