In the present paper I described the results of the observations made on the visual characteristics such as the annual ring width and summerwood percentage of Pinus koraiensis Sieb. et Zucc. grown at out university forest. The results of the study are as follows: Characteristics of annual ring width and summerwood percentage 1. The range of dispersion of annual ring width and summerwood percentage are respectively 0.5-6.5㎜ and 5-50% on the normal wood and its arithmetic mean values are each 3.0㎜ and 24% on all sample trees. 2. The values of annual ring width of heart wood are larger than that of sapwood but on the contrary the values of summerwood percentage of heartwood are smaller than that of sapwood. On the other hand variations of these values are distingushed on the heartwood. 3. The values of annual ring width due to the parts of stem with crown. with clear length and at bottom showed that the largest values are given at the parts of stem with crown. But on the contrary the summerwood percentage values are largest at the parts of stem at bottom on all sample trees. 4. The values of annual ring width and summerwood percentage depending on the stand sides are not obvious. Horizontal and vertical variations of annual ring width and summerwood percentage 5. It was recognized that horizontal (radial direction) variations of annual ring width and summerwood percentage indicated two different patterns (the region of large fluctuation and that of small fluctuation) in a tree stem. These boundaries are seemed to appear at the parts of 12-15 annual rings from pith. 6. According to the increase of height in tree the values of annual ring width increase but the values of summerwood percentage gradually decrease. 7. But vertical variations of annual ring width and summerwood percentage on the sapwood are divided into two different parts (region of increased or decreased upwards and that of remained constant in successive height) in a tree stem and these limits are seemed to appear at the 7m of height in trees. Relations between annual ring width and summerwood percentage 8. The modes of summerwood percentage related with annual ring width are seemed to appear almost in the definite range (10-25%). 9. The relations between annual ring width and summerwood percentage show a highly negatine correlation on all sample trees.