The aim of the study was to show the impact of the peat extraction on the development and properties of organic soils and plant habitat in post-extraction sites. The study was conducted in the complex of the Trzcińskie Mokradła Peatlands (Sudetes Mts., SW Poland). The Trzcińskie Mokradła Peatlands began to form in Preboreal (10960–9330 ±50BP) so that they are one of the oldest peatlands in the Sudetes. We analyzed 8 soil profiles (42 samples). Peat forming process there is still active in the moderate or strong degree (PtII-PtIII). The floristic composition of the studied areas was typical of transition peatlands. Successive dry and moist periods were observed in the developed of organic soils. The time gaps in peat profiles covering hundreds of years prove their extraction in the past.