## 3 Materials and Methods
### Validation of the Modified Miami Model
\begin{table}
\begin{tabular}{c c c c} \hline
**Species** & \multicolumn{2}{c}{**BM\({}_{\text{max}}\)**} & \multicolumn{2}{c}{**MAT\({}_{\text{nat}}\)**} \\ \cline{2-4}  & Mg ha\({}^{-}\)a\({}^{-1}\) & \({}^{\circ}\)C & **References** \\ \hline _Picea abies_ Karst & 10.8 & 0.5 & [48, 49, 50, 51, 52, 53] \\ _Pinus sylvestris_ L. & 7.3 & 0.1 & [50, 51, 52, 53, 54, 55] \\ _Abies alba_ Mill. & 9.1 & 2.6 & [50, 51, 52, 53, 54, 55, 56, 57] \\ _Larix_ spp. & 9.1 & 3.9 & [50, 51, 52, 58, 59, 60, 61, 62] \\ _Pseudotsuga menziesii_ [PERSON] & 14.2 & 7.6 & [52, 63, 64, 65, 66, 66] \\ _Betula_ spp. & 6.7 & 0.3 & [50, 51, 53, 55, 67] \\ _Anus glutinosa_ ([PERSON]. & 7.7 & 2.7 & [51, 53, 68] \\ _Populus nigra_ L. & 8.8 & 9.1 & [69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79] \\ _Populus tremula_ L. & 8.8 & 1.9 & [70, 71, 76, 77, 78, 79] \\ _P. tremula_ L. _x p. tremuloides_ Michx. & 11.4 & 1.0 & [71, 76, 80, 81] \\ _Salix_ spp. (short rotation) & 12.5 & 5.3 & [50, 71, 74, 75, 82, 83] \\ _Fraximus excelsior_ L. & 8.7 & 9.6 & [51, 55, 75, 84, 85, 86, 87] \\ \hline \end{tabular}
\end{table} 
Table 2: Literature values of the maximum biomass production of a species in dry matter (BM\({}_{\text{max}}\)) and the mean annual temperature of the native distribution area or the average mean annual temperature of the reported growing tests (MAT\({}_{\text{nat}}\)) for different species. Most of the species have ABM values in the range of 2 to 4 Mg ha\({}^{-1}\)a\({}^{-1}\) for the site in southern Sweden (Figure 5 grey). Eight of the 19 species have an ABM between 4.5 and 6 Mg ha\({}^{-1}\)a\({}^{-1}\). This is often less than half of the maximum biomass production presented in the literature (BM\({}_{\rm max}\)). The three species with the highest ABM are hybrid aspen (_P. tremula_ L. \(\times\)_P. tremuloides_ Michx. ), Norway spruce and reed canary grass. In northern Sweden (Figure 5, black), the only species with a biomass production higher than 4 Mg ha\({}^{-1}\)a\({}^{-1}\) are Norway spruce and hybrid aspen, while Scots pine, birch and aspen (_Populus tremula_ L.) show a production of more than 3 Mg ha\({}^{-1}\)a\({}^{-1}\). Reed canary grass also has a relatively high productivity, which explains why it is cultivated to such an extent in the boreal regions, a fact also supported by literature [38, 40, 95]. Of the broad-leaved trees, only the pioneer species, such as birch and aspen or alder (_Alnus glutinosa_ (L.) [PERSON]), appear able to survive under boreal climatic conditions, which is also supported by forest inventory data [46]. The findings for other species are also supported by the literature: for _Paulownia_ plantations, a MAT of at least 9 \({}^{\circ}\)C [97] or at least the sixth climate zone [98] are recommended, due to the low frost resistance of the fast growing variants of this species [26, 27]; for _Miscanthus_, problems of cultivation in colder climate zones were reported [24]. Silver fir (_Abies alba_ [PERSON]) and Douglas fir (_Pseudotsuga menziesii_ (Mirb.) [PERSON]) favour not overly cool climates with a relatively high precipitation [6, 65, 99, 100]. For the species native to Sweden, the inventory data, such as the percentages of different species in the forest, support the results of the model [46]. The results, which include (1) a comparison of different species on one site and (2) a comparison of two different sites, show that it is possible to estimate the ABM for different species on different sites using the modified Miami model. This means that this model can be used as a decision support for the plantation of species under different climate conditions, because it shows that the extent of temperature or precipitation are limiting factors for biomass production. The results also demonstrate that both requirements, namely the variation in biomass production and the influence of the minimal temperature for the different species, can be fulfilled. Nevertheless, it is only a basic formulation to be optimized and validated with a larger quantity of reference data.