T1Bx Mixed forests on acid soils

Description

Acidophilous zonal forests in the lowlands of the northern, maritime territories of the ecoregion, where summer-droughts are rare and mild, soils remaining moist enough for deciduous broadleaved trees to support the high transpiration rates of their competitive light-capturing apparatus. Usually dominated by pedunculate oak, but with a pretty diverse tree layer including sweet chestnut, birch, ash and wild cherry.

Protection

Managed stands rich in sweet chestnut are protected by the EU Habitat Directive under the code 9260 ("Castanea sativa woods").

Phytosociology i

• Blechno spicant-Quercetum roboris
• Hyperico pulchri-Quercetum roboris
• Lonicero periclymeni-Quercetum pyrenaicae
• Rusco aculeati-Quercetum roboris
• Vaccinio myrtilli-Quercetum roboris
• Viburno tini-Quercetum roboris

Relations with other habitat types

A new regional level IV unit is created, since the fusion of this acidophilous analogue of T1E1 with the montane forests of T1By is, for deep floristic and ecological reasons, quite unsatisfactory at that level. In the lowest areas, where severe frosts and snowfalls are a rare occurrence, they may transition towards T22x. At somewhat higher elevations or in particularly well-oriented valleys, rainier and cooler summers reduce even further the risk and severity of droughts and lead to the predominance of T182. In southern Galician and northern Portuguese coastal areas, on their part, sunny and dry summers lead to somewhat complex transitions towards T211. A number of higher level units recognised by EUNIS intend to capture all these transitions: T1B621 ("Eastern Cantabrian acidophilous oak forests"); T1B622 ("Western Cantabrian acidophilous oak forests"); T1B631 ("Mesophile Luso-Galician collinar oak forests"); T1B632 ("Humid Luso-Galician collinar oak forests"); T1B64 ("Luso-Galician montane acidophilous oak forests"). Traditional, centuries-old management has often transformed these communities into chestnut-enriched woodlands exploited for timber or fruit.