## 3 Results
### The Effect of Damaging Factors on the Composition and Structure of Pine Stands on Degraded Lands
#### 3.2.2 Analyzing the Stability of Scots Pine and Black Pine Stands
The low-vulnerability domain is represented by a proportion of 37.89% from the total number of Scots pine trees, with a mean basal diameter (\(\overline{d}\)) of 32.39 \(\pm\) 3.94 cm, which corresponds to a mean height (\(\overline{h}\)) of 22.53 \(\pm\) 2.93 m (RP6). The high-vulnerability domain is represented by a proportion of 9.47% from the total number of Scots pine trees, with a mean basal diameter (\(\overline{d}\)) of 21.17 \(\pm\) 1.50 cm, which corresponds to a mean height (\(\overline{h}\)) of 24.00 \(\pm\) 2.05 m (RP6). _In stands of pure black pine (RP9)_, the low-vulnerability domain is the most representative one, with a proportion of 57.58% from the total number of black pine trees, with a mean basal diameter (\(\overline{d}\)) of 29.28 \(\pm\) 4.17 cm corresponding to a mean height (\(\overline{h}\)) of 19.95 \(\pm\) 3.24 m (EP4 and RP9). The moderate-vulnerability domain is represented by a proportion of 36.36% from the total number of black pine trees, with a mean basal diameter (\(\overline{d}\)) of 22.42 \(\pm\) 2.91 cm corresponding to a mean height (\(\overline{h}\)) of 20.28 \(\pm\) 2.75 m (RP9). The high-vulnerability domain is represented by a proportion of 6.06% from the total number of black pine trees, with a mean basal diameter (\(\overline{d}\)) of 21.58 \(\pm\) 0.75 cm corresponding to a mean height (\(\overline{h}\)) of 27.33 \(\pm\) 4.53 m (RP9). Pine Stands with Ages of 45 Years (RP5 and RP9-EP1)  
The average slenderness index for pine species from the stands' compositions indicates a high vulnerability towards wind and snow. The high-vulnerability domain (I! 1.00) ranges between the averages of 17.07% (RP5 and EP1) and 29.82% (RP9 and EP1) for the Scots pine species, respectively, and between 17.14% (RP9 and EP1) and 31.58% (RP5 and EP1) for the black pine. The moderate-vulnerability domain (I between 0.80 and 1.00), with an average interval between 40.00 and 65.85% (RP8, Pi) for the total number of trees, represents the highest percentage occupied by pine trees. For the domain with a low vulnerability (I! 0.80), the average ranges are between 12.28 and 42.86% of N, with the maximum of viable trees obtained from RP9 (Figure 20a,b). The framing within the moderate- and high-vulnerability domains is produced at a value lower than 16 cm in basal diameter compared with the value of the basal diameter of the basal area (\(\overline{\text{dg}}\)). The structure of younger stands (45 years), with a larger number of trees per hectare and with a higher consistency (over 0.80), determines the predisposition towards crown or stalk breaks, tiltings and treefalls, as well as interior wood damages. Under a statistical report (Table 7), we analyzed the four cases between which the means and variances were compared for the two populations with different ages but originating from the same phytoclimatic storey. Compared with the harmful abiotic factors (wind, snow, etc. ), at different ages, the difference between the means and variances of slenderness index (I) do not differentiate intraspecifically or interspecifically for both Scots pine and black pine species in moderate- and high-vulnerability domains. However, it was found that the differences between the means and variances are significant in the low-vulnerability domain only in black pine stands, with a coverage percentage probability of 95%.