Interactions between vegetation and climate variability: what are the lessons of models and paleovegetation data

The climate reconstruction by using pollen data is classically done by statistical methods. The use of a conceptual model of niches show a few weaknesses of this approach which is not enough supported by causal relationships. A solution is to take into account ecophysiological processes through a mechanistic model. On the one hand, these models help to test the biases that can bring some changes in the distribution of the extremes, and, on the other hand, they help to understand the effect of some external constraints such as the concentration of the atmospheric CO2. At a shorter time scale, dendrochronological series are useful to test the response of the Aleppo pine to a warming combined to a stronger water stress. This approach is facilitated by the use of vegetation models used in inverse mode or with climatic scenarios. This paper illustrates that purpose through several examples.