Woodlands are iconic habitats – people associate them with new life, a healthy environment and more and more often with their potential to store carbon. But every woodland is different, and there are a wide variety of forest types in the UK. Claire Thorpe explores spring woodlands, including species to look out for and how we care for the woodlands at CAT.
Woodlands flourish in spring. In many of these habitats, leaves unfurl, sticky buds burst to life and the woodland floor becomes dotted with colour as the flora there gets ready for the new season. Forests are some of our most biodiverse habitats, with a huge range of invertebrates, mammals, birds, plants and fungi all reliant on woodlands for food and shelter. However, woodland is not a one size fits all term. There are many different types, all with their own unique characteristics and assemblages of species.
Soil type, geology and climate can all affect the woodland found in an area, and tree age will also help determine the habitat’s character. Just 13% of Britain is covered by woodland, well below the EU average of 38% (jumping to 46% for Europe if we include Russia). Once, our forests would have been vast, but hundreds of years of harvesting and destruction drove our tree cover right down to lows of just over 5% after World War 2. Despite this, we are fortunate to host some extremely rare forests, including temperate or Atlantic rainforest, found in areas including the west of Wales and forest habitat around CAT. Afforestation schemes have helped increase tree cover again in Britain. However, planting has not always been sensitive to the requirements of wildlife or
done in the right place.
Getting out to visit your local woodland can be very rewarding, with lots to look out for. These habitats, including the woods around our eco centre, often need careful management to create or maintain the spaces needed by certain animals or plants. Ensuring a diversity of tree ages, maintaining differing light levels and removing invasive non-native species are all ways to sustainably care for woodland habitats.
Broadleaf woodlands are probably what you picture when someone mentions a British forest. They may contain iconic native species such as oak and beech, and some areas hold fragments of ancient forests, hundreds of years old. The trees found here are seasonal, their leaves turning to fiery autumn shades before they are dropped, then going through a period of stunning regrowth in spring.
In the south of England and Wales, magnificent beech woodlands grow on dry, chalky soils. Thick carpets of leaves build up on the ground, where little light reaches, thanks to a dense canopy. These conditions mean there can appear to be few plants growing in the lower levels, but some specialists thrive, such as the rare violet helleborine and bird’s nest orchids. In spring, you may also find carpets of bluebells on the woodland floor, flourishing before the leaves of the trees create a full canopy. As the trees age, their bark cracks and knots, providing a home for many invertebrates and cavity-dwellers like the great spotted woodpecker. Beech trees have a shallow root plate and are therefore susceptible to storms and droughts, making them particularly vulnerable to climate change.
Majestic oaks often form mixed woodlands with ash or birch, as well as smaller numbers of other deciduous trees. These woodlands have a patchy canopy, so a dense layer of shrubs and wildflowers grows on the forest floor. Mixed oak woods come alive in spring, as oaks support more species than any other tree. Hundreds of invertebrate species can live in oak woodlands, and some rely on this tree for food. For example, the purple hairstreak butterfly caterpillars will only feed on oak flowers and leaves. The diversity of insects means there is a wide range of birds and mammals in these forests. Mixed woodlands provide an abundance of food sources, and no two woods are the same, meaning you never quite know what you’ll find on a visit!
Along parts of the west coast of Britain, oak habitats, mixed with hazel, birch and pine, form extraordinary habitats known as temperate rainforests. Higher humidity and rainfall than other forests mean these wet areas host hundreds of species of moisture-loving lichens and mosses. These plants create microhabitats on the trees, perfect for invertebrates, which in turn bring in creatures higher up the food chain. Near CAT, there are excellent examples of temperate rainforest, including in the Dyfi Forest and Ceunant Llennyrch National Nature Reserve. Visitors to the eco centre might be lucky enough to spot a pretty pied flycatcher, these birds arrive in late spring after a winter in Africa and are specialists for the mild, damp conditions created within a temperate rainforest.
Temperate rainforests would have once covered large swathes of our coastal areas, but many have been destroyed and overgrazed. The remaining fragments are more vulnerable to future threats like the changing climate and invasive species. Rhododendrons, originally from Asia and North America, will aggressively swamp woodland habitats and quickly establish themselves as the dominant species. They are expensive and difficult to remove, and research suggests they may leave behind chemicals in the soil that inhibit the growth of other species, a phenomenon known as allelopathy.
Native coniferous forests are unlikely to be a familiar habitat to most of us, as most pine habitats in the UK are comprised of non-native trees in plantations. These planted areas have low value to wildlife, as the trees do not support many of our native species, and techniques which strip the land of trees can be very damaging.
Yew, juniper and Scots pine are Britain’s only native conifers. Yew forests are rare, and these densely shaded habitats tend not to be especially diverse, although the trees themselves are often ancient. On the other hand, Caledonian pine forests, only found in a few parts of Scotland, are home to rare and unusual species. Large Scots pines are often mixed with smaller deciduous trees like rowan and hazel, creating mixed canopies and varied habitats. Red squirrels feast on the seeds of Scots pine, while birds like the crested tit, found nowhere else in the country, hunt down insects within the fissured bark of the tall ‘granny trees’ that dominate the landscape. Overgrazing and harvesting have reduced Caledonian pine forest to just a fragment of their former glory, where they would have once covered much of Scotland.
A helping hand
Not all woodlands need to be managed, but human intervention can help increase the value of some forested areas for wildlife, as well as provide a sustainable source of income.
At CAT, we carry out coppicing of the woodland around the eco centre. This practice, involving cutting down stands of trees in rotation over a set time scale, maintains a varied age and light structure in the woodland. Coppicing is usually done to hazel or sweet chestnut trees, and the timber can be used in lots of ways, especially in the garden. The hazel dormouse, found at CAT, relies
on coppiced habitat and parts of our woodland are now managed to ensure their continued presence. Wildflowers and insects also thrive in the dappled light introduced by felling small areas.
You can find out more about our practices in our Sustainable Woodland Management course, which runs throughout the year. The course focuses on the skills and techniques used at CAT’s woodland, Coed Gwern. We carry out continuous cover forestry, which gives a continuous supply of timber while providing cover and keeps some areas protected for wildlife. This contrasts with clear-fell logging, where whole forests are felled at one time. We have also been planting trees and keeping a mosaic of shrub cover. In January, participants on this course saw demonstrations of a chainsaw mill, using a felled Douglas fir.
The wood will be used for a footbridge at the eco centre, and the light created by felling the tall, non-native tree will help wildlife flourish as more light reaches the ground. Our sustainable management is paying off, with pine martens recently identified as inhabiting the woodland, and red-listed woodcock breeding here.
Find out about our upcoming courses and training – www.cat.org.uk/whats-on