Why Dead Wood Matters for Garden Wildlife

British gardeners are, on the whole, a tidy lot. We cut back, rake up, bag up and cart off to the tip, feeling virtuous as we go. But every wheelbarrow-load of dead stems and rotting timber we remove is a small eviction. A garden stripped clean of dead wood is a garden missing an entire layer of its wildlife — and it is often the layer that does the most work.

Leaving a pile of logs in a quiet corner is one of the cheapest and most generous things you can do for wildlife. It costs nothing, needs no maintenance, and gets richer with every passing year. Here is how to do it well.

What Actually Lives in a Rotting Log

A fallen branch is not a dead object; it is a slow-moving feast. Fungi break it down first, threading invisible hyphae through the timber and softening it. Then the invertebrates move in: woodlice, millipedes and fungus gnats, beetle larvae chewing tunnels under the bark, and the spectacular grubs of the stag beetle, which can spend five or six years inside the same piece of decaying wood before emerging.

Look closer and the list grows. Centipedes hunt in the damp gaps. Solitary wasps and hoverflies lay eggs in abandoned tunnels. Bats roost in hollows. Even the fungi themselves are worth having — bracket fungi, candle-snuff fungus, and the strange slime moulds that appear overnight on wet wood.

• Beetles: stag, lesser stag, click and longhorn beetles all need decaying wood at some stage of life.
• Fungi: the true recyclers, turning timber into soil and feeding everything above them.
• Woodlice and millipedes: the clean-up crew, grazing on softened wood and fungal threads.
• Predators: centipedes, spiders and ground beetles follow the prey in.

A Winter Shelter You Cannot Buy

Dead wood comes into its own from October onwards. A log pile holds warmth and moisture far better than a bare border, and its nooks and crannies are exactly the sort of place insects look for when the temperature drops.

Brimstone, comma and peacock butterflies tuck themselves into crevices. Ladybirds cluster in bark cracks in groups of twenty or more. Queen bumblebees, freshly mated, burrow into loose soil and leaf litter beneath the logs. Lacewings, solitary bees and overwintering hoverflies all use hollow stems, and a bundle of dry stems left standing is prime estate for a solitary bee looking for somewhere to wait out the cold.

It isn't only insects. Frogs, toads, newts and slow worms use damp log piles as hibernation sites, and a hedgehog may well choose a sheltered corner between the logs and a hedge. Once you have the invertebrates, the birds follow: wrens, robins and dunnocks will pick through a log pile all winter, and a great spotted woodpecker will happily work over a standing dead trunk.

Choosing a Spot

The trick is to put your dead wood somewhere you will not be tempted to interfere with it. A quiet corner behind a shed, along a north-facing fence, under a hedge or at the back of a shrub border are all ideal. Dappled shade and reliable damp suit fungi and the creatures that feed on them.

Aim for roughly a square metre to begin with — bigger is better, but a single log is a genuine improvement on nothing. Try to include both a sunny, south-facing log that will warm up and offer a basking spot, and a shaded, damp one for the rot-lovers. Keep the pile clear of wooden sheds, fences and house walls, where constant damp could cause problems for the structure itself.

How to Build It

• Keep the bark on. That is where much of the life is, and it holds moisture.
• Mix sizes. Thick logs rot slowly and last for years; thinner branches break down quickly and feed the soil.
• Part-bury the base. Contact with soil speeds up colonisation by fungi and invertebrates.
• Stand some pieces upright. Vertical stumps and logs stay damper and attract different species to a flat pile.
• Add a stumpery. An upturned tree root or a buried stump, planted with ferns, makes a handsome feature and a superb habitat.
• Leave standing stems. Cut hollow-stemmed perennials such as teasel, fennel, rudbeckia and sedum at 30–60cm and leave the stubs over winter. Tie a few into a bundle for good measure.

Never use treated, painted or tanalised timber, and never move wood long distances from elsewhere — that is how pests and tree diseases spread. Anything from your own garden or a local source is fine.

What to Expect

Nothing much happens at first, and then everything does. Fungi appear within a season or two. Woodlice and beetles follow. By the third or fourth year a good log pile is a small, self-running ecosystem, and you will find yourself crouching beside it with a torch on mild winter evenings, counting things.

Leave it alone. Do not turn it, tidy it or move it. If you must add something, add more wood on top and let the bottom continue its slow work. The best garden habitats are the ones we stop managing, and a corner of dead wood is the easiest gift you can give to the wildlife that shares your patch.