The aim of our work was to assess the direction of change taking place in the forests of the regional directorates of State Forests (rdSF) based on measurable indicators used to assess sustainable development. Based on a synthetic index (Z), changes in the years 1993−2013 were evaluated for individual directorates. We identified the regions with the highest and lowest rates of change in terms of sustainable development dynamics. The analysis was performed using spatiotemporal variables and the main criterion for selecting the diagnostic variables was their availability and comparability over the analysed period. The rdSF variation was assessed with the synthetic index (Z), using the method of zero unitarisation. In 1993−2013, favourable changes over time were indeed recorded, reflecting the progress in implementing practices supporting sustainable development in forestry. However, large differences exist between the regional managements in this respect. For the analysed period, the most favourable conditions from the perspective of sustainable forest management were maintained in rdSF Kraków, rdSF Białystok and rdSF Toruń, while the least desirable conditions were found in rdSF Zielona Góra, rdSF Piła and rdSF Warsaw. The greatest rates of beneficial change, on the other hand, were found in rdSF Szczecin, rdSF Kraków and rdSF Wrocław. In turn, the lowest rates of change of the synthetic index (Z) were observed in the directorates of Katowice, Piła and Łódź. In summary, measurable indicators of sustainable development are a good instrument for measuring the pace of change in sustainable forestry. They are an effective tool for assessing and reporting progress over time and should also be used when planning and implementing development strategies.