This study was carried out to determine the effect of thinning on density extractives and lignin content of Pinus nigra Amold tree. Wood density was measured with computed tomography and 540 +/- 20 kg m(-3) were determined on control samples. Density of samples from thinning applied plot was 520 +/- 20 kg m(-3). The results showed that thinning slightly changes the density of wood and this change is caused by springwood content, In contrast, extractives and lignin content were not changed with thinning.