Our wood is not neat. When trees have dropped branches on to the ground, unless they cross the paths, we don’t move them. If trees die, we don’t cut them down unless we, or our camp, are in imminent risk of being flattened by the falling trunk. There are areas of the wood you have to skirt round when you’re not in the mood for a serious obstacle course, and we do exercise caution, postponing visits if the wind is too aggressive. In places, the wood does look like a tangled mess. But clearing the dead wood is not on our agenda, not because tidying the wood is low on our priority list, but because deadwood is a priority.
Keeping dead trees and fallen branches may not initially seem a logical thing to do – it may appear on the surface that the custodian of this woodland is being a bit lazy, not putting in the hours. But it is estimated that up to 40% of woodland species are dependent on dead wood in some way; without the dead wood, the biodiversity in the woodland crashes.
Compared to the forests of thousands of years ago, most woodlands are very neat. Dead wood has been taken for fuel and building, it’s been cleared to manage pests and fungi in woodland where timber is a business, and actually just to make the wood look tidy. But it has been estimated that a healthy woodland should have up to 30% deadwood. It is said there is more life in a dead tree than in one which is alive…
Dead wood includes fallen branches on the ground, dead branches in the tree, stumps, fallen trees, and dead trees still standing (called snags) – the bigger the diameter of any of these things the better. Trees grow by laying down new tissue under the bark – hence the rings we see in a tree’s trunk, the rings we count to work out the age of a tree. The inner wood dies as the tree expands and this forms the heartwood. The bark protects the tree, but as soon as there is a way in (a fallen branch, a woodpecker hole) fungi will begin to work their way in to the heartwood. The fungi start the decay, small holes form, and saproxylic invertebrates (those that are reliant on decaying wood / dead wood for part or all of their life cycle) such as beetles, hoverflies, wood lice and wasps, move in. They come to live in it, feed on it, lay young in it or parasitize those species present in it.
The dead wood is bursting with nutrients; it provides specialist habitats for invertebrates and fungi, mosses and ferns, and these in turn support the birds, invertebrates, bats and other small mammals which eat the saproxylic invertebrates and fungi. Birds, bats and small mammals live in the decay holes (one third of woodland birds nest in holes or cavities within the trees), and where heartwood is softened by decay, animals can excavate holes where a suitable hole is not present. As the cycle continues, these small creatures feed larger mammals and birds of prey. (So much of our deadwood shows signs of being ‘badgered’, and it’s always a pleasure to watch a badger getting really stuck in to a rotten stump or trunk in its search for food.)
Dead wood’s virtues don’t stop here. It is a form of carbon storage, and as it gradually breaks down, it forms a slow and steady nutrient source for the woodland. It helps to stabilise the soil of the woodland floor and where it still stands, makes excellent roosts for owls and woodpeckers, and clear, visible perches from which birds can sing.
It is sad when trees fall or drop sturdy, fern encrusted branches. But as the tree comes to the end of its life, it has yet to reach its peak of usefulness. It will provide nutrients, cover, food, a home, a place for creatures to sun themselves, rest, stand lookout, drum, nest, hibernate. Dead wood is a key part of any woodland, and throughout the country we are losing it, fast. So when I see a messy woodland, with the ground strewn with branches and trees propped against others, with stumps gradually rotting and trunks criss-crossing the floor like some giant game of pick-a-stick, I don’t frown on the lazy woodlander who owns it. Instead, I celebrate their insight and remember – heartwood doesn’t stop supporting life when the tree it supported is no longer living.