Characteristic features of leaf apparatus formation and transpiration of coniferous stand

Transpiration of forest stand makes up a large fraction of the total forest evapotranspiration. Its estimation for a particular forest area is a challenging task. Consumption of the soil water by the forest stand is closely related to mineral nutrition and foliage formation. Therefore, a study of the relationship among foliage development, mineral nutrition, and transpiration of stands of different age and different growing conditions is needed for more accurate estimations of evapotranspiration. The aim of this work is to study the influence of soil fertility on the needles’ formation and transpiration of forest stands This work is based on the analysis of other studies. It is shown that, as bonitet improves, concentration of nitrogen in the soil water consumed by stands increases. The increase of soil fertility is accompanied by the reduction of specific mass in needles. The influence of the stand productivity on the total mass of needles and on the transpiration of the forest depends on the bonitet class and age. For a young and middle-aged stand the mass of needles, and thus transpiration, increases as bonitet improves. This tendency may not persist for mature and overmature stands. The method of calculation of pine and spruce needle mass using the stem volume and its increment is proposed.