The relative weight of ontogeny, topology and climate in the architectural development of three North American conifers

Knowledge of plant architecture allows for the retrospective study of plant development, and through modelling and simulation this development can be linked to environmental constraints and to predict responses to global change. In a recent study published in AoBP, Buissart et al. aimed to determine some of the main endogenous (ontogenic, topological) and exogenous (climate, site condition) variables driving the architectural development of three North American conifers (Picea mariana; Pinus banksiana; and Pinus strobus).

Conifer forest of black spruce and Jack pine.
Boreal conifer forest with lichen openings, mixing black spruce and Jack pine. Although frost in winter is one of the main constraints holding back forest productivity, climate warming reduces tree growth and architectural development, particularly with the increase of summer drought. Image credit: M. Vennetier.

A partial least square regression analysis was used to explain how architectural traits (annual shoot length, needle length, branching patterns and reproductive organs) are influenced by topological, ontogenic and climatic variables. The results of this analysis showed that the development of tree crown and reproduction were mainly controlled by annual shoot length and by variables related to branch topology (branching order, relative vigour) and ontogeny (tree age, ontogenic shoot age). The overall weight of climate variability, when compared to these factors, was weaker and differed among the studied species. The architectural development of the tree crown as a whole was however clearly dependent on interannual climate variability for the studied species. The results of this study may help to improve assessments of the future of these species in the context of climate change, particularly through better understanding of the interactions between exogenous (climate and site conditions) and endogenous factors (ontogeny, topology).

Researcher highlight

Michel Vennetier was first trained as forest engineer, then completed a PhD in forest ecology at Marseille University (France). He first worked as researcher in tropical forestry in southern India and Ivory Coast from 1978 to 1981, and as forest officer in north-eastern France up to 1987. Then he was in charge of the tropical forest research and development department for the French National Forest Office, based in Martinique (West Indies).

Since 1996, Michel has been working at the Department of Territories, National Research Institute of Science and Technology for Environment and Agriculture, with the aim of bridging forest research and management, through both scientific papers and technical guides, practical tools and training for forest managers or decision makers. His main current projects are related to climate change impacts on trees (growth, architectural development, phenology, pathology) and forest or riparian ecosystems (productivity, biodiversity and health – decline and die-back, soil quality, and interactions with wild fires.

Further reading

Buissart, F., Vennetier, M., Delagrange, S., Girard, F., Caraglio, Y., Sabatier, S.-A., … Nicolini, E.-A. (2018). The relative weight of ontogeny, topology and climate in the architectural development of three North American conifers. AoB PLANTS, 10(4). https://doi.org/10.1093/aobpla/ply045