a data system and a method for determining the harvestability and transportability of a stand marked for cutting , the method comprising : maintaining data on the properties of the soil of the stand ; determining a value for the harvestability and transportability of the stand , which value is dependent on said properties ; defining said value also on the basis of such conditions of said stand which affects said properties ; maintaining data on the harvestability and transportability defined for the stand . said property is one or more of the following : soil type , auxiliary attributes of the soil type , other permanent factors . said conditions are one or more of the following : snow depth , frost depth , soil moisture content , temperature , amount of rainfall , quantity of growing stock , relations between tree species , other variable factors .