W9 - Fraxinus Excelsior-Sorbus Aucuparia-Mercurialis Perennis Woodland

Summary

Synonymy

Upland ashwood Tansley 1939; Corylo-Fraxinetum Br.-Bl. & Tx 1952 p.p.; Herb-rich birchwood Pigott 1956a p.p.; Fraxinus-Brachypodium sylvaticum nodum McVean & Ratcliffe 1962; Corylus scrub McVean & Ratcliffe 1962; Mixed deciduous woodland McVean & Ratcliffe 1962; Be/w/a-herb nodum, basiphilous facies McVean & Ratcliffe 1962; Ashwood McVean 1964; Dryopterido-Fraxinetum blechnetosum Klötzli 1970; Sorbo-Br achypodie turn Graham 1971; Fraxinus excelsior-Brachypodium sylvaticum Association Birks 1973; Corylus avellana-Oxalis acetosella Association Birks 1973 p.p.; Betula pubescens-Cirsium heterophyllum Association Birks 1973; Mixed Deciduous Woodland Ferreira 1978 p.p.; Ashwych elm stand types lAb & ID Peterken 1981 p.p.; Hazel-ash stand type 3C Peterken 1981 p.p.; Alder stand type 7D Peterken 1981 p.p.; Birch stand type 12B Peterken 1981 p.p.; Primulo-Quercetum J. Tüxen apud Birse 1982 p.p.; Querco-Ulmetum glabrae Birse & Robertson 1976 emend. Birse 1984 p.p.

Constant species

Fraxinus excelsior, Corylus avellana, Dryopteris filixmas, Mercurialis perennis, Oxalis acetosella, Viola riviniana, Eurhynchium praelongum, E. striatum, Plagiomnium undulatum, Thuidium tamariscinum.

Rare species

Actaea spicata, Bromus benekenii, Crépis mollis, Gagea lutea, Polygonatum verticillatum.

Physiognomy

In the Fraxinus-Sorbus-Mercurialis woodland, as in its southern lowland counterpart, the Fraxinus-Acer-Mercurialis woodland, Fraxinus excelsior and Corylus avellana play a major role in the definition of the canopy. Both species are constant here and frequently abundant, often dominating the woody cover in various proportions. Typically, though, trees and shrubs with more continental affinities are very scarce. Tilia cordata survives on some Lake District crags in association with the community (Pigott & Huntley 1978), some Cumbrian, Pennine and southern Scottish stands provide northerly localities for Acer campestre, Rhamnus catharticus or Euonymus europaeus (Ratcliffe 1977) and Viburnum opulus extends further north in the more oceanic parts of north-west Scotland (Birks 1973, Ratcliffe 1977) but, for the most part, this kind of woodland lies beyond the north-western limit of these species.

By contrast, birch, almost always Betula pubescens on the moist soils characteristic of this woodland and increasingly to the north ssp. carpatica, and Sorbus aucuparia are much more frequent than in most Fraxinus-Acer-Mercurialis woodlands. B. pubescens is the more common and generally the more abundant but S. aucuparia can be locally prominent, especially in ungrazed stands (McVean 1964a) and quite commonly the two co-dominate with Fraxinus and Corylus.