Why we build our fuelwood business around Acacia mangium
Heat value, ash, seasoning and supply consistency — the case for building a fuelwood line around a single named species.
Sri Lanka burns a great deal of wood. Tea factories, bakeries, brick and tile kilns, rubber driers and food processors all run on it. Yet most buyers are handed whatever mixed fuelwood a supplier happens to have that week, with no idea what species it is or how wet it was when it went on the truck. We built our fuelwood line around one species — Acacia mangium — and this note explains why.
The short answer
Acacia mangium grows fast in wet-zone hill country, produces a dense wood with a high heat value and low ash, splits cleanly, and seasons in a reasonable time. For a boiler operator, that combination means fewer deliveries per month, less de-ashing downtime, and a fuel whose behaviour does not change from load to load.
We hold 19,129 standing Acacia mangium trees across our estates, which is what allows us to offer the same species consistently rather than whatever is available.
What Acacia mangium actually is
Acacia mangium is a fast-growing tropical hardwood, widely planted across South and Southeast Asia. It thrives in exactly the conditions our estates sit in: high rainfall, acidic soils, warm year round. On a plantation rotation it reaches usable size in well under a decade, which is why it has become a mainstay of industrial fuelwood and pulp supply across the region.
It matters that this is plantation-grown timber, not natural-forest timber. Our harvesting rights come from Hapugastenne Plantations PLC, a Browns Group company, and every consignment is traceable to a named estate. For buyers who are asked by their own customers where their fuel comes from, that documentation is worth having.
How it compares on heat value
The number that matters to a boiler operator is net calorific value at the moisture you actually receive — not the oven-dry laboratory figure. The table below gives typical published ranges for fuelwood species commonly burnt in Sri Lanka, at roughly 20% moisture content.
| Species | Net calorific value | Air-dry density | Common use in Sri Lanka |
|---|---|---|---|
| Acacia mangium | 16–17 MJ/kg | 500–600 kg/m³ | Boiler fuel, kilns, driers |
| Eucalyptus (torelliana, grandis) | 16–18 MJ/kg | 550–700 kg/m³ | Boiler fuel, industrial firewood |
| Gliricidia sepium | 15–17 MJ/kg | 500–650 kg/m³ | Smallholder and estate fuelwood |
| Rubberwood (offcuts) | 15–16 MJ/kg | 500–600 kg/m³ | Boiler fuel, bakery ovens |
Figures are indicative published ranges for each species, not measurements of a specific consignment. Actual delivered values vary with moisture content, bark fraction and growing conditions.
Read across that table and the honest conclusion is that Acacia mangium is not dramatically hotter than the alternatives. Eucalyptus is comparable and denser. The case for Acacia is not that it wins on any single number — it is that it is consistently good across all of them, and available in the volume to supply the same thing every month.
A fuel that is slightly hotter but arrives as an unpredictable mixture is worth less to a boiler operator than a fuel that behaves the same way every week.
Ash, bark and what it does to your boiler
Heat value gets the attention; ash causes the headaches. High-ash fuel means more frequent de-ashing, more downtime, and in bad cases slagging on grate bars and heat-transfer surfaces. Acacia mangium is a low-ash fuel, which is a large part of why it is favoured for industrial use.
| Property | Acacia mangium, typical | Why it matters to you |
|---|---|---|
| Ash content | ~0.5–1.5% | Lower ash means less frequent de-ashing and less downtime |
| Moisture, freshly felled | 45–60% | Roughly half the weight you pay for would be water |
| Moisture, air-dried 3–6 months | 20–30% | The condition worth specifying when you order |
| Bark fraction | Moderate | Bark carries more ash and grit than clean wood |
| Splitting | Splits cleanly along the grain | Easier to size for a firebox; less hand-work on site |
Indicative ranges for the species. We can discuss the condition of a specific consignment when quoting.
Seasoning: the part buyers underestimate
Freshly felled Acacia can be half water by weight. Since firewood is sold by the tonne, buying green wood means paying timber rates for water — and then spending part of your fuel's own energy boiling that water off inside your furnace before it does any useful work.
Air-drying under cover for three to six months brings moisture down towards 20–30%. The difference in usable heat per tonne is substantial, and it is the single biggest lever on what your fuel actually costs you. We cover the arithmetic in detail in our guide on how firewood is priced and weighed.
Why this suits Sri Lankan industry specifically
Our estates sit in the Ratnapura District, in the wet zone. That puts us close to the tea factories of Sabaragamuwa and within straightforward road haulage of Colombo, Avissawella, Kegalle and the Western Province industrial belt. For a buyer, short haulage means a smaller transport component in the delivered price and more reliable scheduling in monsoon months.
It also means we can offer standing contracts rather than spot loads. A tea factory that needs a predictable tonnage every month is better served by a supplier who can commit to the same species from the same estates for a year than by whoever is cheapest this week.
What we supply
Plantation-grown Acacia mangium fuelwood, harvested across our six estates in the Ratnapura District.
- Species Acacia mangium
- Standing resource 19,129 trees
- Sold by Weight — metric tonne (MT)
- Form Logs or split firewood, sized to order
- Condition Green or air-dried — specify when ordering
- Weighing Certified weighbridge, ticket with every load
- Terms Ex-depot standard; delivery quoted island-wide
- Documentation VAT invoice and timber transport permits