Table 1 Geographical, topographical, climatic and ecological characteristics of the five P. nigra study sites including the meteorological stations used to obtain local climate data (codes are indicated between parentheses)

Latitude (N)

35° 15′

36° 58′

37° 22′

37° 39′

37° 43′

Longitude (W)

5° 15′

3° 52′

2° 50′

2° 05′

3° 28′

Elevation range (m)

1,700–2,000

1,500–1,600

1,800–1,900

1,700–1,900

1,600–1,900

Aspect

NW

N

N–NE

W

S–SE

Slope (%)

25

30

32

25

30

Diameter at 1.3 m (cm)

62.3 ± 8.9

55.40 ± 8.10

76.31 ± 5.13

60.24 ± 4.25

80.75 ± 4.67

Height (m)

9.2 ± 0.5

10.0 ±0.5

8.5 ± 0.2

9.1 ± 0.6

11.7 ±1.0

Age at 1.3 m (years)

243 ± 22

268 ± 56

215 ± 10

160 ± 19

231 ± 16

Meteorological station (latitude N, longitude W, elevation in m)

Chefchaouen (35° 10′, 5° 18′, 630)

Fornes (36° 57′, 3° 49′, 900)

Bacares (37° 15′, 2° 27′, 1200)

María (37° 42′, 2° 09′, 1197)

Jimena (37° 50′, 3° 28′, 609)

Mean annual temperature (°C)

15.0

14.7

14.9

14.8

14.5

Mean temperature of the coldest–warmest months (°C)

8.8–22.9

6.7–24.2

7.5–24.5

6.8–24.4

6.5–23.7

Total annual precipitation (mm)

629

392

316

366

417

Precipitation of the driest–wettest months (mm)

5–96

4–53

5–38

8–44

6–54

Annual water balance (mm)

−150

−350

−470

−435

−320

Water balance of the driest–wettest months (mm)

−121–71

−130–33

−136–15

−133–23

−128–35