Skip to main content

PRESS RELEASE: Choosing the best seeds to help sessile oaks adapt to future climates

Forest planting is one of the levers to mitigate climate change. The origin of seeds is crucial to optimise the success of tree planting and their adaptation to future climates. INRAE and the ONF (French Forestry Office) conducted a vast study over 30 years using a collection of around 100 populations* of sessile oak from all over Europe and spread over four experimental sites in France to identify the best seed sources for this species. Their results, published in Annals of Forest Science, show that tree populations from regions with a long tradition of forestry have the best combination of ecological and silvicultural traits (survival, growth, form, adaptation to climatic variations). The scientists recommend using about 30 seed sources for planting sessile oaks in France, combining the diversity and adaptation needed to respond to climate change.

The drought of 1976, which corresponds to a strong episode that affected France and part of Europe between the autumn of 1975 and the summer of 1976, resulted in an increase in the mortality of forest trees, particularly pedunculate oaks. These die-offs prompted research into the adaptation of oaks in general and the sessile oak in particular, which remains the most widely planted deciduous species in France. The ONF and INRAE joined forces and assembled a collection of 110 sessile oak populations from France (70 populations) and Europe (40 populations) on four experimental sites located in the departments of Sarthe, Cher, Nièvre, and Moselle. For thirty years, scientists studied the evolution of the characteristics of interest of these oaks (survival, growth, shape, adaptation to climatic variations) and their genetic variability. The aim was to identify the best seed sources for planting sessile oaks capable of adapting to future climates.

Surprisingly, the research team found that oak populations with similar traits and genetic variation did not cluster according to the 19 geographical areas of origin of sessile oaks, areas defined by their climatic homogeneity (so-called 'regions of provenance'). Instead, the study shows the effects of silviculture on the organisation and variation of oak traits. Thus, the oaks with the best compromise between survival, growth, adaptation to climatic variations, and tree form came from regions with a long tradition of forestry, sometimes going back to the Middle Ages, such as Bourbonnais, Berry, and the Loire Basin. In these regions, the trees have been selected for these characteristics by human intervention over several generations.

The scientists make several recommendations for successful plantations of sessile oaks that contribute to the adaptation of forests to future climate conditions. They identified 34 oak populations with good combinations of traits as seed sources for future plantations. They also highlight the importance of mixing seed sources to maintain genetic diversity in plantations, which is essential for adaptation to climate change.

* A population of a tree species refers to a group of trees coming from the same region and having grown in the same environment (soil, climate, forest management...).


Girard, Q., Ducousso, A., de Gramont, C.B. et al. Provenance variation and seed sourcing for sessile oak (Quercus petraea (Matt.) Liebl.) in France. Annals of Forest Science 79, 27 (2022).

Ducousso, A., Ehrenmann, F., Girard, Q. et al. Long-term and large-scale Quercus petraea population survey conducted in provenance tests installed in France. [Data paper]. Data INRAE repository. Annals of Forest Science 79, 26 (2022).


INRAE Press Release:

Official journal of