As stated, KD (kild dried) lumber has had is moisture content reduced in a very controlled fashion. It is done with heat, humidity, and quite a bit of science. Done incorrectly you can cause the wood to bend, twist, check, cup, and lose its color.
Nearly all hardwood flooring and lumber for woodworking must be kiln dried, or air-dried over many many months. Your climate and humidity level in vietnam is not conducive to air-drying lumber to acceptable levels I imagne. Most hardwoods are dried to between 6-12% moisture content for use in woodworking and millwork.
Technically, kiln-drying is achieved at 19%, but that's still too wet for interior millwork and furniture applications in my opinion.
If you're an exporter, you probably have dealt with HT (heat treated) lumber as well. HT is often required to kill organisms in the wood before it is shipped to other parts of the world. It is not the same as kiln drying.