Why the names matter
Pruning is not one operation. Australian Standard AS 4373-2007 defines a set of distinct ones, and asking for the right name gets you the right result and a comparable quote.
Ask for "a trim" and three operators will quote three different jobs. Ask for a crown reduction of two metres plus dead-wooding and they are all quoting the same thing.
Crown reduction
Reducing the overall height and spread by cutting branches back to a living lateral of adequate size - at least a third the diameter of the part removed. That lateral becomes the new terminal and the tree keeps a natural shape.
This is what people mean when they ask for a tree to be made smaller, and it is the legitimate alternative to topping. There are limits: you cannot reduce a tree by half and expect it to survive well. A reduction of one to two metres on a mature tree is usually sensible; four is usually not.
Crown thinning
Removing a proportion of the secondary branches evenly through the canopy so light and air get through, without altering the outline or height.
Useful under a dense canopy where nothing will grow, on a tree with fungal problems in a humid climate, and on top-heavy trees where reducing sail area lowers storm risk. Take no more than about 15 to 20 per cent of the live canopy in one go.
Crown lifting
Removing the lowest branches to create clearance underneath - for a car, a mower, a footpath or a roof. Straightforward, low-risk work on most species.
The caution is proportion: lifting too high leaves a tree with all its weight at the top and a long bare stem, which raises rather than lowers the failure risk.
Dead-wooding
Removing dead, dying and broken material. The highest-value safety work available and the one most likely to prevent an incident, because dead branches fall without warning and usually onto whatever is parked underneath.
On the Sunshine Coast the recurring dead-wooding species are hoop pine, eucalypt and old mango.
Formative pruning
Structural work on young trees: removing competing leaders, crossing branches and badly attached limbs before they become permanent.
The highest return on effort in all of arboriculture. Thirty seconds with secateurs on a three-year-old tree prevents the co-dominant stem failure that costs thousands to deal with in year thirty.
Restoration pruning
Rehabilitating a tree that has been previously topped or storm damaged. Over several seasons, the best-placed epicormic shoots are selected and the rest removed, gradually rebuilding a defensible structure.
It is slow and it never fully undoes the damage, but on a valuable tree it beats removal.
Pollarding
A maintained system rather than a single operation. Begun on a young tree, cut back to the same points on a regular cycle so knuckles of callus form. Common in Europe, uncommon here, and it only works if it is continued - an abandoned pollard becomes a hazard.
Choosing
Most real jobs are a combination: reduction plus dead-wooding, or lifting plus thinning. The technique guide explains where the cuts go, the timing guide covers when, and the benefits covers why it is worth paying for.
Frequently asked questions
What is crown reduction?
Crown reduction shortens the height and spread of a tree by cutting branches back to a suitable living lateral, one at least a third the diameter of the limb being removed. That lateral takes over as the new leader, so the tree keeps a natural outline and can seal the wound. It is the correct alternative to topping.
What is the difference between crown thinning and crown lifting?
Thinning removes a proportion of secondary branches throughout the canopy to let more light and wind through, without changing the tree's height or outline. Lifting removes the lowest branches to create clearance underneath - over a driveway, a path or a roof. They solve different problems and are often done together.
Is pollarding the same as topping?
No, although they look similar. Pollarding is a deliberate system begun on a young tree and repeated on a cycle, with cuts made at the same points each time so a knuckle of callus forms. Topping is a one-off cut through mature wood with no system behind it. Pollarding works because it is maintained; topping fails because it is not.
Which pruning type do I need?
If the tree is too tall or too wide, reduction. If it is too dense or too dark underneath, thinning. If you cannot walk or park under it, lifting. If there are dead branches, dead-wooding. If it is young and has two leaders, formative pruning. Most jobs are a combination of two.