The crown shape of Araucaria araucana (Molina) K.Koch under the different age stages and ecological conditions in natural habitats

The geobotanical studies on transects of the natural mountain forests in the State of Neuquen, Argentina have been carried out. Transects were established on the slopes, starting from the clearings at the bottom of valleys (800 m above sea level) to the true Araucarian forests (1,600 m). Four types of forest communities of different floristic composition with the participation of Araucaria araucana have been defined. Vertical profiles of the mentioned forests have been drawn. Crown architecture of A. araucana was described in details at the different age states of trees. The dependence of the crown's shape from the environmental conditions of the phytocenosis was revealed. The position of A. araucana in the phytocenosis and its relations inside it greatly influence its crone shape in each particular age.