Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Some architectural aspects of tree ageing. | 194s Ann. Sci. For. 1989 46 suppl. 194s-198s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Some architectural aspects of tree ageing D. Barthelemy c. Edelin and F. Halle Laboratoire de Botanique Institut Botanique UA327 du CNRS 163 rue A. Broussonet 34000 Montpellier France Introduction Despite the numerous investigations on tree ageing among which the work of Schaffalitzky de Muckadell 1959 is certainly the most famous we are still far from being able to give a definition of this general process. This we believe mainly results from the difficulty to identify precise markers of development and of the physiological state of an old tree. Using the concepts of architectural model and reiteration Halle et al. 1978 architectural studies along with other sectors of research may contribute to increasing our knowledge of tree ageing by analyzing and describing the successive morphogenetic processes that occur between crown construction and the death of woody plants. We have only a few data on this problem but recent observations lead US to distinguish 3 major kinds of architectural events during this period. The reversion to a juvenile-like architecture Between germination and crown construction the tree shows a series of architectures that arise according to an invariable sequence of genetically determined events. For instance in Virola surinamen-sis Roland. Warb. Myristicaceae a South American tropical tree which conforms to Massart s model the first phase of growth consists of the development of tiers of plagiotropic branches on the orthotropic trunk a very simple architecture which corresponds to the architectural unit Edelin 1977 of this species. The second phase which starts when the organism is 5-7 m high is marked by the development of forks at the extremity of the branches each axis of this fork is a partial reiterated complex. The third phase begins when the tree is 15-20 m tall total reiterated complexes grow out vertically at the tip of the .
