Prune or Remove a Tree? How to Decide

Prune first when the problem is in the branches; remove when the problem is in the trunk or the roots.

You are standing at the bottom of the garden with a ladder you have not moved in ten minutes, looking up at a limb that hangs over the kitchen. The answer is usually decided by where the defect sits. If the trouble is a branch, a crossing limb or a heavy end that overhangs a roof, pruning can solve it and the tree stays. If the trouble is the trunk, the root plate or the whole canopy structure, no cut in the branches fixes it and removal is the sensible call.

That single split answers most of the question. Everything below is how to work out which side of it your tree falls on, and what a crew has to do differently in each case.

• Branch problem: prune. Deadwood, a split fork, a limb rubbing the roof, a low branch over the drive.
• Trunk or root problem: remove. A hollow base, a crack running up the stem, mushrooms at the soil line, a trunk that has started to lean.
• Both at once: the tree is usually a removal, because you cannot prune your way out of a failing base.
• Not sure which one you have: describe what you see over the phone, then have it looked at before anything is cut.

What does pruning fix?

Pruning fixes clearance, weight and dead tissue. It is the right tool when a limb is too close to a roof, a driveway or a power drop, when a fork has split and one side is hanging, or when dead wood is sitting over a path where it will eventually fall on its own.

A proper pruning cut is made at the branch collar, the slight swelling where the limb meets the parent stem. Cut flush into that swelling and you remove the tree's own sealing tissue; leave a stub and the wound cannot close over. Both mistakes leave an opening that decay moves into, and decay is how a branch problem slowly becomes a trunk problem.

How much can come off before it stops being pruning?

As a working rule, a healthy mature tree tolerates roughly a quarter of its live canopy in one visit, and less than that if it is old, stressed or already declining. Cross that line often and you get the opposite of what you wanted: the tree pushes out fast, weakly attached shoots from the cut points, and you are back on the ladder in a few seasons.

Pruning is also the cheaper option in most cases, but the number depends on height, access, how much has to come off, and whether the wood can be dropped or has to be rigged down in sections over something you want kept intact. That figure needs an on-site estimate.

When a tree has to come down instead

A tree has to come down when the failure is structural and cannot be cut away. The clearest signs are a hollow or soft base, a vertical crack in the trunk, conks or mushrooms growing out of the stem or the soil line, a root plate that has lifted the ground around it, and any lean that has appeared recently rather than being the tree's original shape.

There is a difference between a tree that has always grown at an angle and one that has started to move. A tree that has leaned for thirty years is usually holding. A tree that leaned during the last storm, with fresh soil pushed up on one side of the base, is a tree whose roots have already lost their grip. That is the one to keep people away from until it is down.

Removal is not one job. A tree with open ground all around it can be felled in one piece. A tree hemmed in by a fence, a shed, a driveway or a neighbour's property has to be taken down in sections, with each piece roped and lowered rather than dropped. That difference in method, not the height alone, is what makes two trees of the same size cost very different amounts.

Can a tree be removed without wrecking the lawn?

Yes, with rigging and ground protection. Sections are lowered on ropes to a controlled drop zone, and mats or plywood spread the load of the machinery. It takes longer than a straight fell, and that time is part of what you are paying for.

Check these before you decide

Walk the tree once from a safe distance and once from the base, and look for the following. Anything in the first group points to pruning; anything in the second points to removal.

• Dead branches with no buds or leaves in season
• One limb crossing and rubbing against another
• Branches within a few feet of the roof, the siding or the power drop
• A split fork where one side is still attached
• Water sprouts shooting up the trunk after earlier cutting
• A hollow you can see into at the base
• A crack running lengthwise up the trunk
• Fungal growth at the base or on the stem
• Soil pushed up or cracked on one side of the trunk
• A lean that is new, or that has got worse since last year
• Bare soil or exposed roots where the ground has eroded

Two or three items from the second list together is not a pruning job. One item from the second list on its own still needs eyes on it, because a hollow that looks small from the outside can be most of the trunk.

How urgent is it?

Urgency tracks what the tree would hit, not how ugly it looks. A dead limb over an empty back corner can wait for a scheduled visit. The same limb over a driveway, a footpath or a child's swing set moves up the list.

• Watch: deadwood over open ground, a low branch over a bed, water sprouts after old cuts. Get it on a list and have it looked at when convenient.
• Soon: a limb resting on a roof, a split fork still hanging, a hollow base with no lean. Book the work before the next heavy wind or snow load.
• Now: a fresh lean with lifted soil, a crack that has opened in the last storm, a limb already on a structure, or a trunk that has shifted off vertical. Keep people and vehicles clear and treat it as a job for someone working from the ground and with ropes, not a ladder.

If a limb is already on a roof or a car, do not climb up to it and do not stand under the part still attached. Move people back, and let the load be taken off in a controlled way.

What to ask before any cut is made

Ask what the tree is expected to do after the work, and ask it in plain words: will this tree be safer, and for how long? A pruning job on a declining tree buys time, not a permanent fix, and you should hear that before the saw starts rather than after.

Ask how much live canopy is coming off, and ask where the cuts will be made. Ask whether the wood is being dropped or rigged down, because that is the part that changes the labour and the price. Ask what happens to the debris, since removal of the wood and brush is a separate task from the cutting itself. Ask for the figure in writing, with what is included spelled out, and ask what happens if something unexpected turns up once the tree is opened, such as a hollow that was not visible from the ground.

If the answer to any of those is vague, ask again. A tree is not a thing you get to redo next season.