ISHS Acta Horticulturae 496: International Symposium on Urban Tree Health
SOME ARCHITECTURAL MARKERS OF PLANE TREE DEVELOPMENT (PLATANUS X ACERIFOLIA (AITON) WILLD.): CONTRIBUTION TO THE ESTABLISHMENT OF AN ONTOGENIC BASED DIAGNOSIS. |
| Authors: | P. Genoyer, C. Atger, C. Edelin, Y. Caraglio |
| Keywords: | Ontogeny, diagnosis, Plane tree, vegetative morphology, trauma |
| Abstract:
Ontogeny of the plane tree (Platanus X acerifolia (Aiton) Willd.) is characterized by a set of architectural, i.e. structural and morphological changes, which follow one another in a specific and unique order (fig. 1 to 7). This succession is called the Plane tree ontogenic sequence. The ontogenic state assessment of healthy and unharmed Plane tree can be determined in reference to this sequence. The ontogenic potential assessment of such trees is based on their ontogenic state and their growth dynamics. The ontogenic state indicators of young Plane trees (fig.1 to 3) are their global organization branching order and lateral branches organization (symmetry, type, direction, branching order, partial reiterative, process characters, morphology of growth units, growth direction). From the start of the permanent crown building until the end of senescence phase, the ontogenic state of a Plane tree is fixed by the organization and morphology of the whole crown and the main branches (total reiterated complexes accumulation, fig. 4 to 8). Total reiteration order, direction, comparative height and width and branching order of successive reiterated complexes, growth direction and morphology of apical shoots are the main ontogenic state indicators. Are these markers efficient to indicate the ontogenic potentialities of urban stress or mutilated trees? The regenerating processes of two injured tree populations (ontogenetically old one vs ontogenetically young mutilated ones) have been studied as soon as they were injured (fig. 9 to 11). Prognosticating the development state of such armed or mutilated trees is not possible soon after the trauma: regeneration processes differ from ontogenic specific sequence because aging and rejuvenation - like phenomena occur during the reaction phase. They prevent actual ontogenic aging of the whole tree to be observed. Ontogenic assessment of armed trees needs a better understanding of the varied regeneration ontogenic sequence. | |
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