In our research we studied the economic potential; curbing costs; and elements of these of two woody stemmed invasive species: black locust (Robinia pseudoacacia L.) and tree of heaven (Ailanthus altissima Mill.) in a period 5 years. Questionnaires were sent to the relevant state institutions (national park directorates and state forest companies), other publicly available background information was collected and telephone interviews were carried out to complete the data. During the evaluation of data we found that the costs of black locust reduction were so high in national park directorates that they could not be compensated by the revenue from the sale. However, in the case of state forest companies, incomes were several times higher than costs each year. The judgment of tree of heaven was negative in all areas, so it could not be sold.