Tree Lungwort.
ASH WOODLAND
Ash is a widespread tree in Britain, often growing alongside oaks and other deciduous species. However, in some circumstances it comes to dominate certain woodlands. It thrives if soil conditions suit it – it favours basic soils, and can tolerate occasionally waterlogged conditions, but will also grow on limestone pavements.
In lowland Britain in particular, Ash has often been deliberately encouraged and managed as a source of excellent timber. Traditionally, it was coppiced regularly to produce tall, straight poles and in some woods huge stools have developed that are hundreds of years old. Hazel coppice is often grown as an understorey beneath its larger cousin.
Ancient stools of Ash produce a succession of tall, straight poles if coppiced periodically and managed correctly.
Woodland flowers are very much a feature of traditionally managed Ash woods. Bluebell, Lesser Celandine, Dog’s Mercury and Wood Anemone are often common, with star attractions being Herb-Paris, Goldilocks Buttercup and Early-purple Orchid.
Upland limestone pavement is perhaps a surprising place to find Ash, given its tolerance of, and seeming predilection for, damp ground in other locations. Nevertheless, thrive it does, often accompanied by Bird Cherry and Rowan.
BEECH WOODLAND
Few trees are more successful at eliminating competition from rival species than Beech, and in mature woodland it often forms such a dense canopy that competition from other tree species is essentially eliminated. Beech will tolerate a wide range of soil types, from fairly acid to calcareous. It is arguably at its finest growing on the latter, especially when covering the slopes of chalk downs. Beech woodlands in such settings have the fitting name of ‘hangers’.
Dark and gloomy during the summer months, by contrast a Beech woodland in winter is light and airy, with colour provided by the fallen leaves.
During the summer months very little light penetrates to the woodland floor. Low light levels, combined with the dense carpet of fallen leaves that covers the ground, ensures that few woodland flowers are able to survive. Those that do are restricted mainly to clearings and rides, and in such places Sanicle, Woodruff and a number of helleborines can sometimes be found. A small group of specialist plants do grow in the deep shade of Beech woodlands: species such as the Bird’s-nest Orchid and Yellow Bird’s-nest lack chlorophyll and cannot photosynthesise, relying on a saprophytic way of life for nutrition.
For many people, Beech woods are at their best in the autumn, not only because of the stunning foliage colours but also because of the intriguing range and abundance (in wet years) of fungi. Many of these are entirely restricted to Beech woodlands and some of the associated Russula and Boletus species are extremely colourful themselves.
The Devil’s Bolete is a rare and spectacular fungus that grows beneath ancient Beech trees on chalky soil.
Although it is seen only irregularly, the Ghost Orchid is the Holy Grail for British botanists. Scouring ancient Beech woods in central England represents a naturalist’s only realistic prospect of finding one in this country.
BIRCH WOODLAND
Birches are often viewed with disdain and dismissed as being little more than scrub trees. It is true that, in certain circumstances, Silver Birch, in particular, is an aggressively invasive species of heathland and newly cleared woodland on neutral to acid soils. However, in its favour is the fact that it plays host to a wide range of insects, in particular the larvae of many moth species. Most feed on birch leaves but the larva of the Large Red-belted Clearwing Synanthedon culiciformis feeds on wood, sometimes being discovered in cut stumps.
In the autumn, Silver Birches usually turn a spectacular golden yellow for a week or two. Around the same time, an amazing array of fungi put in an appearance as well, many of them only found growing in association with these trees. The best-known fungal association with Silver Birch is probably the Fly Agaric Amanita muscaria, an unmistakable and striking species. But dozens of other species are invariably associated with these trees, including several Boletus and Russula species as well as the Birch Polypore Piptoporus betulinus.
Silver Birches provide stunning autumn colours that lift the spirits.
Phil Green
The larvae of the Large Red-belted Clearwing feed beneath birch bark and the secretive, day-flying adults are sometimes spotted resting among the foliage.
The Buff-tip has an uncanny resemblance to a snapped birch twig: a convincing camouflage that increases the moth’s chances of avoiding detection by predators.
The Fly Agaric has a mycorrhizal association with the roots of birch trees (see p.), so you are unlikely to find this fungus growing anywhere else.
Downy Birch often grows alongside Silver Birch but comes to replace it in many western, northern and upland parts of the region. In terms of specifically associated wildlife, it has much in common with Silver Birch, particularly when it comes to fungi. However, in Scotland, in particular, superficially similar hardy Highland species often replace their southern counterparts. Look out for the intriguing Hoof Fungus Fomes fomentarius growing on stumps and trunks.
CARR WOODLAND
Nature is dynamic, and there is a general trend in all environments for newly created habitats to become colonised by increasingly more stable plant communities. In most locations this progression follows a predictable route and the process itself is referred to as habitat succession.
The impact of succession in wetland habitats is particularly striking. Marginal vegetation soon encroaches upon areas of open water, and silt builds up, gradually reducing water levels. Reeds, bulrushes, sedges and rushes then take hold and open water soon gives way to tussocky ground. The resulting mire is referred to as a fen if the water is neutral to basic or a bog if the ground is acidic. Trees soon begin to appear and those tolerant of waterlogged ground – Alder and various willow species – give rise to a woodland community called carr where once a fen prevailed. Carr is the penultimate stage in the process of succession, which leads eventually to the formation of dry land and a climax community of Oak and Ash.
Carr woodland is not the easiest of plant communities to explore and, unless the area in question is a boardwalked nature reserve, wet feet are inevitable. However, such areas are usually botanically rewarding. Insect life usually abounds too, particularly in the form of midges and mosquitoes.