MODELING THE NET PHOTOSYNTHETIC RATE OF QUERCUS-MONGOLICA STANDS AFFECTED BY AMBIENT OZONE

A mathematical model predicting the ambient O-3 effect on the photosyn thetic rate of Quercus mongolica stands was developed for the temperat e deciduous forests in both the urban and the reference area in Korea. The diurnal pattern of hourly average O-3 concentration monitored at the study site was simulated using the Gaussian equation. The short-te rm effects of O-3 on net photosynthetic rate were estimated using a re lationship between ambient O-3 concentration and percentage reduction of net photosynthesis. Annual net production estimated by the model wi th the ambient O-3 concentration was 9.2% less than that of the model result without the ambient O-3 in the urban area, while the reduction rate was as small as 4.3% in the reference area. If O-3 concentrations were diminished or enhanced by 50% of the actual ambient condition, n et annual photosynthetic rate will increase up to 8% or decrease down to 5%. (C) 1997 Elsevier Science B.V.