My tree is leaning after a storm — what should I do?

Trees lean for two very different reasons. Many have leaned all their lives, growing away from shade or into the light, and have laid down reaction wood to compensate — those are usually stable. A tree that has moved suddenly is a different thing entirely, because the root plate has been broken and the tree is now held up by less than it was. Telling them apart is done at ground level, not by looking at the trunk.

Safety

What you'll need

• Binoculars
• A camera
• Hazard tape or something to cordon with (optional)

Step by step

1. Keep everyone away first, and assess from a distance.Set the exclusion zone at the tree's full height in every direction. Move cars. Keep children and pets out. Do this before you start investigating anything.
2. Check for power lines before anything else.If any part of the tree is near or touching an overhead line, do not approach it and do not let anyone else. Ring the electricity network operator's emergency number immediately — it is a free 24-hour service and they will attend.
3. Look at the ground on the side opposite the lean.This is the diagnostic. Soil cracked, heaved into a ridge, or lifted with roots showing means the root plate has rotated and the tree is actively failing. That is an emergency, not a job to think about at the weekend.
4. Look at the base on the side of the lean.A gap opening between the trunk base and the soil, or soil compressed and bulging, is the other half of the same picture.
5. Judge whether the lean is new.Old leans usually show a curved trunk that has grown back towards vertical, established undisturbed ground and vegetation at the base, and bark that is not stretched or split. A new lean is straight, with disturbed ground and often torn roots.
6. Look for cracks in the trunk and torn roots.Vertical splits, a bulge on the compression side, or roots visibly snapped at the edge of the plate all indicate structural failure in progress.
7. Photograph everything, dated.For the arboriculturist, for the insurer, and for the council if the tree is protected. Take wide shots showing the lean and close shots of the ground and the base.
8. Ring an arboriculturist, and say it is urgent.Most firms keep emergency capacity after storms. Describe what you have seen at the base — that is what determines how quickly they come.
9. Do not prop, wire or pull it.A leaning tree contains an enormous amount of stored energy and a partially failed root plate. Attempts to winch, prop or tie it are dangerous and can trigger the failure. Leave it to people with the equipment and the training.
10. Tell the neighbours and, if relevant, the council.If the tree could fall onto a neighbour's property, tell them in writing straight away — it protects them and it establishes that you acted. If it overhangs a road or footpath, tell the highway authority. If it is protected, there are emergency exemptions but the council should be told as soon as possible, ideally before the work.
11. Check your insurance position.Storm damage to trees themselves is often excluded from buildings policies, but damage caused by a falling tree is usually covered. Photographs and a written record of what you did and when will matter if a claim follows.

Tips

• Newly planted trees that lean after wind can often be straightened and re-staked in the first couple of years. Mature trees cannot.
• A leaning tree that has stood for years with sound ground at the base is generally not the emergency people fear. The ground is the evidence, not the angle.
• Waterlogged ground after prolonged rain is when root plates fail. Check trees after a wet, windy spell, not only after a named storm.

Common mistakes

• Judging danger by how much it leans — Angle alone means little. A 20-degree lean on a tree that has always grown that way is fine; a five-degree new lean with heaved ground is critical.
• Trying to winch it upright — The root plate is already broken. Applying force is dangerous to the person doing it and usually completes the failure.
• Waiting to see if it settles — A partially failed root plate does not repair. The next wind finishes it, and by then it may have your car or your neighbour's roof underneath it.
• Approaching a tree near a power line — Electricity arcs and wet timber conducts. Keep back and ring the network operator.

If it doesn't work

Questions people ask