(i) The Mont Ventoux long term monitoring site includes Mediterranean-mountain model ecosystems made of beech-fir forests in dynamic colonization-dieback balance. Mont Ventoux is one of the intensive study sites (ISS) of the Evoltree scientific cooperation network for genotyping and phenotyping experiments on forest trees. Mont Ventoux is also a monitoring site for the ORCHAMP network, an observatory of biodiversity – management interactions in the French Alps.

A network of reciprocal transplants was installed to evaluate the genetic variability and local adaptation of silver fir in a changing environment. The common gardens of this network consist of transplanted material along a altitudinal gradients from 3 French Mediterranean mountains: Ventoux, Issole and Vésubie. Seedlings originate from several seed trees located at different elevations in each of the 3 mountains. This type of design makes it possible to observe how a local origin performs in its native environment versus in a new, foreign environment (Fig. 5) by studying several traits: growth, phenology and survival.

These reciprocal transplants on 9 sites (3 moutains x 3 altitudes), measured at an early age, show that genetic variability is found mainly between trees within altitudinal levels and that genetic differentiation between altitudinal levels is weak, indicating a general lack of strong local adaptation. Such a lack of interaction between genotypes and their environment is consistent with a capacity to adapt to a changing environment, within a magnitude of climate change not exceeding the ecological niche of the species.