## 2 Materials and Methods
### Model Parameterization Versions  
In this study we used three parameterizations with different numbers of PFTs that were applied to the same forest site: a parameterization including only one species (one PFT) with averaged physiological attributes (M\({}_{1}\)), a standard parameterization with three PFTs representing different light demands (M\({}_{3}\)), and the parameterization with six PFTs (M\({}_{6}\)) representing different light demands and height classes (Table 2). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**PFT** & **Maximum Height [m]** & **Light Class** & **Exemplary Tree Species** & **Biomass [t ha\({}^{-1}\)]** \\ \hline
1 & \textgreater{}33 & Shade tolerant & _Strombosia scheffleri_ & 344.18 \\
2 & 16 \textgreater{} 33 & Shade tolerant & _Heinsenia diervilleoides_ & 10.20 \\
3 & 16 \textgreater{} 33 & Intermediate & _Ficus sur_ & 33.22 \\
4 & 16 \textgreater{} 33 & Shade intolerant & _Polyscias albersiana_ & 1.15 \\
5 & \textless{}16 & Shade tolerant & _Leptonychia usambrensis_ & 0.96 \\
6 & \textless{}16 & Shade intolerant & _Cyathea manniana_ & 0.09 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Derived plant functional types (PFTs) for forest site at Mt. Kilimanjaro as published in [30]. Tree species have been grouped according to their maximum reachable height and light demands. We distinguished three light classes: Shade-tolerant trees (climax species), shade-intolerant trees (pioneer species), and tree species of intermediate shade-tolerance. Aboveground biomass values were calculated from field measurements [30]. M\({}_{6}\) uses exactly the same parameter values as described in [PERSON] et al. (2013). M\({}_{1}\) with only one single PFT is constructed from M\({}_{6}\) by averaging the parameters, including weighting factors based on the biomass fraction of each PFT in the forest inventory (for biomass fraction, see Table 1). The same approach was used in M\({}_{3}\) for which we grouped species only according to their light demands. The derived model parameter values for the different versions (M\({}_{1}\), M\({}_{3}\), M\({}_{6}\)) can be found in Table 3 (overview) and in Appendix A (full list). The calculation of the weights for averaging the parameter values showed that M\({}_{1}\) is dominated mainly by shade-tolerant trees as 88% of the biomass belongs to shade tolerant species (Table 1). M\({}_{3}\) and M\({}_{6}\) include a mixture of shade-tolerant tree species, pioneer species and intermediate shade-tolerant species. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Model Parameterization Version** & **Number of PFTs** & **Averaging of Traits** \\ \hline \multirow{2}{*}{**M\({}_{6}\)**} & \multirow{2}{*}{Grouping by light demands and height classes} & \multirow{2}{*}{6} & No averaging. Original \\  & & & PFT grouping (Table 1) \\ \hline \multirow{2}{*}{**M\({}_{3}\)**} & \multirow{2}{*}{Grouping only by light demands} & \multirow{2}{*}{3} & Pioneers (PFT 4 + 6) \\  & & & Intermediates (PFT 3) \\ \multicolumn{1}{c}{} & & & Climax (PFT 1 + 2 + 5) \\ \hline \multirow{2}{*}{**M\({}_{1}\)**} & \multirow{2}{*}{No grouping. Mean species approach} & \multirow{2}{*}{1} & Mean species (PFT 1\(-\)6) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Overview of the used model parameterization versions in this study. The versions differ in the number of PFTs.