Two different jobs
Once a tree is down you are left with a stump, and there are two ways to deal with it. They are not variations of the same service.
Stump grinding uses a machine with a rotating carbide wheel to chew the stump and the top of the buttress roots out to roughly 250 to 350mm below the surface. The lateral roots stay in the ground and rot away over years.
Stump removal excavates the stump and the root plate entirely, usually with a mini excavator, cutting major roots as they are exposed. It leaves a large hole which is then backfilled and compacted.
Which one you need
Grinding is right for almost all garden situations. Turf over the top, a garden bed, paving, a path — grinding to normal depth is enough for all of them and costs a fraction of excavation.
Full removal is right when something structural is going over or near the old trunk position. Slabs, strip footings, piers, retaining walls, pool shells. Buried timber decays and leaves voids, and voids under structural loads cause settlement years later. Your engineer or certifier will usually specify it, so ask them before you book anything, because if grinding is acceptable you save a lot.
The other cases are trenching new services through the old root zone, and persistent suckering from lateral roots on species that do it — privet, camphor laurel, poplar.
Do it on the same day
This is the easiest saving available on a tree job. A grinder has to be floated in on a trailer, and that mobilisation is charged whether the machine works for twenty minutes or four hours. Doing the stump on the same visit as the removal pays for it once instead of twice.
The catch is access. Occasionally the grinder needs a different route in from the tipper, or the ground is too soft after rain, and then it genuinely is two visits.
What the North Shore ground does to a grind
Across Hornsby, Lane Cove, Riverview and the sandstone gullies, Hawkesbury sandstone sits close to the surface and a grinder tooth that finds rock at 200mm cannot go deeper. That is a physical limit, not a shortcut, and it should be flagged in the quote rather than discovered afterwards. On the shale ridge through Gordon, Pymble and St Ives the soil is deep and the grinding is clean — but the stumps are much bigger.
Old fill is the other problem, particularly on the river flats around Meadowbank and Ryde, where buried brick and concrete destroy grinder teeth.
Before the machine starts
Tell the crew what is buried: irrigation, garden lighting cable, old terracotta sewer, stormwater. You know your garden and they do not. The cost guide explains the pricing drivers. Ring (02) 9090 4915, or read more on the blog.
Frequently asked questions
Can I just leave the stump?
You can, and plenty of people do. A stump in a back corner that is not in the way and not near the house is a slow, harmless decay process and eventually habitat. The reasons to deal with it are trip hazard, mowing, termite attraction close to a building, persistent suckering on species like privet and camphor laurel, and landscaping plans.
How long before I can plant where the stump was?
Turf can go down once the backfill has been topped up and settled, usually a few weeks. For a replacement tree, plant at least a metre away from the old trunk position — the ground there will be full of wood chip for a season or two, which ties up nitrogen as it breaks down and makes a poor start for a new tree.