Title
Euscaldian and south Aquitanian mixed oak forests (Quercus petraea, Quercus robur, partly Quercus pyrenaica, Sorbus torminalis) with Ilex aquifolium, Blechnum spicant, Pyrus cordata, Pulmonaria longifolia, Hypericum androsaemum
Geographical distribution
Country/territory
France: Pyrenean foreland: Béarn, western Armanac, Chalosse; Spain: Basque country, Cantabria
area frequency
17 polygons.
Scientific names of main plant communities and their most common synonyms (with author citation)
Hyperico pulchri-Quercetum roboris Rivas-Martínez, Báscones, Díaz, Fernández González & Loidi 1991 (syn.: Tamo communis-Quercetum roboris Rivas-Martínez, Díaz, F. Prieto, Loidi & Penas 1984).
Structural feature of the main community(ies) (layers, life-forms, etc.)
Three-layered closed mixed forests, dominated by Quercus petraea or Quercus robur, and partially by Fagus sylvatica. Tilia cordata and Quercus pyrenaica are companions. Castanea sativa is not rare, and in addition to Sorbus torminalis there is also Populus tremula occasionally. In the species-rich shrub layer that reveals a two-layered construction Corylus avellana dominates. The rich herb layer consists mainly of oligotrophic Quercetalia and heath species.
Dominant and most frequent species in different layers
Tree layer
Quercus robur, Quercus petraea, Quercus pyrenaica, Fagus sylvatica, Castanea sativa (introduced), Tilia cordata, Sorbus torminalis, Populus tremula
Shrub layer
Young growth of trees, Betula pendula, Ilex aquifolium, Pyrus cordata, Frangula alnus, Mespilus germanica, Corylus avellana, Crataegus monogyna; lower shrub layer: Ruscus aculeatus, Rosa arvensis, Rubus caesius, Rubus ulmifolius
Lianas
Hedera helix, Lonicera periclymenum, Tamus communis, Rubia peregrina (distinctively more rare)
Herb layer
Melampyrum pratense, Pteridium aquilinum, Solidago virgaurea, Agrostis capillaris, Viola riviniana, Deschampsia flexuosa, Veronica officinalis, Potentilla erecta, Potentilla montana, Potentilla sterilis, Holcus mollis, Teucrium scorodonia, Hedera helix, Lathyrus linifolius, Blechnum spicant, Luzula sylvatica, Luzula pilosa, Hypericum pulchrum, Hypericum androsaemum, Pulmonaria affinis, Pulmonaria longifolia, Pseudarrhenatherum longifolium, Daboecia cantabrica, Erica vagans, Erica arborea, rarely Vaccinium myrtillus, Athyrium filix-femina
Moss layer (incl. lichens)
Polytrichum formosum, Atrichum undulatum, Eurhynchium striatum, Eurhynchium praelongum, Plagiomnium undulatum, Isothecium myosuroides
Diagnostically important species
Quercus robur, Quercus pyrenaica; Ilex aquifolium, Pyrus cordata; Hypericum pulchrum, Hypericum androsaemum, Blechnum spicant, Tamus communis, Potentilla montana, Pulmonaria longifolia, Pulmonaria affinis
Ecological variants
One can distinguish between a moister form with Circaea lutetiana, Lysimachia nemorum, Carex remota, Blechnum spicant, Athyrium filix-femina and a drier form with Quercus pyrenaica on alluvial soils or sandy molasses. In Spain with regard to the Hyperico pulchri-Quercetum, the quercetosum roboris subassociation has been described as a typical form and the fagetosum sylvaticae subassociation has been described as typical for rain-rich valleys in submontane locations.
Geographical variants (geogr. differential species)
In France with stronger participation of Quercus petraea and additions of Mespilus germanica, Corylus avellana, Tamus communis; in Spain the unit is also characterised by Erica vagans, Daboecia cantabrica, and Potentilla montana etc..The beech is worthy of special mention. From the vegetation surveys of Comps (1975) it became clear that the beech, when approaching the Pyrenees, could dominate together with oaks at shady slopes of hills, and that it disappeared as soon as the annual precipitation fell below 800 mm.
Natural accompanying vegetation (most important units in complex with the name giving mapping unit, scientific names)
Mosaic consisting of different wet forest communities: willow scrub with Salix atrocinerea and Osmunda regalis; Carici laevigatae-Alnetum in river valleys originating in the Pyrenees.
Adjoining climax and permanent vegetation (with numbers of mapping units)
acidophilous oak and mixed oak forests (F7, F25), mixed oak-ash forests (F33), species-poor beech forests (F81, F98), species-rich beech forests (F136), mixed downy oak forests (G38), Quercus ilex subsp. rotundifolia-forests (J11), alluvial and moist forests (U9, U25).
