Retrospective analysis of plant architecture: an extended definition of dendrochronology

Accurate expertise on plant development in space and time is fundamental to underpin conservation and management practices. Considering that trees are long-life organisms with a complex structure, understanding the rules of tree development, from seedlings to adult trees and for a given environment, is a steep task. Compared to field monitoring, retrospective analysis of plant incremental development (RAPID), based on the observation of morpho-anatomical markers allows accessing the past dynamics of plant architecture on many varied plants. However, it is clear that besides this very general approach, works based on axis thickening (mainly trunk) and growth rings structure (GR) remain a broad majority and they are recognized as a full-fledged discipline called dendrochronology. Etymologically, dendrochronology is the science (-logia) of reading the time (khronos) in trees (dendron). Nevertheless, it is clear that this definition applies equally to the crown expansion and to the understanding of the primary growth, branching or flowering processes through the study of morphological or macro-anatomical markers. Moreover, it is important to note that theses approaches can be applied not only in trees, but also in perennial herbaceous herbs or mosses that conduce some authors to propose the term herbchronology. Without trying to change the term of dendrochronology, etymologically limited, but widely used and deeply rooted in the scientific landscape, we support the idea that it should be extended to all approaches concerning the RAPID. In this presentation, we'll depict a summary of methods that allow accessing the past development of plants considering four major processes, growth I and II, branching, and flowering whatever the biological life-form. We'll discuss the close connection amongst the nature of theses processes, their phenology and the resulting morpho-anatomical structure. Considering that plant form integrates multiple environmental factors but, also, internal trade-offs among functions, we argue that integrative studies considering jointly morpho-anatomical markers in a RAPID approach offers powerful insights for diverse fields including plant biology, ecology, conservation. (Texte intégral)