Changes in Tree Ring Width and Density of Pinus thunbergii Growing in the Vicinity of Industrial Complex in Korea

Abstract

There has been a decline in tree growth since the operation of factories at Pinus thunbergii forests around a petrochemical industrial complex in Korea. This study was carried out to investigate the effects of air pollution on tree ring width and ring density of Pinus thunbergii. Soft X-ray densitometrical method was used. Decline of ring width was the highest during 3 years immediately after the operation of factories. The percentage of decrease was almost bigger immediately after operation as compared with before. Maximum density (MAXD), and the difference (DD) between maximum density and minimum density (MIND) generally decreased since operation of factories, while minimum density increased in the beginning of operation of factories. There was a significant correlation between ring width and high temperature, and precipitation in the beginning of growing season, respectively. There was also a negative correlation between annual mean concentration of SO₂ and ring width at 5% level (r=−0.627*). It is suggested that the decline of ring width after operation of factories was due to compound factors of air pollution and climate. The effect of other factors should be still more studied.

Key words:

• air pollution
• Pinus thunbergii
• ring density
• tree ring width