In the period 1988-1998, when the main layer (poplar clone Robusta) was 27-38 years old, leaf area indices of both tree and shrub layers have been assessed. Total leaf area index varies between 7.38 and 7.61 ha.ha-1 with the negative tendency towards the year 1998. This decrease is caused mainly by the over-aged tree layer and die-off of some individuals with worse biosociological position. The health state of the stand has been good during the period and no abrupt decrease or drop of the leaf area index after 1992 (damming the Danube) could not be observed. The decreased groundwater level is still contacting the loamy layer, where the root systems of trees and shrubs are situated.