ONLINE RESOURCE 1. Study areas: each species study area is a selected Region of Provenance. (a) Map of Continental Spain with the location of selected RP. RP areas are surrounded by a line and forest stands are indicated with a grey area. See Table 1 for species abbreviation. (b) Table with species and the chosen RP (number and name).

Species / Region of Provenance
Pinus halepensis / 14. Bética Spetentrional
Pinus nigra / 7. Sistema Ibérico Meridional
Pinus pinaster / 8. Meseta Castellana
Pinus pinea / 1. Meseta Norte
Pinus sylvestris / 7. Prepirineo Catalán
Pinus uncinata / 1. Pirineo Central
Fagus sylvatica / 17. Sistema Ibérico
Quercus faginea / 2. Pirineos
Quercus ilex / 11. Región Extremadurense
Quercus petraea / 9. Pirineo Oriental
Quercus pyrenaica / 4. Cordillera Cantábrica Meridional
Quercus robur / 1. Galicia
Quercus suber / 5. Siera Morena Occidental

ONLINE RESOURCE 2. Wood density, shade tolerance and climatic variables (rainfall, drought, frost) of 13 Iberian tree species. Climatic variables were determined for each species in the area where it attained its maximum abundance and where the trees were measured (see Appendix A).

Species / Wood density a / Shade tolerance b / Rainfall e / Drought f / Frost h
Class c / Index d
Pinus halepensis / 470 / Half shade / 1.35 / 410 / 4.0 / 0.1
Pinus nigra / 510 / Half light to half shade / 2.10 / 700 / 1.8 / 3.3
Pinus pinaster / 475 / Half light to light / 1.35* / 473 / 3.0 / 2.5
Pinus pinea / 590 / Light / 1.35* / 440 / 3.2 / 2.3
Pinus sylvestris / 500 / Light / 1.67 / 935 / 0.0 / 3.3
Pinus uncinata / 500 / Light / 1.89* / 1281 / 0.0 / 6.2
Fagus sylvatica / 692 / shade / 4.56 / 901 / 0.2 / 3.6
Quercus faginea / 790 / Half light / 2.35* / 836 / 0.7 / 2.5
Quercus ilex / 960 / Half light / 3.02 / 635 / 3.9 / 0.0
Quercus petraea / 670 / Half light / 2.73 / 1006 / 0.1 / 2.6
Quercus pyrenaica / 750 / Half light / 2.24 / 935 / 1.2 / 3.8
Quercus robur / 670 / Light / 2.45 / 1375 / 0.7 / 0.1
Quercus suber / 1000 / Half shade / 2.35* / 721 / 3.8 / 0.0

a Units: kg/m; referred to a moisture content of 12% (Guindeo et al., 1997)

b Capacity to grow under low light levels.

c Shade tolerance classification (Serrada et al., 2008)

d Shade tolerance index (Niinements and Valladares, 2006). * This value was interpolated using class and index .

e Mean annual precipitation in mm

f Months when the monthly precipitation [in mm] is less than twice the average monthly temperature [in ºC]

g Mean annual temperature in ºC

h Months when the minimum average temperature of the month is equal or below 0 ºC