a beech tree (Fagus
canopy. Beech trees tend to produce such a complete canopy that
the herb and shrub layers are reduced to a minimum in beech
woods. In some places the shade is so dense that no vegetation
occurs at all: the forest floor being covered with rotting beech
leaves. Nevertheless, beechwoods can host a rich variety of
orchids, particularly as they preferentially grow on calcareous
limestone soils which are preferred by many orchids.
Shade-tolerant orchids, such as the White helleborine (Cephalanthera
damasonium), Bird's Nest Orchid (Neottia nidus-avis),
Narrow-Lipped Helleborine (Epipactis leptochila), Common
Twayblade (Neottia ovata) and Violet Helleborine (Epipactis
purpurata) occur here. The Violet Helleborine is
p[articularly shade tolerant and may grow in the darker parts of
beechwoods where little else can grow. In contrast, Broad-Leaved
Helleborine (Epipactis helleborine) which also grows in
beechwoods, prefers more light and so is more typically found in
glades, along track-ways and along the fringes of the woods,
sometimes among scrub.
Above: the canopy of an oak tree. Oak trees allow enough light to pass through their canopies to allow a rich diversity of shrubs and herbs to flourish beneath.Oaks often form mixed woodland with ash trees (Fraxinus excelsior) and other large deciduous trees, whilst smaller trees such as Hazel (Corylus avellana), Crab Apple (Malus sylvestris) form a lower layer, often reduced to shrubs if coppiced. Silver Birch (Betula pendula) and Downy Birch (Betula pubescens) which are relatively fast growing and short-lived trees may spring up whenever an opening appears in the canopy, such as due to tree fall, but are eventually replaced by oak or ash trees.
updated: 19 May 2019.