26 Feb 2021

Exploring winter woodlands

Written by Rob Dewar, Natural Heritage Advisor

Bare-branched oak trees grown on a small hillside, with a loch at the bottom. The branches are clearly reflected in the still water against the blue sky.

A winter oak wood

Winter woodlands have a special quality all of their own – this is the perfect time of year to appreciate the composition of a wood and to spot some wildlife.

If the wood in spring is a rich oil painting full of colour and vibrancy, then the winter wood is a pencil sketch of stark contrast – each line highlighting features that are not always seen later in the year. Without the heavy summer foliage, you can actually ‘see the wood for the trees’! With practice, you can learn to identify a tree from distance, as they take on a distinctive character. Try comparing a mature birch tree with an aspen – these trees look rather similar in full leaf but have different branching patterns, which are more clearly seen in winter.

The bare branches of trees in winter, silhouetted against a blue and white cloud sky.

Birch (in the foreground) and aspen trees in winter

Casting your eyes upwards, the open canopy may reveal bird nests or possibly even squirrel dreys, essential for shelter in the harshest of winter days. The Trust has been part of a recent conservation programme to reintroduce red squirrels to woodlands in the north-west of Scotland.

Red squirrel

When the weak winter sun shines, it lifts our spirits but also energises those birds that struggle through the colder months. This is a good time to identify the calls of birds such as tits, when they’re more easily seen without the mask of foliage on the trees. In the plant world, the ‘harbinger of spring’ is the snowdrop, but which bird would you give this label to? How about the bird that shatters the woodland silence by a rapid hammering of its beak on wood? The great spotted woodpecker is more easily seen in winter and early spring, and is always a thrill to encounter. The drumming sound is made on hollow wood, to stake claim to its territory and attract a mate, but you can also be alerted to the woodpecker’s presence by its high-pitched ‘tchack’. These striking birds can be thugs, however, when it comes to ‘drill-raiding’ nest boxes to feed off the eggs or chicks of other birds.

Look for treecreepers as well, as they wind their way up the trunk of a tree. Nuthatches are also beginning to establish further north, into lowland Scotland. All of these species, along with the ever-active dipper, can be seen in the magnificent woodland ravine of Dollar Glen, in Clackmannanshire.

A dipper stands on a rock, facing the camera. It has a brown body, head and wings, with a bright white chest and neck patch.

A small brown and white bird clings on to some rough bark on a tree trunk, facing up the tree. It has a long curved beak and very long toes to grip with.

We manage our woodlands to maintain dead standing timber where it’s safe to do so. Rotten wood – both fallen and standing – is an integral part of the woodland ecology and food chain. Dead standing trees provide good natural nest sites for birds such as woodpeckers and the ten species of bats found in Scotland. An amazing eight of these can be found at Threave Garden & Estate in Dumfries and Galloway, including Scotland’s largest bat (the noctule) that is reliant on tree cavities. The older the trees, the better for creating animal niches.

A view of an ancient oak woodland on a sunny day, with light dappling through the branches. The trunks are thick and gnarled, and some have large moss-covered clumps at the base. Some fallen branches lie on the grassy woodland floor.

There is no better tree for wildlife richness than the oak, and the Old Wood of Drum in Aberdeenshire (seen above) is one of the woodland jewels in the Trust’s care. This ancient pasture wood has oaks that are many centuries old, and their gnarled, distinctly individual shapes are best seen highlighted by the winter sun.

Another protected woodland in our care is the Coille Mhòr on the scenic Balmacara Estate. This woodland is part of ‘Scotland’s rainforest’, also known as Atlantic woodland or coastal temperate woodland, and is incredibly rare on a global scale. One of the biggest threats to these woodlands is the invasive Rhododendron ponticum, and Balmacara is one property making great strides in controlling the choking impact of this plant. The Trust is a leading exponent of ‘stem treatment’, a targeted control method to protect the sensitive plants that thrive in Scotland’s rainforest.

Read more about Scotland’s rainforest

Bare and withered rhododendron plants stand under an oak tree canopy in Balmacara in autumn. A shimmering loch lies just behind.

A patch of bare, dead-looking branches and twigs from a rhododendron plant can be seen in a woodland clearing. It is surrounded by green mossy rocks and lush vibrant trees.

Winter also offers the best time to appreciate the richness of epiphytes – species that thrive on host trees and extract all their required moisture and nutrients from the air. Mosses (bryophytes) and lichens thrive in Scotland’s rainforest, where some of the rarest species in the world can be found. Some trees are dripping with long-haired (or beard) lichens such as the Usnea species, whilst others are encrusted or appear much more leaf-like. One such leaf-like species that has become rare in parts of Europe, due to air pollution or acid rain, is Lobaria pulmonaria. It’s commonly known as ‘tree lungwort’ because it resembles the lobes of a lung, and it thrives in clean air. Other ‘foliose’ lichen to be found in the woodlands of Balmacara are the yellow/golden specklebelly and the nationally rare Norwegian specklebelly. Such charismatic names for fascinating lichens.

Lichen grows on top of some moss, in a woodland setting. The lichen is brown with white spots, and has long, thin leaf shapes.

Lichens are not widely appreciated, but they are incredibly useful. You may be aware of their use in producing dyes and cosmetics, but did you know lichens are very accurate at dating surfaces and have been used in archaeology to date ancient monuments? They’re also particularly useful to scientists when monitoring atmospheric pollution levels and the presence of metal toxins.

Quote

“I like to observe and photograph lichens, whilst enjoying the patchwork of colour on tree trunks or exposed rocks – ‘nature’s palette’. Have a closer look yourself and take a deep breath, appreciating the comparatively clean atmosphere.”

Rob Dewar

A half portrait photograph of a man, standing in leafy woodland. He has short grey hair and wears a black outdoors jacket. He is smiling at the camera.

Woodland bryophytes are best seen in winter too, when they’re at their most lush and vibrant in colour. Look on the woodland floor, rocks, logs and tree branches for species such as wood hair moss (Polytrichum formosum), fork moss (Dicranum scoparium), step moss (Hylocomium splendens), tamarisk moss (Thuidium tamariscinum) and stiff moss (Rhytidiadelphus loreus). These are just a few, but they’re some of the more common species that you’re perhaps most likely to spot.

A close-up of a bright, lime green clump of moss. It has lots of 'blades' that are split in two, creating a rather feathery effect.

A close-up of a bright green clump of moss, with star-like bursts of stems.

In some forests on humid winter nights, peculiar ice crystals form on rotting wood. Hair ice looks like bursts of hairy cloud or sometimes a bit like candy floss. It is neither. These hair-like wisps appear at night and melt when the sun comes up. Scientists have now discovered exactly what gives hair ice its strange shape: it’s caused by a fungus called Exidiopsis effusa. Hair ice only grows when the temperature is just below 0°C.

Hair ice

The Trust cares for some wonderful woodland places across Scotland. Wherever you choose to visit, remember to enjoy the winter woodlands for what they reveal, rather than what lies dormant.