The death of a tree marks a long, drawn-out process, and one which is incredibly important for nature. In its death throes over months and years the dying plant supports a bonanza of wildlife. Deadwood, both standing and fallen, provides habitat and nourishment for a dizzying array of species. Bats and birds nest in the hollows, creepy crawlies lay their larvae under the peeling bark and mysterious fungi envelop, shroud and ultimately dissolve the tree’s decaying corpse.
The Grim Reaper takes his time with trees
So you see, for a tree, death is a strange thing. It’s not death in the final sense that we tend to think of, but a gradual process. It includes loss of individual limbs and the appearance of scars, tears and rot holes. This leads to the eventual decay and hollowing that’s characteristic of our cherished ancient tree giants.
The ancient phase may be the longest phase in a tree’s life. For example, an oak tree living out its natural lifespan will begin to die early on, perhaps in less than 300 of its 1000 or so years on the Earth.
Decaying wood is good!
In fact, for healthy functioning woodland, death and decay are positively desirable. If anything, UK woods don’t have enough deadwood! It tends to get cleared away during thinning, for use as firewood or chipped for biomass. Standing deadwood is a particular rarity and this means the wildlife that depends on decaying wood for sustenance – so-called saproxylic species – is similarly scarce. One of the best-known saproxylic species in Britain is the stag beetle, whose larvae feast on these dead and decaying wood corpses.
A woodland ecosystem is a wondrous cycle of birth, life and death. At this time of year when the leaves fall to the floor, the soils – and the worms, insects, fungi and bacteria they contain – are stirred into activity. They devour and decompose the year’s bounty, recycling much of it into nutrients that will feed the trees in the following spring.
These species rely entirely on the trees’ ability to harness sunlight, using it to split carbon dioxide and generate new growth. Trees are fundamental to the ecosystem. Their life - and their death - is special, important. It’s one of the many reasons we value them so much.
Ghosts in the landscape
Look around on a spooky autumnal evening. The crooked, contorted spectres of the dead and dying surround us all – the ancient trees in our countryside are testament to past forms of land management.
Look at an aerial photograph and compare it with an old map. You can often spot the dark lines of richer soils that mark where the trees and hedges once stood. Chances are you'll find hedgerows on the old map that simply don't exist anymore. Or, where they do, there are ghosts of noble trees long since gone.
The is a Ancient Tree Inventory great place to contrast and compare map layers. You can experiment and see first-hand what we’ve lost over time.
They were there for a reason. They produced fuel, construction materials and fodder. Most were managed as pollards, having their main trunks cut at a height beyond the reach of livestock. This prompted the tree to respond by growing multiple branches from the cut head, which were then repeatedly harvested on a 10-15 year cycle.
Stepping stones for ghoulish species
Pollards themselves can become extremely ancient - oaks can live for a thousand years, maybe more. Pollarding doesn’t necessarily increase the lifespan of the tree, although it does stop it being blown over.
As these trees grow older, their gnarly, twisted branches and eerie silhouettes provide vital habitat for the decay-loving saproxylic species.
Distributed throughout the patchwork of hedgerows, these pollards are useful stepping stones to help those deadwood-loving species move through the landscape.
Some of these old trees remain today, although they are seldom still managed as pollards. Lapsed pollards are prone to splitting apart as the weight of the overgrown branches becomes too great for the crown to bear. Even then they aren’t always finished - sometimes the shards continue to live, other times the tree begins to enter another phase, known as layering. These ‘phoenix’ trees show just how tenaciously trees hang onto life.
Dare to seek out ancient trees this All Hallows Eve?
Spare a thought for trees on Hallowe’en, and for the thousands of miles of hedgerows that have disappeared from our landscape over the last century. Dying is an ordinary part of life for a tree, but one that supports the amazing diversity of wildlife that we all enjoy.
Visit your local wood to look out for deadwood and enjoy the sights, smells and sounds of autumn. If you manage to spot an ancient tree, add it to the ancient tree inventory. Your records help us to protect these special trees for people and wildlife. Don’t let them become ghosts too.