## 2 Materials and Methods
### The CARAIB Dynamic Vegetation Model
The stronger the wind, the lower aerodynamic resistance and this allows more efficient carbon and water transfers between soil/plant and atmosphere. Increases in evapotranspiration will tend to decrease soil water and thus plant NPP while increased carbon fluxes will tend to increase NPP. The model also needs input parameters characterizing the simulated plant species. Whereas previous studies used morpho-physiological traits of plant functional types (PFT; [72]), we looked for characteristics of individual species in an attempt to refine the simulations (Table 2). However, plant trait data available for African species remain scarce as already pointed out by [PERSON] and [PERSON] [44]. In absence of specific traits, PFT parameters are kept [70]. The selected species belong to two different PFTs: broadleaved raingreen tropical trees and broadleaved evergreen tropical trees. The best-characterized parameters at the species level are the tree height, the foliage carbon/nitrogen ratio (C:N) and the specific leaf area (SLA). The C:N and the SLA modulate the V\({}_{\text{Cmax}}\) according to the parameterization from [PERSON] et al. [74]. C:N also impacts autotrophic respiration. The intraspecific variations (standard deviation) of C:N and SLA inferred from available values are presented in Table 2. They are respectively lower and higher than the interspecific variations (5.4 g g\({}^{-1}\) for foliage C:N and 0.008 m\({}^{2}\) g\({}^{-1}\) C for SLA). The climatic tolerances (minimum temperature, T\({}_{\text{mins}}\), minimum soil water, SW\({}_{\text{mins}}\)) governing mortality under stress conditions and the threshold values (minimum yearly sum of growing degree-days above 5 \({}^{\circ}\)C GDD5\({}_{\text{mins}}\), and, for drought deciduous species, maximum soil water of the driest month, SW\({}_{\text{mavg}}\)) controlling germination are other species-specific parameters (Table 3). They are inferred from prescribed percentiles in their observed climate distribution, according to the method described by [PERSON] et al. [72] and [PERSON] et al. [75]. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & _Species_ & **Height** & **Root Depth** & **PFT 2** & **Fabaceae 3** & **Foliage C.N** & **SLA** \\  & & **(m)** & **(mm)** & **PFT 2** & **Fabaceae 3** & **(g g\({}^{-1}\))** & **(m\({}^{2}\) g\({}^{-1}\) C)** \\ \hline
1 & _Ceibu pentantra_ & 55 4  & 610 45  \\  & (20) & (910) & 1 & 0 & 30 & 0.037 \(\pm\) 0.019  \\  & _Cola acuminata_ & 20 4  & 910 & 2 67  & 0 67  & 12 67  & 0.041 67  \\  & _Elais guinensis_ & 25 4  & 600 4  & 2 & 0 & 30 & 0.030 \\ \hline
4 & _Guibourtia demusei_ & 35 4  & 910 & 2 6  & 1 6 & 21 \(\pm\) 0.7 6  & 0.027 \(\pm\) 0.006  \\  & _Lophira alata_ & 55 4  & 1440 & 1 & 0 & 30 & 0.020 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The selected species and the morpho-physiological traits for which some values were refined. Grey cells are species-specific values while white cells indicate initial plant functional type (PFT) values. The trait variations (standard deviation) for the foliage carbon/nitrogen ratio (C:N) and the specific leaf area (SLA) are given in addition to the mean value when the number of data is large enough. When species-specific trait data were found, the previous PFT values (standard in CARAIB 1) are noted between brackets. In order to evaluate the simulated current distribution of the studied species (corresponding to the reference 1980-1999 period in our study) and the change in distribution between present and future, it is necessary to determine a threshold below which the species is considered to be absent [50]. We used NPP instead of biomass thresholds, because uncertainty is larger for the second due to its dependence on an additional parameter (i.e., tree mortality rate). In analogy with the ENM method of setting a threshold under which one considers the probability of presence to be too low, we set the presence threshold at 100 g C m\({}^{-2}\) yr\({}^{-1}\) (close to the threshold used in [PERSON] et al. [50]).