Table 1.
Concentrations of nutrients (N, P, K, Ca, and Mg) in the leaves and needles of pubescent oak, holm oak, Aleppo pine and black pine for defoliated and undefoliated trees. Results are expressed as mean values (n = 3). Values marked in bold show a statistically significant difference between defoliated and undefoliated trees for the same species according to the Student’s t-test (* p < 0.05). The colors indicate the concentrations of the elements: red—high; green—optimal; yellow—low [38].
| Species | Category | N | P | K | Ca | Mg |
|---|---|---|---|---|---|---|
| mg g−1 | mg g−1 | mg g−1 | mg g−1 | mg g−1 | ||
| Pubescent oak | Undefoliated trees (≤25%) | 16.95 | 1.22 | 6.62 | 10.72 | 1.23 |
| Defoliated trees (>25%) | 16.95 | 1.75 * | 7.50 * | 14.66 * | 1.97 * | |
| Holm oak | Undefoliated trees (≤25%) | 13.30 | 0.99 | 6.26 * | 6.21 | 1.22 |
| Defoliated trees (>25%) | 12.15 | 0.99 | 3.17 | 6.72 | 1.42 | |
| Aleppo pine | Undefoliated trees (≤25%) | 11.14 | 1.34 | 3.99 | 8.41 * | 1.65 |
| Defoliated trees (>25%) | 10.88 | 1.33 | 3.96 | 4.03 | 1.70 | |
| Black pine | Undefoliated trees (≤25%) | 10.11 | 1.20 | 4.98 | 5.24 * | 1.30 |
| Defoliated trees (>25%) | 9.69 | 1.51 * | 6.36 * | 2.52 | 1.22 |