Un article vient de paraître dans la revue « Agricultural and Forest Meteorology » sur l’importance de l’espèce d’arbre de la canopée sur la capacité du couvert forestier à tamponner les températures en période estivale:
Perot, Thomas, Marc Saudreau, Nathalie Korboulewsky, Anders Mårell, et Philippe Balandier. Capacity of a forest to buffer temperature: Does canopy tree species matter? Agricultural and Forest Meteorology 371 (2025): 110646. https://doi.org/10.1016/j.agrformet.2025.110646
- La température de l’air a été suivie dans des peuplements de chêne sessile et de pin sylvestre de 2018 à 2020 sur le dispositif OPTMix ;
- Les effets de l’espèce d’arbre et de la densité du peuplement sur la capacité tampon ont été testés ;
- Le rayonnement incident et le rayonnement intercepté par la canopée ont été pris en compte dans les analyses ;
- L’espèce d’arbre avait un effet significatif sur la capacité du couvert forestier a tamponner les températures ;
- Les peuplements de chêne procuraient un effet tampon supérieur aux peuplements de pin à rayonnement intercepté égal.
Résumé :
We studied the effects of tree species and tree density on the capacity of a forest to buffer understory temperatures during the summer period. We dissociated tree-species and light effects by integrating incident solar irradiance and its proportion intercepted by the canopy into our analyses. We measured solar radiation and air temperature over three consecutive years (2018, 2019 and 2020) in 16 plots in Central France composed of mature stands of sessile oak and Scots pine with three types of composition: monospecific oak, monospecific pine and oak-pine mixture, and two levels of tree density. Air temperature and solar radiation were recorded simultaneously in the experimental plots and in a reference plot without forest cover.
Our results show that the higher the incident irradiance the greater the difference in minimum temperature, and that the higher the intercepted irradiance the greater the difference in maximum temperature between below-canopy and open conditions. We found that tree species had a significant effect on the buffering capacity even when the light factor was taken into account. For a given incident irradiance and a given proportion of intercepted irradiance, the pine plots buffered understory temperatures less than the oak plots. Our results also show that higher maximum temperatures occurred in the understory than in open conditions for low values of intercepted irradiance and high values of incident irradiance, especially in the plots where Scots pine was present. The two species differ in leaf albedo and in their ability to regulate transpiration during droughts and these two characteristics may explain our results. Our study shows that Scots pine is less able to buffer summer temperatures than sessile oak. These results are of interest to forest managers since reducing stand density and mixing tree species are considered to be silvicultural strategies that can help cope with climate change.
