Crocodile Hunter

Salams

I was watching crocodile hunter (Steve Irwin) last night and they went to Eglin Rangers **** and helped with them to take out dangerous species which would conflict with their training so he steve entered this tunnel made with wood and strong timber to show us how the bats live there.

these tunnels were created in the Vietnam War and are pretty strong but i wanna ask...so many years have passed, dont the termite or the insect that eats woods have eaten the tunnel away when its like deserted for many years?

or is there a certain wood that termite dont eats? thanks