Abstract: The acetyl bromide lignin content of wood-forming tissue from Pinus koraiensis reaction wood was detected, and the FTIR and X-ray diffraction patterns were analyzed. The results showed that the lignin content of wood-forming tissue was lower than the mature wood, and the compression wood was higher than normal. The infrared spectrum results indicated that the characteristic absorption peak sites of hydroxyl and absorption band in 1 034-1 510 cm^-1 were obviously different between immature and mature woods. The relative absorption intensity of chemical functional group in immature wood was lower than mature one. The site and shape of characteristic absorption peak showed no significant difference among compression, opposite and normal woods. However, the relative absorption intensity of functional group in compression wood was higher than normal one. The diffracted intensity of wood-forming tissue was significantly lower than mature wood by X-ray diffracted pattern. Meanwhile, the diffracted intensity of compression wood was lower than opposite and normal ones. Moreover, the relative crystallinity of wood-forming tissue was significantly lower than mature xylem and it was lower in compression wood than opposite and normal ones. Hence, the chemical properties of wood-forming tissue are dynamic changing in wood formation and differences are existed between reaction and normal woods.

Key words: immature xylem, reaction wood, FTIR, XRD