Export pallet lumber needs two things: kiln drying (KD), which removes water and prevents mould in the container, and heat treatment (HT) under ISPM 15, which kills pests and qualifies the wood for the IPPC mark checked at the destination port. One does not replace the other. For pallets that travel by sea, the right order is KD-HT lumber.
What kiln dried (KD) lumber means
Kiln dried wood is lumber dried in a kiln, not in the open air. Freshly sawn lumber is full of water, often more than half its weight. In the kiln, heat, airflow and controlled humidity take that water out until the wood reaches the agreed moisture content.
Under North American grading rules, lumber stamped KD has a moisture content of 19% or less. For pallets, that matters for three reasons:
- Mould and fungi. Wet wood in a closed container crossing an ocean releases water that condenses on the walls and the cargo. Below roughly 20% moisture, fungi do not have the conditions to grow.
- Stability. Wood that dries after assembly shrinks and warps. Nails loosen and the pallet loses strength.
- Weight and freight. Less water means less weight per cubic metre. More wood fits on the truck and freight per piece goes down.
What heat treated (HT) lumber means under ISPM 15
HT stands for heat treated. Heat treated wood has been heated to kill pests: insects and larvae that can travel inside wood from one country to another.
ISPM 15 is the international standard for wood packaging material in trade. It requires the core of every piece to reach 56 °C and stay there for 30 continuous minutes. Once treated, the wood carries the IPPC mark (the wheat-ear stamp), which customs at the destination checks. Without it, a pallet can be refused, sent back or destroyed, along with the delay to the cargo on it.
KD-HT: both in the same load
The two usually go together, but one does not guarantee the other. Wood can be HT without being dry (the treatment is short), and it can be dry without an HT record. For export pallets, ask for KD-HT: dried to the right moisture content and with the heat treatment recorded.
Lumber grade matters too
Dry and treated, the lumber still has to match the grade your line can take: how many knots, how much blue stain and wane (the rounded log edge) each piece can have. Export buyers mostly take A and B grades. We explain each one in pine lumber grades explained.
What to check in a pallet lumber supplier
- Own, controlled kilns. Ask how moisture is measured and whether every cycle is recorded.
- HT records. The treatment must be carried out by an authorised provider, with a time and temperature record for each load.
- Moisture at delivery, not only at the kiln door. Dry lumber left in the rain gets wet again.
- Consistent dimensions. Pallets are built on machines or jigs; off-size boards stop the line.
- Origin. Plantation pine, FSC® certified when your customer requires it.
How LG Madeiras does it
LG has run its own kilns since 2017. Drying is controlled by Marrari’s EcoPower MR500 system, which reads wood moisture in real time, adjusts the kiln automatically and records every cycle. Our lumber leaves the kiln at 5% to 12% moisture content, well below the 19% KD limit.
In 2023 our kiln was audited and approved under the heat treatment programme of Timber Products Inspection (TPI), accredited by the American Lumber Standard Committee (ALSC), and we keep the same temperature, time and record controls on every load.
Our sawn pine lumber leaves the mill in Ituporanga, Santa Catarina, for pallet and packaging manufacturers in Brazil and, in containers, through the ports of Itajaí and Navegantes.
Sources: ISPM 15 (IPPC), the lumber marking rules of the American Lumber Standard Committee (ALSC) and the Wood Handbook (USDA Forest Products Laboratory), on moisture and decay.