Why rotting wood deserves a place in the garden

A pile of old logs can look untidy to a human eye and like a five-star hotel to almost everything else. Dead and decaying wood is one of the richest habitats in the British countryside, and it is exactly the thing our tidy gardens tend to lack. In a woodland, a fallen branch is slowly taken apart by fungi, beetles, woodlice and centipedes, and that process feeds a whole chain of life above it.

Build even a modest log pile in a shady corner and you are recreating a slice of that. Stag beetle larvae, lesser stag beetles, violet ground beetles, bark beetles and all manner of fungus gnats will find it. Solitary bees and hoverflies will use the gaps. Frogs, toads and slow worms will shelter in the damp crevices, and a hedgehog may well tuck itself in for the winter among the leaves at the base. None of it needs to cost anything, and very little of it needs doing twice.

Choosing the right spot

Position matters more than size. The aim is somewhere that stays cool and damp for most of the year, because rot is a slow, moist business. A north- or east-facing edge of the garden is ideal, particularly at the foot of a hedge, under a deciduous shrub, behind a shed or in that awkward shaded strip where little else thrives.

Keep the pile at least 30cm away from house walls and timber fences, purely to avoid trapping damp against structures you would rather keep dry. Avoid anywhere that floods and sits under water for weeks, and avoid full sun, which will dry the wood out and slow everything down. If you only have a sunny garden, a spot shaded by a shrub for part of the day will still work well. And do not put the pile on top of a favourite clump of primroses; you will be leaving it in place for years.

What to stack, and what to avoid

The single rule that matters is untreated wood. Anything that has been creosoted, varnished, painted or pressure-treated with preservative has no place in a wildlife pile, and nor does old decking or pallet wood that may have been chemically treated. Logs from a tree surgeon, prunings from your own trees, or a few lengths from a local wood are all perfect.

• Hardwood is best: oak, beech, ash, birch, apple, cherry, willow and field maple all rot slowly and support a wide range of species.
• Softwood is fine too: pine and other conifers break down faster, which means quicker colonisation but a shorter life.
• Mix your sizes: logs roughly 10–30cm across and 30–60cm long are easiest to stack, with smaller branches and twigs stuffed into the gaps.
• Avoid moving ash: because of ash dieback, it is best to use ash wood from your own garden or site rather than transporting it from elsewhere.
• Add a little soil: a few spadefuls of garden soil or leaf mould brushed into the gaps helps fungi and invertebrates get a foothold.

How to build it

There is no wrong way, but a few small choices make a big difference. Start by laying the largest logs directly on bare soil, not on paving or membrane, and push them down slightly so they make good contact with the ground. Damp soil wicks moisture up into the wood and keeps the whole pile alive.

Stack the next layers at right angles to the ones below, alternating direction as you go up, and leave visible gaps rather than wedging everything tight. Add a scatter of twigs, bark, woodchips and dead leaves between the layers. Aim for something around a metre across and half a metre high if you have the room, but two or three smaller piles in different corners will suit more creatures than one big one, and they are easier to fit into a small garden.

If you want solitary bees as well, drill a few 8mm holes into a log end and stand it upright in a sunnier spot, facing south. Keep that one dry; it is a different habitat from the damp pile.

Finishing touches that make a difference

A log pile improves the moment you stop tidying around it. Let fallen leaves gather at the base and leave them there through winter. Allow moss, ivy and ferns to move in, and plant shade-lovers such as wood anemone, foxglove or native ferns nearby to soften the edges.

A shallow dish of water set into the ground a metre or two away will be used by frogs, toads and hedgehogs, and a small patch of long grass next to the pile gives amphibians a safe route in and out. If you have space, join the pile to a hedge or a compost heap with a strip of rough grass, so wildlife can move between them without crossing open ground.

Patience, and leaving it well alone

The first year, a new pile mostly sits there. By the second summer you should see fungi, holes appearing in the softer wood, and beetles and woodlice underneath when you lift a log. By year three the bottom logs will be crumbling and hollow, which is exactly what beetle larvae and hibernating amphibians want.

After that, the main job is restraint. Do not move or turn the pile between October and March, when something may be hibernating inside. Do not burn it, and do not tidy it away because it looks scruffy. If you need to top it up, simply lay fresh logs on the top and let the older ones continue rotting below. Always lift logs carefully rather than rolling them, and check before you move anything in winter. Rot is the point, and every crumb of it is doing a job.