Two different kinds of waste wood mulching
Waste wood handling involves more than picking the biggest possible machine and making the non-merchantable slash and debris go away. One of the first decisions to make for your project is: Do we want subsoiling or surface mulching?
Surface Mulching
If you’ve seen the work that mulchers do, you’ve seen the result of surface mulching: waste wood is reduced to small pieces in the powered head of a mulcher and is spread through the work area. At high speed, woody debris is pulled through a rotating drum equipped with teeth that chews up large chunks of wood into the characteristic mulch that mulchers are known for.
With surface mulching, the head of the mulcher machine rides on the ground surface and follows the local contours. The top layer of soil is slightly disturbed as it works, but a surface mulcher only handles the material that is sitting on top of the ground surface. The resulting mulch also remains on top of the soil.
Subsoil Mulching (or Subsoiling)
Subsoiling is a much different process. Subsoiling mulchers, like the IronWolf 1040, have the power and design to place the mulching head below the soil surface. Placing the mulching head into the soil does several key things:
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- The mulch is mixed into the soil
- Roots, stumps, and waste wood that is embedded in the ground become part of the mulch product
- The soil is loosened and aerated
The much higher load placed on the mulching head means much more power is required to drive it, so subsoiling mulchers are typically 600hp+ class machines.
Why Choose Subsoiling over Surface Mulching?
Subsoiling makes sense for your project when:
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- You will need to strip the soils away for grading/earthwork – the soil is loosened (especially important for frozen soils) and is ready to be moved by earthmoving machines
- You need to grub out roots, for soil stripping or to control the regrowth of suckering species of brush and trees
- You want to incorporate the mulch pieces into the soil, for wildfire risk reduction or to accelerate natural decomposition
Surface mulching makes more sense when:
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- Slope stability concerns mean you want to keep root systems in place
- Soil horizons are very shallow and you want to prevent any mixing
- Soil conditions are so soft that only the lowest ground-pressure machines should be used
There’s nothing wrong with combining the methods either – use the best method for each part of your project for the best results.
Let EM3’s vast project experience help you explore options for your next job – reach out to us for a consultation
