Police said the accident happened on a road in Ban Khuan Sawang village in Tambon Sai Khueng.
The truck driver was identified as Eng Muangkaew, 44.
Police said the driver was killed behind the wheel after the trailer cab, which was loaded with minerals, was crushed in the collision.
Witnesses told police they saw a motorcycle cut into the front of the truck, causing the driver to try to stop, but the momentum caused the truck to hit the rear of a pickup in front of it before crashing into the tree.