Qualitative and quantitative analysis was performed on supercritical-fluid and conventional Soxhlet extracts of Betula pendula Roth., Alnus glutinosa (L.) Gaertn., and Platanus hybrida Brot. bark. The effect of the two extraction methods on extraction yields was compared. Lupeol and β-sitosterol were identified in the bark extracts by TLC and by GC-MS. The main components were betulin and lupeol followed by β-sitosterol; betulinic acid seemed to be a minor constituent. Betulin content was determined by RP-HPLC, with acetonitrile-water 80:20 (v/v) as mobile phase. Comparison of the extraction methods showed that supercritical-fluid (scCO2 + EtOH) and ethanolic Soxhlet extraction resulted in the highest extraction yields. Accumulation of betulin derivatives was higher in supercritical-fluid extracts (scCO2 + EtOH) than in conventional Soxhlet extracts.