Nick Gates – December 2020
There is a weird craze amongst a certain type of well-meaning nature lover. It involves taking an axe, leatherman or small saw, and severing limbs. Not at random, but of one of our favourite and most important Christmas plants. Ivy.
You’re probably all familiar with the aftermath of this particular wild crime scene – most obvious in winter once the deciduous leaves have fallen. On two recent walks around Bristol, I found abundant evidence that this practice is still very much still in use. Scanning the trunks and canopy of a favourite local woods, I find what should be a deep verdant canopy of ivy has been reduced to ruin, devoid of leaves, the furry dead vertical arteries left swaying in the breeze as their crumbling anchor points – carefully glued to the bark of the tree – give way to decomposition:
Fig 1 and 2. Ivy cut against tree trunks. A new shoot is attempting to restart the same vertical journey.
Inspecting the surrounding trees, I can see that this particular individual has been on something of a rampage. Everywhere I look, ivy limbs, including some fantastic mature specimens that must be decades old, have been hacked in half. The plants have no way to recover from this damage.
Fig 3 and 4. A teenage ivy limb sliced off an oak tree by the side of a public footpath.
The reasons that individuals still do this is normally not just reckless environmental vandalism. It is founded in a belief that ivy, being a climbing vine, damages the species that it happens to be using as its trellis. This is further reinforced by the familiar sight of dead or dying trees coated in a dense jacket of ivy, leading to the assumption that it must have been the ivy responsible for the tree’s demise. Ivy on majestic oak trees is met with disdain. The oak – a species quite capable of living for one thousand years if we simply leave it alone – surely must need ‘protecting’ from this persistent pest? The truth couldn’t be further from this.
Ivy is, in fact, one of the most important species in a healthy woodland. Coating large areas of the ground, it becomes a huge blanket, lessening the effects of a harsh frost or snowfall and allowing everything from blackbirds to bank voles to still forage amongst its leaf litter on even the coldest days. In spring, this same ground coating provides nesting opportunities for birds such as robins and wrens – where in young or coppiced woodlands it can provide almost all of the suitable nesting sites for these species. Throughout spring and summer, song thrushes, wrens, spotted flycatchers and many more depend on ivy’s camouflage to hide their nests – its large leaves helping create hidden compartments even against the most exposed trees. Over time, the gentle swaying of large trees slightly flexes and dislodges older ivy, leaving narrow crevices between its thick limbs of the bark of its host. These are readily exploited as day roosts by pipistrelle bats. Come the autumn, ivy flowers provide one of the final sources of nectar and pollen for invertebrates eager to stock up before their winter slumbers. And throughout the winter, fat-rich ivy berries provide a life-supporting food source for thrushes, wood pigeons and even blackcaps.
Fig 5. A spotted flycatcher nest tucked amongst a mature ivy.
But of all the many creatures that enjoy the many habitats and food sources created by ivy, there is one much-loved species that enjoys the comforts of ivy more than all others. Tawny owls prefer to nest in cavities. Whilst one bird is usually found sitting on the eggs or chicks, its mate has to find another nearby spot to keep guard. And given the choice, it will almost always find a dense stand of ivy to tuck up in, one eye half open, keeping watch on the diurnal world that it prefers to avoid. If you’ve ever walked through an ivy filled woodland and heard a cacophony of magpies, jays and crows – usually accompanied with the echoes of blackbird calls and tit flock alarms – there’s a good chance it’s because those birds have found a day roosting tawny owl. All of these birds have good reason to be scared of their woodland nemesis – a species quite capable of killing them or their young. Often, the owl can only take so much of the mob, before decamping and heading off to find a quieter ivy stand – normally to return under the safe cover of darkness.
So if you hear of someone trying to convince you that ivy is damaging to trees – please politely explain that trees and ivy were happily coexisting for millennia before we came along, and if left alone, will continue for millennia after we’ve gone. Cutting ivy from trees, even in a woodland well coated with ivy, is not conservation – it’s environmental vandalism. I’d much rather see tawny owls and pipistrelles, song thrushes and spotted flycatchers on my walks – than scars of dead ivy. And if every now and again a collective of ivy plants do succeed in bringing down an old tree, normally aided by a winter storm, it’s a natural event – helping provide the deadwood fuel for the woodland’s perpetual biodiversity engines. Until then – the combined relationship between ivy and its host trees will provide food, nesting sites and shelter for hundreds of different species.
Nick Gates, guest editor
Nick Gates is a naturalist, wildlife producer and author based in Bristol. He can be found on social @NTGates. His book ‘Orchard: A Year In England’s Eden’, co-authored with Benedict Macdonald, was released by Harper Collins in August 2020.
Bristol Tree Forum 