WATER-BUDGET AND ANNUAL RING GROWTH OF PI NES IN THE REGION OF BERLIN

The quotient of actual transpiration (Ereal according to a modified RI JTEMA formula) to potential evapotranspiration (Epot according to HAUD E) is a suitable parameter to quantify water stress. Ereal/Epot of the months July and August show the strongest correlation to the annual r ing growth. Statistical analysis show that water stress periods might result in growth depression for several years. Simple nomogramms were developed to express water stress as a function of the climatical wate r balance and plant available water. These nomograms can be used to es timate depressions of ring growth influenced by water stress.