This is the first of a series of articles that look at the natural habitats in the UK, beginning with a personal favourite – Ancient Woodland.
The term, Ancient woodlands has varied meanings depending on where you are.
Ancient woodlands are defined as woodlands that have been permanently wooded since 1600 in England and Wales and after 1750 in Scotland. Ancient woodland now covers just 2.5% of the UK forest, making it a rare and endangered habitat.
To determine if woodland is Ancient, you could research local maps and records or, as I prefer, look at what is growing. Ancient woodlands usually have an abundance of plants that spread slowly over the ground, such as wood anemone, wood sorrel and ransoms (wild garlic), and those whose seeds fall close to the parent, for example, the wild service tree. These plants, along with guelder rose, wood spurge and small-leaved lime, are some of the most likely indicators that the woodland is ancient.
One thing we can be sure of is that Ancient woodland has been around for centuries and has developed unique communities of plants and animals, many of which aren’t found in any other habitat.
Ancient woodland is the richest and most biodiverse terrestrial habitat in the UK. It is home to more threatened species than any other habitat. To qualify as ancient woods, they must contain woody stems that are at least sixty years old.
On a microscopic level, the soil in ancient woodlands has layers of humus, broken-down matter. The mycelium of different fungi lives in this soil and also in the woody stems of tree trunks and branches, called lignin.
Ancient woodland is home to large populations of invertebrates (insects, snails, worms, etc.) that recycle forest debris into the richest organic humus. This organic material’s presence gives ancient woodland its wonderful sweet smell.
As animals roam, forage and defecate through the forest, their waste is added to the organic debris, which provides nutrients for all living things in the forest.
Ancient woods may have been settled for over 6,000 years and will be home to specialist species of insects, birds and mammals found nowhere else on Earth.
The fungi growing in their ground make them important to humans because they provide us with food and medicine.
So let’s look at what makes an Ancient woodland so distinctive.
Every woodland, ancient or not, is unique and as individual as you and me. Its DNA is based on the soil structure, the plant species that can thrive, and the wildlife it attracts.
Woodlands were very important to our ancestors; they provided wood for building shelter, implements, and fuel for cooking and keeping warm.
They were also the supermarket, chemist, and factory all in one place. Of course, woodlands are also home to many myths and folklore based on the woodlands and the wildlife that lives within them.
Many specialist species of insects, birds and mammals have evolved using these woodlands as their homes and are not found anywhere else.
The biodiversity in ancient woodlands is complex and diverse, with many key plant species slowly developing and expanding. Plants are usually the indicator species for Ancient woodlands since they are static, unlike birds and mammals.
We use vascular plants, those with well-developed vascular tissue that carry water and minerals throughout the plant. These are flowering plants, native conifers, and ferns. We often use them as indicators of ancient woodland.
Sometimes, we will also use bryophytes (mosses), lichens (that grow on trees), and seedlings to measure the health of ancient woodland indicator species. In addition to these characteristics, we need a good substrate (soil on the ground), good primary productivity (plant growth rates), and/or good secondary productivity (species diversity).
Let’s look at some of an Ancient woodland’s key plant indicator species. These species and other features are good indicators that the woodland we are looking at would be classified as ancient.
Wood Anemone (Anemonoides nemorosa) is an early-spring flowering plant in the buttercup family. Other common names include windflower, thimbleweed, and smell fox due to the musky smell of the leaves. It is a perennial herbaceous plant growing 5–15 cm (2–6 in).
In the UK, the wood anemone starts blooming in March through May, soon after the foliage emerges from the ground. The flowers are solitary, held above the foliage on short stems, with three palmate leaf-like bracts beneath. The flowers are usually white but may have a pinkish tinge.
Wood Sorrel (Oxalis acetosella)
Wood Sorrel is an early flowering plant in the daisy family. It is often found in areas similar to those of the wood anemone. It has white flowers with pink or purple veining and three heart-shaped leaves that resemble clover.
Many plants are known as sorrel, the name of which comes from the French word for sour. Wood Sorrel has many local names, such as Fairy Bells and Wood Sour.
The flower and stem are edible, and the taste is sharp and sour, reminiscent of lemon peel. Wood sorrel, which has a high vitamin C content, was used as a treatment for scurvy. Some people will tell you not to eat a lot of wood sorrel, as it contains oxalic acid, a mild diarrhetic also found in chocolate, coffee, and many pulses. Wood Sorrel contains similar amounts and has an invisible effect.
Ransoms or Wild Garlic (Allium ursinum)
The name Ramsons comes from the Saxon word Hramsaass. It’s probably more widely known now as Wild Garlic. It is a perennial plant that grows from a bulb and is a relative of the onion (Allium).
