To analyse the bark extractives, samples from five Iranian hardwoods trees such as black walnut, oak, alder, hornbeam and beech were prepared. Experiments showed that the total extractive content of these species were 29.8, 23.2, 17.9, 16.8 and 16.7 percent, respectively. The total ash. content were 19.2, 11.5, 9.5, 12.8 and 13.8 percent, respectively. Also, it was shoWn that the total phenolic materials were 26.3, 21.2,13.6,12.9 and 14.0 percent, respectively. By sequential precipitation, flobatanins, flobaphens and flavonoids were separated and measured quantitatively. Also, the percentage of tannins were found to be 40-50% which is less than those of softwoods (50-600/0); this means that the non-tannin extractives of hardwoods are more than those of softwoods. The lipophilic compounds of barks were determind quantitively using gas chromatography.. Also, the .chemical structure of a number of these compounds were suggested using GC-MS techniques.
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