Tree of the month: October 2024 - Aspen

The Aspen, or Quaking Aspen is native to the UK. It was an early coloniser along with Birch and Willow, arriving around 12,000 years ago as the Ice Age ended. Aspen grows quickly, and is tolerant of many soils. Able to grow to around 25 metres, individual trees can live for at least 100 years. However, Aspen spreads by underground root-systems so, while individual trees may not live long, new trees sprout from the root systems and can spread for over 40 metres, forming a ‘colony’ which is recognised as one single organism. The most numerous tree in North America, producing stunning stands of yellow trees in autumn, there is one Aspen colony that is older than any Sequoia: a colony in Utah Fishlake National Forest has been estimated at 80,000 years old weighing an estimated 6,600 tons. If Aspen trees are felled or burned down the roots can lay dormant and regrow.

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​The round, wavy-edged leaves, paler on the underside, are a good way to identify Aspen. Also look for the flattened leafstalks. It is this feature that allows the shimmering of the leaves and the whispering sound associated with Aspen, which give rise to its scientific name ‘Populus tremulus’.

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Wildlife value of the Aspen: The Aspen tree enhances biodiversity. It can be an indicator of ancient woodland in areas like the Caledonian Forest, though our small stand of trees on Parkwood Springs are relative newcomers.

A wide range of moth larvae feed on the Aspen, including the Figure of Eighty and the Poplar Hawkmoth.

There are over 50 species of invertebrates associated with Aspen, including beetles, flies, sawflies, the Poplar Leaf-rolling Weevil and, specific to the Aspen, the Aspen Hoverfly, the Scarce Aspen Knot-horn and the Scarce Aspen Midget. Many of these feed on the leaves but some, including the larvae of the Hornet Moth, feed beneath the bark.

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​The pale grey bark of the Aspen is pitted with diamond-shaped pores or ‘lenticels’. The inner layer of the bark, being full of sugars, attracts many animals to feed on it. Overgrazing by deer can cause problems by damaging individual trees and more especially by grazing off the new shoots generating from Aspen’s underground root-system. Aspen is also a favourite tree of the beaver. Voles and mice seek out the bark of the tree for its nutrient-rich food. As it ages, the bark supports many types of lichen and moss.

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​Fungi, including Scalycaps, will grow on Aspen. Mutually beneficial mycorrhizal fungi in the soil exchange nutrients with many trees but this especially benefits Aspen, helping to nourish and protect the widespread root-systems from which new clones of the original tree will grow into mature trees.

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​Aspen Flowers: Though spreading by their root systems, Aspen is also spread by seed. They are dioecious (male and female flowers are produced on different trees). The reddish male catkins appear between February and April. Pollen is carried from these by wind to the female catkins which, when pollinated, produce fluffy seeds in summer, which are, again, dispersed by the wind.

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​Human uses of Aspen: The soft, light-weight, close- grained timber neither burns or splinters easily. These qualities, plus its lack of taste or scent and its buoyancy explain its many uses. Aspen has been made into matches, paper, chopsticks, paddles, milk-pails, surgical splints, herring barrels and packing cases. The inner bark has been dried and ground for flour for bread and to thicken broth. The sugar rich sap, tapped in spring, has been used in drinks.

Herbal Uses: Because Aspen bark, like that of Willow, contains the aspirin-like salicin, it has long been used medicinally to treat ailments like rheumatism, neuralgia and to reduce swelling and inflammation. Many Native Americans and others still value its analgesic and antiseptic qualities.

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​Myths and Symbolism of Aspen: For Celts the Aspen was linked with transformation and regeneration. An Aspen stick was known as a ‘stick of woe’, signifying the Underworld was nearby. In Ireland the mythical hero Cuchulain was said to carry a shield of Aspen to protect him from fear while Irish heroes were buried with Aspen wands to give life after death for their souls. Linked to their whispering sounds an Aspen leaf under the tongue was thought to bestow eloquence, gifted by a faery queen. In Christianity, Aspen was believed to have formed the cross carried by Jesus to his crucifixion.

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​Interesting fact about Aspen: When defoliated they are believed to emit natural herbicides to deter further predation of their leaves. Research is revealing that how protections and signals of threat are produced and transmitted by plants.
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The Aspen tree in poetry: Gerard Manley Hopkins, one of the most important poets of the Victorian era, wrote this powerful lament on ecological destruction when a stand of Aspen were cut down at Binsey, on the banks of the Thames, near Oxford.

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​Gerard Manley Hopkins, 1844-1889
Binsey Poplars (felled 1879)
My aspens dear, whose airy cages quelled,
Quelled or quenched in leaves the leaping sun,
All felled, felled, are all felled;
Of a fresh and following folded rank
Not spared, not one
That dandled a sandalled
Shadow that swam or sank
On meadow & river & wind-wandering weed-winding bank.
O if we but knew what we do
When we delve or hew-
Hack and rack the growing green!
Since country is so tender
To touch, her being so slender,
That, like this sleek and seeing ball
But a prick will make no eye at all,
Where we, even where we mean
To mend her, we end her,
When we hew or delve:
After-comers cannot guess the beauty been.
Ten or twelve, only ten or twelve
Strokes of havoc unselve
The sweet especial scene,
Rural scene, a rural scene,
Sweet especial rural scene.

Edward Thomas,1878-1917: Aspens
All day and night, save winter, every weather,
Above the inn, the smithy and the shop,
The aspens at the cross-roads talk together
Of rain, until their last leaves fall from the top….
The whisper of the aspens is not drowned,
And over lightless pane and footless road,
Empty as sky, with every other sound
Not ceasing, calls their ghosts from their abode….
Whatever wind blows, while they and I have leaves
We cannot other than an Aspen be
That ceaselessly, unreasonably grieves,
Or so men think who like a different tree.