Possibility of using non-destructive spectrophotometery to detect the poplar tension wood and spruce compression wood in freshly cut and dried timbers

In this study, the possibility of using spectrophotometery and CIELAB technique to detect reaction woods in poplar tension wood and spruce compression wood was examined. Thus, two sample trees of spruce (Picea abies) and poplar (Populous nigra) containing reaction wood were felled in a forest belonging to ENGREF (the National Engineering School of Forestry close to Nancy in France). Then lightness (L*) and reflectance (R) parameters in reaction wood and normal wood both in green and dry conditions were measured. The results showed that in the green condition, the spruce compression wood had less lightness than the normal wood and the lightness of compression wood increased as a result of drying. The difference between the lightness and reflectance parameters of the two types of reaction woods and those of their corresponding normal woods was statistically significant in the green condition. Consequently, it can be concluded that the macroscopical detection of reaction wood is easier in the green condition than in the dry samples.