Forestry mulchers and flail mowers both fit on an excavator and both shred growth where it stands, so they're easy to confuse. They're built for different work. A flail mower cuts grass, brambles and hedges, and a forestry mulcher shreds trees, scrub and dense vegetation. Here's how each one works, what each cuts, and how to choose.
The Short Answer
- Choose a flail mower for banks, verges, ditch sides and hedges, and growth up to 80mm thick on our largest flail.
- Choose a forestry mulcher for clearing scrub, saplings, small trees and dense vegetation, leaving a layer of mulch instead of brash to burn or haul away.
How Each One Works
A flail mower has a horizontal rotor fitted with rows of blades, driven by a direct drive hydraulic motor. Our smaller flails use Y-blades for grass and lighter growth, and the larger ones use heavier hammer blades. A self-levelling head and a height-adjustable roller follow the ground for an even cut.
A forestry mulcher head spins a heavy rotor, fitted with rollaway forged hammer blades or fixed teeth, on a Hardox® 400 shaft. On our FMH heads, a piston motor drives the rotor through belts, two counter-blades help shred the material, and a flap at the front of the frame controls the material. The flap is manual on the 5 to 10 tonne head and hydraulic on the larger two.
Side by Side
| Excavator flail mowers | Excavator forestry mulchers | |
|---|---|---|
| Built for | Grass, brambles, scrub and hedges | Trees, hedgerows, scrub and dense vegetation |
| Thickest material | 20mm (Y-blades), 40mm or 80mm (hammer blades) | Trees and dense growth |
| Excavator size | 0.8 to 10 tonnes | 5 to 25 tonnes |
| Working width | 600mm to 1500mm | 800mm to 1600mm |
| Cutting tools | Y-blades or hammer blades | Rollaway hammers or fixed teeth |
| Hydraulics | 15 to 80 l/min, two hoses, no drain line | Confirmed for your machine before supply, hoses and fittings included |
When a Flail Mower Is the Better Choice
If you're mostly cutting back growth, a flail is the right tool. It suits regular maintenance of banks, verges, ditch sides, field margins and hedges, and it comes in sizes for micro and mini diggers, which our mulchers don't. The 3 to 7 tonne flail cuts up to 40mm and the 5 to 10 tonne flail cuts up to 80mm. Read how to use an excavator flail mower for set-up and cutting technique.
When You Need a Forestry Mulcher
If the job is clearing land rather than maintaining it, choose a mulcher. It shreds scrub, saplings and small trees where they stand, so there's no pile of brash to burn or take away. Our three heads cover 5 to 25 tonne excavators:
- 5 to 10 tonne forestry mulcher: 800mm or 1000mm wide, rollaway hammers or fixed teeth, manual flap
- 9 to 15 tonne forestry mulcher: 1050mm or 1300mm wide, rollaway hammers or fixed teeth, hydraulic flap
- 15 to 25 tonne forestry mulcher: 1050mm, 1300mm or 1600mm wide, rollaway hammers, hydraulic flap
What About Bigger Trees?
For single trees and bigger stems, an excavator tree shear cuts stems up to 450mm and holds each one so you can lay it on the pile. Read how to use an excavator tree shear. To clear roots and brash afterwards, use a root rake. Our guide on how to clear overgrown land with an excavator covers planning a full clearance job.
Check the Rules Before You Start
- Felling licence. In England, you need a felling licence to fell more than 5 cubic metres of growing trees in any calendar quarter, and you can sell up to 2 of those 5 cubic metres. It applies to trees with an over bark diameter of 8cm or more, or 15cm or more for coppice or underwood. There are exceptions, for example to prevent danger, but you must be able to prove any exception you rely on, and felling without a licence when one is needed is an offence.
- Protected trees. If a tree has a Tree Preservation Order, you need the council's written consent to cut it down, top, lop or uproot it. In a conservation area, you must give the council six weeks' notice before certain work on trees.
- Hedgerows. In England, hedgerows on or next to agricultural land can't be cut or trimmed from 1 March to 31 August unless an exception applies. See the government guidance on hedgerow management.
- Nesting birds. It's an offence to damage or destroy an active bird's nest, so check hedges, scrub and trees before you start.
Rules differ in Scotland, Wales and Northern Ireland, so check with the relevant authority there.
Working Safely
Both heads can throw stones, wood and debris, so keep everyone well clear of the working area. Walk the ground first for wire, fencing, stones and other hidden objects that could damage the rotor or be thrown out.
Hydraulics and Fitment
Match the head to your excavator's operating weight first, then its auxiliary oil flow and pressure. Each flail product page lists the flow it needs. For a mulcher, send us your machine make and model, its auxiliary flow and pressure, and your quick hitch or pin details, and we'll confirm the right head before it's supplied. Our guide on how to measure an excavator for a new bucket shows how to take the pin measurements.
Mulcher vs Flail FAQs
Can a flail mower cut small trees?
Only small saplings and growth up to the flail's limit, which is 80mm on our 5 to 10 tonne flail. For trees, use a forestry mulcher or a tree shear.
What size excavator do I need for a forestry mulcher?
Our mulcher heads start at 5 tonnes: the 5 to 10 tonne head, the 9 to 15 tonne head and the 15 to 25 tonne head. For smaller machines, a flail mower is the better fit.
Rollaway hammers or fixed teeth?
The 5 to 10 and 9 to 15 tonne heads come with either. Tell us what you'll be clearing and we'll help you choose.
Do I need permission to clear trees?
Possibly. Check whether you need a felling licence, whether any trees have a Tree Preservation Order or sit in a conservation area, and keep to the hedge cutting dates.
Compare our excavator mulchers and excavator flail mowers, or browse all our excavator attachments. Send us your machine details and we'll confirm the right head.