Land use, substitute communities
forestry (substitute communities, plantations of economic tree-species, scrub)
Often exploited as low forest, sometimes with Pteridium aquilinum as degradation indicators. The species assemblage of the forests has sometimes been considerably altered by the planting of various exotic species: Pinus pinaster, Pinus radiata, Castanea sativa, Quercus rubra, Eucalyptus spp. scrub substitute communities: Frangulo alni-Pyretum cordati, Salici atrocinereae-Betuletum celtibericae, Ulici galli-Arbutetum unedonis, Ulici europaei-Cytisetum commutati.
grassland (meadows, pastures, herb-rich communities)
On molasses or sandy deposits heaths with Ulex minor, Ulex gallii, Erica vagans, Lobelia urens, Simethis planifolia, Scilla verna and Pseudarrhenatherum longifolium (e.g. Ulici galli-Ericetum ciliaris; Ulici europaei-Ericetum vagantis); these heaths (regional name "touya") are frequently interspersed with stunted forms of Quercus pyrenaica, and sometimes transformed by grazing (Lino biennis-Cynosuretum cristati) or mowing (haymaking) into grassland or have been degraded so much that they become dominated by Pteridium aquilinum stands. These heaths are endemic in the Euscaldian and Cantabrian regions.
arable land (characteristic weed communities)
Vineyards, tobacco, corn cultivation.
settlements (typical ruderal vegetation)
Urtico-Sambucetum ebuli.
Site conditions of the mapping unit
Landscape type, geomorphology
In the northern foothills of the Pyrenees and the Cantabrian mountains where the landscape is broken up into river valleys and long mountain ridges.
Altitudinal belt and/or altitudinal range
colline to submontane; 100-400 m
Geology (bedrock)
clayey-sandy molasse (Tertiary, Cretaceous), often covered by Pleistocene sands from the Pyrenees; sandy fluviatile sediments (Pleistocene, Holocene)
soil type, also the depth of fine textured earth (soil), stone content; (international nomenclature)
base-poor, acidic, partly gleyed brown soils and parabrown soils, weakly developed podzoles, locally stagnogleys; (dystric and gleyic cambisols; dystric planosols, leptic podzols)
soil texture
loamy to more clayey sand
soil moisture, water balance
fresh to moderately dry, locally stagnating moist
soil reaction
strongly to moderately acidic
soil fertility
oligotrophic, oligo-mesotrophic
Climate incl. local climate
climate type (following Walter & Lieth)
V1, V(IV)1
average annual temperature
12-14 EC
average annual precipitation
900-1600 mm
average temperature of the warmest month
July 20-22 EC
average temperature of the coldest month
January 6-7 EC
local climate or other climatic peculiarities
Moderately warm-humid climate.
Importance for nature protection
Present state and development trend of natural vegetation (degree of endangerment)
Often managed as low forest, sometimes degraded to heaths or transformed into coniferous or deciduous plantations, semi-natural stands are now only preserved as remnants.
endangered communities, species worthy of protection in natural vegetation
No details
causes of endangerment
Low forest use, agricultural use (pastures, crop fields), afforestation with exotic tree species.
required measures for protection and restitution
Preservation of semi-natural remnants, restoration through plantation of indigenous tree species, reduction of introduced tree species.
Localities of representative stands (loci typici) with state of protection
of the natural vegetation
No details
of characteristic substitute communities worthy of protection
No details
Most important references (author, year)
Braun-Blanquet 1967a; Braun-Blanquet 1967b; Comps 1972; Izard, Dupont & Lascombes 1968; Jovet & Dupias 1969; Loidi Arregui, Biurrun Galarraga & Herrera Gallastegui 1997; Loidi Arregui, Díaz González & Herrera Gallastegui 1997; Peinado Lorca & Rivas-Martínez (Ed.) 1987; Rameau 1996b; Rivas-Martínez 1987; Rivas-Martínez, Bascones, Díaz González, Fernández-González & Loidi Arregui 1991a; Rivas-Martínez, Bascones, Díaz González, Fernández-González & Loidi Arregui 1991b; Rivas-Martínez, Díaz González, Fernández Prieto, Loidi Arregui & Penas Merino 1984; Rivas-Martínez, Loidi Arregui, Cantó, Sancho & Sánchez-Mata 1985
Compiled by
Contributions by A. Noirfalise; A. Penas Merino and L. Herrero Cembranos; J. Loidi; Completion by C. Hettwer based on documents by J.C. Rameau; revised by J.R. Cross, J. Pallas, U. Bohn
