Title
Mixed downy oak forests (Quercus pubescens, Quercus petraea, Quercus robur) of the Gascogne, partly with Carpinus betulus, with Arum italicum, Pulmonaria affinis
Geographical distribution
Country/territory
France: Armagnac between Garonne/Tarn and the pre-Pyrenees
area frequency
4 polygons.
Scientific names of main plant communities and their most common synonyms (with author citation)
Viburno lantanae-Quercetum Lapraz 1963 and other communities.
Structural feature of the main community(ies) (layers, life-forms, etc.)
Three-layered, moderately-high forests with many thermophilous and mesophilous species.
Dominant and most frequent species in different layers
Tree layer
predominately Quercus pubescens, admixed Quercus petraea, Quercus robur, Prunus avium, Acer campestre, Acer monspessulanum, Sorbus domestica, Ulmus minor
Shrub layer
Viburnum lantana, Ligustrum vulgare, Lonicera xylosteum, Corylus avellana, Cornus sanguinea, Crataegus monogyna, Prunus spinosa, Pyrus cordata, Juniperus communis, Ruscus aculeatus, Daphne laureola
Lianas
Hedera helix, Lonicera periclymenum, Lonicera etrusca, Tamus communis, Rubia peregrina, (less often Clematis vitalba)
Herb layer
Arum italicum, Vincetoxicum hirundinaria, Carex flacca, Pulmonaria affinis, Brachypodium pinnatum, Hypericum hirsutum, Fragaria vesca, Teucrium chamaedrys, Teucrium pyrenaicum, Rubus caesius, Helleborus viridis subsp. occidentalis, Carex sylvatica, Carex umbrosa, Sanicula europaea, Viola reichenbachiana among others
Moss layer (incl. lichens)
No details
Diagnostically important species
Quercus pubescens, Quercus petraea, Quercus robur; Pyrus cordata, Daphne laureola, Lonicera etrusca; Arum italicum, Pulmonaria affinis, Teucrium pyrenaicum, Tamus communis
Ecological variants
No details
Geographical variants (geogr. differential species)
According to the distribution of Carpinus betulus, two different geographic strains can be differentiated: a western one where it is absent, and an eastern one where it occurs. The two strains are separated by the course of the Baise which flows crossways through Armagnac and also represents the eastern limit of Quercus pyrenaica in the Aquitanian basin.When one approaches the Pyrenees, the beech becomes a component of the tree layer above 300 m and can dominate even at the shaded slopes of the valleys. These beech mixed forests were assigned by Comps in 1972. They are characterised by Symphytum tuberosum; Luzula sylvatica, Euphorbia dulcis, Pulmonaria angustifolia, Milium effusum, Galium odoratum and Melica uniflora.
Natural accompanying vegetation (most important units in complex with the name giving mapping unit, scientific names)
Brookside forests with Populus alba, Fraxinus angustifolia subsp. angustifolia and Ulmus minor; oak-ash hornbeam forests on valley terraces, beech forests at higher locations and on shaded slopes.
Adjoining climax and permanent vegetation (with numbers of mapping units)
acidophilous oak forests (F7, F15), oak-hornbeam forests (F36), species-poor and species-rich beech- and mixed beech forests (F81, F82, F137), downy oak forests (G41, G42), holm oak forests (J14, J15), alluvial and moist forests (U8, U25).
Land use, substitute communities
forestry (substitute communities, plantations of economic tree-species, scrub)
The current area occupied by forest is very small; scrub consisting of Buxus sempervirens, Spartium junceum, Juniperus communis, Echinospartum horridum and usually Prunus spinosa, Crataegus spp. and Rosa canina.
grassland (meadows, pastures, herb-rich communities)
Calcareous short-grass meadows with Brachypodium pinnatum, Koeleria vallesiana, Globularia punctata, Dorycnium hirsutum, Teucrium chamaedrys, Teucrium pyrenaicum and numerous orchids.
arable land (characteristic weed communities)
Cereal cultivation: wheat, maize, sorghum and oil-producing crops, particularly sunflowers.
settlements (typical ruderal vegetation)
No details
Site conditions of the mapping unit
Landscape type, geomorphology
Flats of the Garonne and their numerous tributaries arising from the Pyrenees that cut the landscape into longitudinal chains of hills.
Altitudinal belt and/or altitudinal range
colline-submontane; 100-300 (to 500 m) at the foot of the Pyrenees (Bigome, Comminges, Ariège)
Geology (bedrock)
fluviolimnic Miocene (west of Garonne) as well as Miocene and Oligocene (east of Garonne) sediment rocks (Tertiary) originating from the Pyrenees
soil type, also the depth of fine textured earth (soil), stone content; (international nomenclature)
lime-rich brown soils and rendzines; (calcic and eutric cambisols; rendzic leptosols)
soil moisture, water balance
fresh to moderately dry
soil reaction
weakly acidic to neutral
soil fertility
meso-eutrophic
Climate incl. local climate
climate type (following Walter & Lieth)
V(IV)1
average annual temperature
12-13 °C
average annual precipitation
600-700 mm
average temperature of the warmest month
July 20-21 °C
average temperature of the coldest month
January 4-6 °C
local climate or other climatic peculiarities
---
Importance for nature protection
Present state and development trend of natural vegetation (degree of endangerment)
The forest stands are more or less degraded low forests. It is not certain whether semi-natural relict stands are still present due to the long-standing agricultural use that dates back to ancient times.
endangered communities, species worthy of protection in natural vegetation
No details
causes of endangerment
Timber harvesting, low forest management.
required measures for protection and restitution
Regeneration of semi-natural forests from suitable low forest stands.
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)
Comps 1972; Gaussen & Rey 1947; Rey 1963; Rameau 1997
Compiled by
A. Noirfalise completed by C. Hettwer based on documents by J.-C. Rameau
