In order to immobilize boron in wood, three kinds of resol-type phenol-formaldehyde (PF) resin with different P/F ratios were synthesized in laboratory and incorporated with three types of boron compounds to treat wood. The used boron compounds included boric acid (BA), borax (BX) and disodium octaborate tetrahydrate (DOT). The leaching test of boron from wood blocks was performed according to the American Wood Preservation Association (AWPA) standard E11-06. The boron content in treated wood blocks and leachates were determined by inductively coupled plasma optical emission spectrometer (ICP-OES). The results of experiment indicated that higher PF concentration is preferable for better boron fixation. There was no significant difference between the three boron compounds used in this experiment with only slightly higher boron leaching for borax. The “Two-step method” showed lower boron leaching than “One-step method”, which may be due to the lower boron retention before leaching caused by the boron leaching during PF impregnation process. Considering the P/F ratio, PFB (P/F ratio: 2.0) and PFC (P/F ratio: 2.2) showed a little lower boron leaching than PFA (P/F ratio: 1.6).

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