Why is ancient woodland special?
Ancient woodland is home to more threatened wildlife than any other land-based habitat in the UK. And ancient woods are rare in their own right - some may even be the last fragments of the wildwood that once cloaked the country after the last Ice Age. Just two per cent of the UK’s land area is now covered by ancient woodland, making it crucially important that what remains is properly protected.
Hidden treasures of the soil
The real value of ancient woodland is what’s hidden beneath the leaf litter. Ancient woodland soils are unique, rich in nutrients and still have the original layers laid down by centuries of falling leaves. They’ve developed without disturbance from ploughing or chemicals and are alive with fungi, insects, microbes and worms.
Over time, the creatures and microscopic life forms living in these soils have developed close-knit communities and relationships that we are only just beginning to discover and understand. Woodland floor plants have also evolved alongside these communities, often coming to depend upon them for survival. Some orchids, for instance, rely on certain kinds of fungi for nutrients, and in some cases their seeds won’t germinate without their presence.
A precious home for wildlife
These communities and relationships have developed over hundreds or even thousands of years. This means that certain species are only ever found in ancient woods. They are often slow to spread and do not colonise new woodland easily, so even younger woods that are located next to ancient woodlands will generally not have the same level of diversity.
This also means that the presence of some plants and animals in a woodland can be used to help determine its age. These are known as 'ancient woodland indicators'. The more of these species found in a wood, the more likely it is to be ancient. Wood anemone, bluebell and sweet woodruff are key species to look out for across the UK, as well as wood spurge and yellow archangel in the lowlands, and cow-wheat and sanicle in the uplands.
Lichens, liverworts and mosses can also help to identify ancient woodland. Some require old trees on which to grow and are more likely to be found in woods that have not been coppiced.
Old trees and deadwood
Veteran trees, standing deadwood, and fallen logs and branches are easily overlooked, but are one of the most important habitats for wildlife. They provide homes for species that live, feed or nest in holes in dead and dying timber, and for aquatic creatures that live in the pools created by fallen logs and branches. There are many species of invertebrates, fungi and bacteria which only eat deadwood. These in turn provide food for small mammals, birds and amphibians.
Deadwood is vital for woodland health. Its breakdown recycles nutrients back into the soil and can help with moisture retention. It also helps to stabilise slopes and prevent soil erosion in during storms and heavy rain.
Clues to the past
Humans have relied on woodland for centuries. Many archaeological features can be found hidden among trees, evidence of hundreds or thousands of years of continuous human activity. They’re also irreplaceable and need protecting. Once lost they’re gone forever, and we lose another small piece of the jigsaw in the story of human culture.