Rubberwood stumps and roots: from field burning to boiler fuel

When a rubber plantation is felled for replanting, the stumps and roots are usually piled and burned in the field. That is some of the best-burning wood on the tree going up in smoke for nothing.

Why stumps come out regardless

Growers do not dig stumps because they want to sell them. They dig because they have to. A stump left in the ground harbours white root disease, which spreads to the newly planted trees in the same field.

So the digging happens every replanting cycle and the cost is already paid. The only open question is whether what comes out goes to a bonfire or to an industrial furnace.

Stumps are better fuel than people assume

The wood in the stump and root collar is denser than branch wood, because it carried the weight of the tree for its whole life. Higher density means more heat per unit volume.

There is one condition that cannot be skipped: soil and stones have to come off before chipping.

A freshly dug stump has soil packed into the root crotches. Chip it as-is and that soil rides along into the fuel, becoming unnecessary ash and an abrasive that wears blades, furnace walls and conveyors.

This is why we screen every batch before it goes near the chipper. It is not an extra step — it is what makes stump wood saleable fuel at all.

Field burning against furnace burning

Both release the carbon the tree absorbed. Two things differ.

Particulate. Open burning has no air control, combusts incompletely, and emits fine particulate freely — part of Southern Thailand's dry-season air quality problem. An industrial furnace has combustion control and dust collection.

What you get back. A field fire produces smoke. A furnace produces steam or electricity that displaces coal.

Who gains

Growers earn from material they previously paid to dispose of, and clear the field faster for replanting.

Plants get feedstock tied to the replanting cycle, which can be forecast, rather than a seasonal residue.

Neighbours get less open burning.

What to ask before buying stump-derived fuel

• Is soil screened before chipping? If not, expect high ash and fast wear.
• What is the ash percentage? Ask for figures from delivered batches, not theory.
• How consistent is moisture? A freshly dug stump and one piled for months are very different.

We produce chips from rubberwood and mixed hardwood, screening foreign matter before processing every batch. Call +66 92 392 2292 or see the fuel comparison.