Tension wood is considered to be an important defect by the wood processing industries. A considerable amount of research has been done to determine the presence and structure of tension wood; however, there is a need to find a quick, practical, and applicable method to evaluate the severity of tension wood. This study investigated whether zinc-chlorine-iodide (Herzberg reagent) could be applied in determination of tension wood severity. Fagus sylvatica L. (beech wood), Populus alba L. (poplar wood), and Quercus robur L. and Quercus rubra L. (oak wood) species were used in this study. The results were compared with safranin/astra blue and acridine orange to verify the accuracy of the classification of the severity of tension wood. The results showed that the severity of tension wood was incorrect, and in particular the color reaction obtained with zinc-chlorine-iodide was weak; on the other hand, it was reliable for beech and poplar woods, where the color reaction was strong.