Kho Daeng forest - known as the country's most fertile source of Iron Wood trees - is poised to be registered as part of a national park, officials said.
Malacca Teak is among the world's most endangered wood species.
Following a tip-off by local residents that some people had cut down old trees in the forest without permission, officials and police inspected the area and found two stumps - one with a 3-metre radius and the other with 2-metre radius - near a pile of 178 planks.
A shack with basic cooking tools and some clothes was also found but no-one was in the area. Authorities suspect they had been tipped-off and fled.
It was suspected that the culprits were local people who wanted to use the planks to build a house.