Why a small garden needs deadwood

Deadwood is not untidiness. In a healthy wood, a good quarter of the timber lying about is standing dead, fallen or quietly rotting, and thousands of British species depend on it — beetles, fungi, solitary bees, hoverflies, mosses, even bats roosting behind loose bark. Most of that has been tidied out of our gardens over the last century. A single log pile can restore a surprising amount of it.

The good news is that deadwood habitat scales down beautifully. You need a patch about a metre square, a few pieces of untreated timber, and a willingness to leave them alone.

What to use, and what to avoid

Almost any untreated, unpainted timber will do, but variety speeds things up. A mix of species and diameters rots at different rates, and each stage of decay suits different creatures.

• Logs: 10–30cm across and 30–60cm long are ideal — large enough to hold moisture through a dry summer, small enough to move by hand.
• Branches and twigs: quick to rot and valuable for smaller beetles, woodlice and fungi. Pile them loosely rather than compacting them.
• Species: oak, beech, ash, birch, apple, cherry, willow and elder each bring something different. Softwoods such as pine rot slowly, which is fine too.
• Avoid: timber treated with preservative, creosoted, painted or stained, and any manufactured board. These offer little and can leach chemicals.
• Source: use what is already in your garden or comes from a local tree surgeon. Do not move oak or ash long distances — ash dieback and oak processionary moth travel with timber.

Aim for one to three cubic metres in total, though a wheelbarrow-load is a genuine start. If space is very tight, a dead hedge — two rows of stakes with prunings packed between — works in a narrow strip.

Building a pile that works

Position matters more than construction. Put most of your deadwood in shade or half-shade, where it stays damp — under a hedge, behind a shed, along a north-facing fence. Keep a smaller pile in sun for invertebrates that like to bask; warm, dry wood hosts a different cast again.

• Set a few logs half into the soil, or weigh them down so they sit in contact with damp ground. That contact is what lets moisture and fungal threads wick up into the wood.
• Stack the rest loosely, with gaps and a handful of twigs or leaves stuffed between. Airtight stacks go sour and support less life.
• Keep the heap below chest height and stable. Do not build it over a drain, on a main path, or anywhere it might slump onto someone.
• Leave at least 30cm between the pile and any shed, fence or house wall. It makes no difference to the wildlife and keeps damp — and neighbours — out of the equation.
• Push two or three upright, part-buried pieces through the heap. They rot from the base upward, creating the cool, crumbly heart that many beetle larvae need.

Standing stumps and solitary bees

If a tree has to come down, leave the stump 60–150cm tall rather than grinding it out. Standing deadwood dries on the outside while rotting within, and it is used by creatures that seldom touch a pile on the ground.

Old stumps and logs are also nesting real estate. Many solitary bees, including mason and leafcutter bees, nest in existing beetle exit holes, so simply leaving old wood alone helps. You can lend a hand:

• Drill holes 6–10mm across and 8–12cm deep into a dry stump or log, angled very slightly upward so rain drains out instead of pooling.
• Space them a couple of centimetres apart, and skip bamboo canes — they hold damp and turn mouldy.
• Saw the top of a standing stump at a slight angle so water runs off rather than sitting on the cut face.

Leave ivy to scramble over a stump if it wants to. It hides nothing harmful and adds another layer of shelter.

Fungi, moss and the slow work of decay

The first year or two can look slow. Then, usually after a wet autumn, you will find jelly ear on elder, dead man's fingers pushing up from buried wood, and brackets such as turkey tail spreading across a log. These are the recyclers: fungi break down lignin and cellulose, softening the timber so millipedes, woodlice and beetle larvae can follow. Some, like the sulphur polypore that stains oak a startling egg-yellow, are genuinely spectacular. Leave every one of them in place — identifying mushrooms for the pot is work for an expert, and the garden gains far more from the fungus than the kitchen would.

Mosses, liverworts and ferns will colonise the damp, shaded side. That is a sign the whole thing is working.

Looking after it through the year

Which is to say: mostly, don't. The main job is timing your tidying.

• Add new material in autumn, when the pile is active and there is rain to settle it in.
• Do not turn or move a pile in winter. Hedgehogs, toads, slow worms, newts and hibernating queen bees all use deadwood, and a midwinter fork through the middle is fatal for them.
• If you must move or top up the heap, do it in late spring or early summer on a mild day. Lift pieces slowly, leave them a few minutes so anything underneath can escape, and rebuild roughly as it was.
• Keep the leaf litter around the base. A rake-free corner beside a log pile is one of the richest habitats a small garden can hold.
• Check stability once a year, especially after gales, and rebuild anything that has started to lean.

Nothing here needs buying and nothing needs doing in a hurry. Set aside a corner, stack it roughly, and let the beetles, bees and fungi find it. In a small garden, that is usually the most generous thing you can do for wildlife — and the cheapest.