Specimens prepared from Calabrian pine (Pinus brutia Ten.) wood were treated with borate-supplemented aqueous solutions of Calabrian pine bark powder, acorn powder, sumach leaf powder and gall-nut powder. Then, fire test methods containing flame source, without flame source and glowing stages was performed according to the ASTM E 160-50 American Standard. The results showed that the lowest temperature (323 °C) for the flame source stage was recorded for specimens treated with mixtures of boric acid and borax (BA and Bx). In the without flame stage, the lowest temperature (404 °C) was recorded for specimens treated with acorn powder and (BA and Bx) mixture. In the glowing stage, the lowest temperature (107 °C) was obtained for specimens treated with sumach leaf powder and (BA and Bx) mixture. The test specimens treated with aqueous solutions of plant extracts yielded higher heat release rates for all stages. Weight loss was lowest for specimens treated with a boric acid and borax mixture (63.4%). Wood specimens treated with aqueous solutions of plant extracts yielded higher weight losses compared to the untreated control specimens. The wood specimens treated with aqueous solutions of plant extracts had a negative effect on fire parameters. However, the boric acid and borax mixture had significantly better fire retardant effectiveness over untreated and plant extracts that were applied as secondary treatments.

Specimens prepared from Calabrian pine (Pinus brutia Ten.) wood were treated with borate-supplemented aqueous solutions of Calabrian pine bark powder, acorn powder, sumach leaf powder and gall-nut powder. Then, fire test methods containing flame source, without flame source and glowing stages was performed according to the ASTM E 160-50 American Standard. The results showed that the lowest temperature (323 °C) for the flame source stage was recorded for specimens treated with mixtures of boric acid and borax (BA and Bx). In the without flame stage, the lowest temperature (404 °C) was recorded for specimens treated with acorn powder and (BA and Bx) mixture. In the glowing stage, the lowest temperature (107 °C) was obtained for specimens treated with sumach leaf powder and (BA and Bx) mixture. The test specimens treated with aqueous solutions of plant extracts yielded higher heat release rates for all stages. Weight loss was lowest for specimens treated with a boric acid and borax mixture (63.4%). Wood specimens treated with aqueous solutions of plant extracts yielded higher weight losses compared to the untreated control specimens. The wood specimens treated with aqueous solutions of plant extracts had a negative effect on fire parameters. However, the boric acid and borax mixture had significantly better fire retardant effectiveness over untreated and plant extracts that were applied as secondary treatments.