Walk through any ancient woodland and you will see the obvious glories: bluebells in spring, a canopy of oak and ash, the drumming of a great spotted woodpecker. But the richest habitat is often the one we tidy away. Deadwood — standing, fallen, rotting — supports more species than almost any other woodland feature. In the UK, around 1,700 invertebrates depend on it, along with hundreds of fungi. The good news is that creating deadwood habitats is simple, cheap and deeply rewarding. You just need to leave things be, safely.

Why standing dead trees matter

A standing dead tree, often called a snag, is the woodland equivalent of a high-rise apartment block. As the wood decays from the inside out, it develops cavities, cracks and softened heartwood that suit a huge range of species. Stag beetle larvae feed in buried rotting wood, lesser stag beetles and longhorn beetles tunnel through standing trunks, and solitary bees and wasps nest in old beetle exit holes. Bracket fungi like beefsteak fungus and chicken of the woods fruit from the sides of dying oaks and ash. If you have a dead tree that is not a safety risk — away from paths, buildings and roads — leaving it standing is one of the single best things you can do for biodiversity. Even a 2–3 metre stump retains enormous value. Where a full tree is unsafe, reduce it to a monolith or a high stump rather than felling to ground level. The decaying root plate alone supports specialist beetles and fungi for decades.

Making a log pile that insects will love

A log pile is not just a heap of timber. Placement and structure matter. Choose a spot in dappled shade, ideally with one sunny edge so cold-blooded insects can bask. Partly bury the bottom logs — contact with soil speeds decay and lets fungi and beetles move in. Use logs of different diameters, from 5 cm to 30 cm, and lengths of 1–2 metres. Keep the bark on; it holds moisture and provides hiding places. Mix species: oak and beech are slow to rot and long-lasting, while ash, birch and willow decay faster and offer quick rewards. Do not use treated timber, painted wood or old railway sleepers, as these can leach chemicals. Stack loosely rather than tightly, leaving gaps and crevices. Add a few handfuls of fallen leaves and some twigs on top. If you can, create two or three piles of different sizes and ages — a fresh pile and one that is already soft and crumbly will support different communities. Avoid moving piles once made; disturbance kills the very creatures you are encouraging.

Fungi: the recyclers you barely see

Fungi do the heavy lifting in deadwood. Their thread-like mycelium spreads through the timber, breaking down lignin and cellulose and releasing nutrients back into the soil. Many woodland fungi are fussy: some specialise in oak, others in birch or pine. You cannot easily introduce most of them, but you can make your site welcoming. Leave fallen branches and stumps in place. Do not clear fruiting bodies — the familiar mushrooms and brackets are just the reproductive tips of a much larger organism. If you want to give things a nudge, you can buy plug spawn for species like oyster mushroom or shiitake and drill it into freshly cut hardwood logs, but this is a bonus rather than a necessity. Keep logs off very dry, exposed ground; moisture is the key. A log pile that sits in a shady, humid corner will soon be laced with white mycelium and dotted with small brown and yellow fungi you never noticed before.

Homes for solitary bees and beetles

Solitary bees are not aggressive and are superb pollinators. Red mason bees and leafcutter bees often nest in old beetle holes, so a standing dead tree with its natural cavities is better than any drilled bee hotel. If you want to add extra nesting sites, drill clean holes 6–10 mm wide and about 10 cm deep into the side of a log that faces south or east. Do not drill all the way through, and replace the log every few years to avoid disease build-up. For beetles, leave some dead branches attached to living trees — these provide larval food and adult shelter. A pile of decaying woodchips or sawdust nearby will also attract specialist species. And resist the urge to tidy. Every fallen bough, every crumbling stump, is a micro-habitat. In a small wood or a large garden, you can create a mosaic of deadwood at different stages of decay, from fresh to fully rotted. That variety is what keeps the food web buzzing.

Staying safe and within the rules

Deadwood is only valuable if it is safe. Before leaving any standing dead tree, check for targets: footpaths, roads, buildings, fences and play areas. If there is any doubt, consult a qualified arboriculturist. In the UK, you may need permission for work on trees with a Tree Preservation Order or in a conservation area, and felling licences apply in some cases. Never create a hazard to save a stump. If a tree is unsafe, reduce it to a safe height and leave the rest. For log piles, avoid placing them against buildings or where they could be a fire risk. Finally, be patient. Deadwood habitats develop slowly. A fresh log pile may look quiet for a year or two, but within five to ten years it will be alive with beetles, fungi, solitary bees and overwintering insects. You are not just leaving wood to rot — you are building a woodland legacy.