• Journal of the Korean Wood Science and Technology
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• v.47 no.6
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• pp.700-708
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• 2019

To verify the possibility of using resistograph to estimate the age of big old living trees, we selected three Zelkova serrata and seven Pinus densiflora in Goesan. The mean diameters at breast height of Z. serrata and P. densiflora were 102 (92-116) cm and 80 (65-110) cm, respectively. The heights measured from the ground using a resistograph ranged at 1.2-4.3 m and 0.6-1.1 m for Z. serrata and P. Densiflora, respectively. The most appropriate needle speed to determine tree-ring boundaries for measuring ring width was 1500 r/min for both tree species. Alternatively, the suitable feed speeds for Z. serrata and P. densiflora were 50 cm/min and 150 cm/min, respectively. From the measured data, the mean numbers of tree rings of Z. serrata and P. densiflora were 57 (43-68) and 104 (93-124), respectively, and the mean tree-ring widths were 4.27 mm (3.18-5.09 mm) and 2.93 mm (2.32-3.34 mm), respectively. A comparison between the time series of tree-ring widths by resistograph and that from the local master chronologies tallied for the heartwood part. Finally, this study showed that resistograph can be used to estimate tree ages when a local master chronology is available.

• Journal of the Korean Wood Science and Technology
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• v.47 no.1
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• pp.90-100
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• 2019

This study aims to determine the ideal feed speed of a resistograph to evaluate the number of tree rings in several tree species. The needle speed was fixed at 1,500 r/min. Herein, various tree species, such as Pseudotsuga menziesii, Pinus koraiensis, Abies holophylla, and Zelkova serrata, were considered for experiments. Results showed that the most proper feed speed for Zelkova serrata, Larix kaempferi, Pseudotsuga menziesii, Abies holophylla, and Pinus koraiensis was 75, 100, 100, 150, and 175 cm/min, respectively. However, in all the cases, the electric resistance values of tree ring narrower than 1 mm were not suitable for determining tree-ring boundaries. Upon comparing the inter-annual time series of ring widths and electric resistance values of resistograph, a meaningful synchronization was verified. If resistograph would be improved to the extent that it can measure tree rings narrower than 1 mm, it can replace the conventional method used for counting the number of tree rings in the increment cores. Additionally, it can also be used to investigate the tree growth.