# Carbon and Nitrogen Pools and Fluxes in Adjacent Mature Norway Spruce and European Beech Forests
## 3 Results
### Carbon and Nitrogen Fluxes
#### Water, Carbon and Nitrogen Fluxes in Precipitation and Soil Leachate
Similar seepage fluxes of water in 30 cm and non-significant (\(p=\) 0.22) differences in DOC concentrations (7.1 \(\pm\) 2.4 mg\(\cdot\)L\({}^{-1}\) in spruce and 5.4 \(\pm\) 1.2 mg\(\cdot\)L\({}^{-1}\) in beech) resulted in comparable DOC leaching at the 30 cm depth (Table 5). The concentration of DON in the spruce forest floor (1.64 \(\pm\) 0.55 mg\(\cdot\)L\({}^{-1}\)) was significantly (\(p<\) 0.001) higher compared to the beech forest floor (1.17 \(\pm\) 0.25 mg\(\cdot\)L\({}^{-1}\)). However, forest floor DON fluxes were comparable among stands. DON fluxes dominated the total N flux in the forest floor of both stands. No significant differences (\(p=\) 0.30) were measured in NO\({}_{3}\)\({}^{-}\) concentrations in forest floor soil solution among stands (0.97 \(\pm\) 1.28 mg\(\cdot\)L\({}^{-1}\) in spruce and 0.88 \(\pm\) 1.19 mg\(\cdot\)L\({}^{-1}\) in beech). Total N loss from the forest floor was similar (6.5 kg\(\cdot\)ha\({}^{-1}\cdot\)year\({}^{-1}\)) in both stands. In mineral soil, at a depth of 30 cm, DON concentration was similar in both stands (0.30 \(\pm\) 0.25 mg\(\cdot\)L\({}^{-1}\) in spruce and 0.20 \(\pm\) 0.10 mg\(\cdot\)L\({}^{-1}\) in beech). Although DON dominated total mineral soil N flux in the spruce stand, NO\({}_{3}\) was the dominant form of N leaving the mineral soil in the beech stand. A large and significant difference (\(p<\) 0.001) in NO\({}_{3}\)\({}^{-}\) concentration was measured between stands (0.12 \(\pm\) 0.12 mg\(\cdot\)L\({}^{-1}\) in spruce and 1.28 \(\pm\) 1.40 mg\(\cdot\)L\({}^{-1}\) in beech). DOC/DON ratios were not statistically different between stands for either forest floor or mineral soil (Table 5). \begin{table}
\begin{tabular}{c c c c c c} \hline
**2013–2015** & **H\({}_{2}\)O** & **DOC** & **DON** & **N-NH\({}_{4}\)** & **N-NO\({}_{3}\)** \\ \hline  & mm & & kg ha\({}^{-1}\) year\({}^{-1}\) & & \\ Bulk deposition & 1092 \(\pm\) 198 & 21 \(\pm\) 5.0 & 1.5 \(\pm\) 0.6 & 6.0 \(\pm\) 1.7 & 3.6 \(\pm\) 0.7 \\ Spruce & & & & & \\ \hline Throughfall & 761 \(\pm\) 181 & 80 \(\pm\) 13 & 4.1 \(\pm\) 0.3 & 6.7 \(\pm\) 0.5 & 6.8 \(\pm\) 0.4 \\ Beech & & & & & \\ \hline Throughfall & 750 \(\pm\) 104 & 36 \(\pm\) 5.0 & 1.5 \(\pm\) 0.9 & 8.4 \(\pm\) 2.3 & 6.4 \(\pm\) 0.8 \\ Stemflow & 148 \(\pm\) 31 & 11 \(\pm\) 1.5 & 0.6 \(\pm\) 0.2 & 0.8 \(\pm\) 0.1 & 0.5 \(\pm\) 0.1 \\ \hline \end{tabular}
\end{table} 
Table 4: Fluxes (\(\pm\)standard deviation) of water (mm), DOC and N (kg\(\cdot\)ha\({}^{-1}\cdot\)year\({}^{-1}\)) in bulk deposition, throughfall and beech stemflow for the period 2013–2015. \begin{table}
\begin{tabular}{c c c c c c} \hline
**2013–2015** & **H\({}_{2}\)O** & **DOC** & **DON** & **N-NH\({}_{4}\)** & **N-NO\({}_{3}\)** & **DOC/DON** \\ \hline  & mm & & kg ha\({}^{-1}\) year\({}^{-1}\) & & g\(\cdot\)g\({}^{-1}\) \\ Spruce stand & & & & & \\ \hline LFH & 336 \(\pm\) 96 & 179 \(\pm\) 59 & 5.6 \(\pm\) 1.7 & 0.34 \(\pm\) 0.13 & 0.58 \(\pm\) 0.18 & 32 \(\pm\) 0.59 \\
30 cm & 311 \(\pm\) 103 & 23 \(\pm\) 10 & 0.83 \(\pm\) 0.18 & 0.10 \(\pm\) 0.05 & 0.12 \(\pm\) 0.13 & 28 \(\pm\) 6.7 \\ Beech stand & & & & & \\ \hline LFH & 443 \(\pm\) 51 & 182 \(\pm\) 3.1 & 5.2 \(\pm\) 0.49 & 0.18 \(\pm\) 0.05 & 1.1 \(\pm\) 0.37 & 36 \(\pm\) 3.5 \\
30 cm & 314 \(\pm\) 44 & 18 \(\pm\) 5.0 & 0.63 \(\pm\) 0.16 & 0.70 \(\pm\) 1.1 & 1.2 \(\pm\) 1.0 & 28 \(\pm\) 1.5 \\ \hline \end{tabular}
\end{table} 
Table 5: Fluxes (\(\pm\)standard deviation) of water (mm), DOC, N (kg\(\cdot\)ha\({}^{-1}\cdot\)year\({}^{-1}\)) and mass ratio of DOC/DON in seepage water from the forest floor and mineral soil at the depth of 30 cm for the period 2013–2015.