In spring, the single-base elliptical leaves grow before the white flowers appear between April and June in the UK. Wild foragers will use the plant bulb in autumn to flavour their winter salads and stews. Ransoms were used in recipes and were known as ‘healing plants’ by the Celts and Romans. They have several local names, including wild cowleek, cowlick, buckrams, broad-leaved garlic, wood garlic, bear leek or bear’s garlic.
Wild Service Tree (Sorbus torminalis)
I had to include this as I spotted my first one in Sussex this year. When mature, they can grow to around 25 metres tall with a trunk diameter of over 1 metre. The bark is smooth and white-grey. It’s distinctive because it is ‘flaky’ and peels away in squarish sections, revealing the dark brown wood beneath.
Wild service trees flower in early spring with five white petals and cream stems. They are hermaphrodite and insect-pollinated. In autumn, the fruit forms in bunches that resemble small apples and turns from green to a russet brown. The wild service tree is one of the common names, but it is also known as the chequer or checker tree.
Hard Fern
The Hard fern can be identified by its leaves or fronds, which grow directly opposite each other on the stem, giving a herringbone appearance. These fronds are known as single pinnate, which means that each frond is complete and not divided. The fronds taper in at the stem and tip.
Hardy fern is not a food plant for wildlife; no specific insects feed on it, although Red deer have been known to feed on them in an exceptionally hard winter. The rust fungus Milesina blech is specific to hard ferns and occurs on over-wintered fronds.
The hard fern has some medicinal uses. The Celts used the fronds to treat skin problems and sores, and it was also noticed that deer rubbed their antler stubs on the hard fern after they had shed their antlers. The leaves were traditionally used to treat stomach problems and lung disorders, while the rhizome was made into a concentrated liquor used to treat diarrhoea.
Saproxylics
Saproxylic invertebrates depend on dead or decaying wood for part or all of their lives. Beetle larvae often feed on decaying wood.
The best-known example in the UK would probably be the Stag beetle Lucanus cervus. The larvae are saproxylic, living and feeding off decaying wood for three to five years before emerging as an adult stag beetle.
The stag beetle is Britain’s largest insect and probably the best-known of all the beetles. The male is easily recognised by its enormous jaws, which resemble the stag’s antlers. Although they look ‘dangerous’, they can’t bite with their antlers. They can’t eat with them either – the sole purpose of the antlers is to fight other male stag beetles. These fearsome-looking gladiators can only sip nectar during their short adult lives, living between May and August in a single year. It’s not the same with the female. Although physically smaller, she can give a ‘sharp nip.’
Violet click beetle (Limoniscus violaceus)
The adult beetle is black with a metallic blue sheen and around 12mm long. Their glossy, orange larvae, known as wireworms, resemble the mealworms fed to garden birds.
The violet click beetle breeds in decaying wood but has very specific needs. It only breeds in the hollows of Ash and Beech, where the heartwood has decayed into a black mulch, like damp soot. This only occurs in large ancient trees that are hundreds of years old, which are very rare themselves. Because of this, the Violet click beetle is critically endangered. It has only been recorded in three sites in England, and I have yet to see one.
Molluscs
Lemon slug (Malacolimax tenellus)
The Lemon Slug is a rare mollusc species. Its vibrant yellow colour contrasts with its very dark tentacles. An adult is around 4cm in length and only feeds on mushrooms. This means that October and November can be particularly good times to spot it, but these distinctive slugs are rare.
Ash Black Slug (L. cinereoniger)
The Ash Black is Britain’s largest slug and can be up to 30cm when fully grown. The colour is variable from pale grey to jet black. Apart from the sheer size, the main feature is the white-to-tan stripe that runs from the edge of the mantle to the tip of the tail. The pneumostome (breathing pore) is located in the posterior.
Ancient Woodlands – Other Key Identifiers
The lush, green canopy of the ancient woodland was a constant reminder of the long-standing connection between humanity and nature.
The light filtering through the trees illuminated former industry and management markers. Coppiced trees had been cut back to ground level as part of a production cycle, with Hazel and Willow being the most commonly used species.
Pollarding was also employed, cutting back the upper branches to create a dense crown that could be used to build fences and cottages.
Charcoal kilns, mine pits, ore-roasting hearths and furnaces were scattered throughout the woodlands, highlighting how vital these resources were to our ancestors. Alongside them were the remnants of deer parks and other animal grazing boundaries, some of which are still used as parish markers today.
As visitors journeyed through the woodlands, it became clear why they had been such an important part of human evolution and a cornerstone of our culture.
This is the first in a series in which Wildlife Matters will explore the varying types of woodland habitats found in the UK.
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Further Reading
Ancient Woodlands – Woodland Trust