## 3 Results
### The Effect of Damaging Factors on the Composition and Structure of Pine Stands on Degraded Lands
#### 3.2.1 The Compositional Diversity of Pine Stands
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**EP-RP Species**} & \multicolumn{8}{c}{**Statistical Parameters**} \\ \cline{2-13}  & \multicolumn{4}{c}{**Basal Diameter (cm)**} & \multicolumn{8}{c}{**Total Height (m)**} \\ \cline{2-13}  & \(\bar{\mathbf{d}}\) & **Median** & **s** & **cv (\%)** & **Min** & **Max** & \(\bar{\mathbf{h}}\) & **Median** & **s** & **cv (\%)** & **Min** & **Max** \\ \hline
**3–4 total** & **21.70** & **23.30** & **8.07** & **37.22** & **7** & **37** & **16.34** & **17.90** & **4.64** & **28.43** & **6** & **24** \\ \hline Pi & 24.05 & 26.15 & 7.22 & 30.02 & 8 & 37 & 17.51 & 18.75 & 3.99 & 22.81 & 8 & 24 \\ \hline Pi.n & 17.82 & 17.85 & 7.59 & 42.63 & 8 & 29 & 14.68 & 15.70 & 4.73 & 32.23 & 7 & 22 \\ \hline
**3–9 total** & **22.39** & **23.25** & **7.72** & **34.49** & **8** & **38** & **17.08** & **19.05** & **5.54** & **32.46** & **5** & **28** \\ \hline Ar.t & 12.95 & 13.00 & 5.01 & 38.67 & 8 & 22 & 8.80 & 7.10 & 4.88 & 55.49 & 5 & 19 \\ \hline Ci & 14.40 & 14.40 & 5.94 & 41.25 & 10 & 19 & 12.35 & 12.35 & 4.45 & 36.07 & 9 & 16 \\ \hline Pi & 27.80 & 28.40 & 4.14 & 14.90 & 22 & 32 & 19.75 & 20.05 & 1.96 & 9.96 & 17 & 22 \\ \hline Pi.n & 24.73 & 25.10 & 6.05 & 24.49 & 12 & 38 & 19.04 & 19.70 & 3.82 & 20.06 & 6 & 28 \\ \hline
**3–10 total** & **26.72** & **27.80** & **6.15** & **23.05** & **9** & **35** & **18.79** & **20.40** & **4.97** & **26.49** & **6** & **25** \\ \hline Pi & 28.67 & 28.45 & 3.59 & 12.55 & 21 & 35 & 20.46 & 20.55 & 2.68 & 13.10 & 13 & 25 \\ \hline Ar.t & 15.67 & 14.90 & 2.94 & 18.76 & 13 & 20 & 8.52 & 8.30 & 1.23 & 14.47 & 7 & 10 \\
**2–1 total** & **22.99** & **23.10** & **6.20** & **27.00** & **9** & **35** & **16.23** & **16.70** & **3.87** & **23.90** & **8** & **23** \\ \hline Mj & 16.32 & 17.00 & 5.25 & 32.20 & 9 & 23 & 9.22 & 9.30 & 1.08 & 11.74 & 8 & 11 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: General statistic parameters for diameter and height in pine stands with ages between 55 and 65 years. Figure 11: The composition of pine stands studied in EP3: (**a**) RP9 and (**b**) RP10. In the case where more species have appeared naturally in the experimental plots under the influence of abiotic factors, we can see a bilayer tendency, as shown in Figures 12a,b and 13a,b. The determination coefficients (R\({}^{2}\)) express a close correlation between diameter and height. We were able to adjust the experimental values after a logarithmic regression equation: \(y=a\cdot log(x)-b\), where \(y\) is height; x is basal diameter; a and b are the regression equation coefficients. The same model for both species is not comprehensive because their behavior in different even in the same environmental conditions (Figures 12a and 13a). A very strong correlation between total height (h) and basal diameter (DBH) was found for both species: R\({}^{2}\) = 0.8683 for Scots pine, and R\({}^{2}\) is between 0.4946 and 0.9038 for European black pine (Figure 13a,b). \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{3}{*}{
\begin{tabular}{c} **EP-RP** \\ **Species** \\ \end{tabular} } & \multicolumn{8}{c}{**Statistical Parameters**} \\ \cline{2-13}  & \multicolumn{8}{c}{** Basal Diameter (cm)**} & \multicolumn{8}{c}{**Total Height (m)**} \\ \cline{2-13}  & \(\mathbf{\hat{d}}\) & **Median** & **s** & **cv (\%)** & **Min** & **Max** & \(\mathbf{\hat{h}}\) & **Median** & **s** & **cv (\%)** & **Min** & **Max** \\ \hline Pi & 24.41 & 25.45 & 5.02 & 20.59 & 15 & 32 & 17.14 & 17.65 & 3.93 & 22.95 & 8 & 23 \\ \hline Pi.n & 23.81 & 23.10 & 6.03 & 25.34 & 13 & 35 & 17.04 & 16.80 & 2.53 & 14.87 & 12 & 22 \\ \hline
**2-9 total** & **25.65** & **25.10** & **6.33** & **24.67** & **13** & **41** & **20.06** & **20.90** & **3.23** & **16.12** & **10** & **29** \\ \hline Pi & 31.63 & 31.40 & 1.65 & 5.24 & 30 & 35 & 22.63 & 23.25 & 2.47 & 10.95 & 18 & 25 \\ \hline Pi.n & 25.44 & 25.10 & 6.25 & 24.56 & 13 & 41 & 19.98 & 20.80 & 3.18 & 15.95 & 10 & 29 \\ \hline \hline \end{tabular}
\end{table}