The Corlea Trackway, an elevated wooden road about 2000 years old was discovered in Ireland, made of planks from Oak and Birch trees

a modern version of it

Raised wooden roads were commonly used as a way for people to cross bogs and marshy land.

The Corlea Trackway, is a corduroy road made of split planks that had been laid on top of raised rails.
Corlea is the largest togher discovered in Europe, spanning about one kilometer and is about three and a half meters wide. Three hundred large oak trees were felled to create the planks and about the same amount of birch was needed for the rails. This equates to about a thousand wagon-loads of construction material.

The Corlea Trackway leads to a small island that was excavated in 1957. A second togher about one kilometer long was on the other side of the island.

Like almost all trackways, it had sunk under its own weight into the bog in less than a decade, where it was preserved by the anaerobic conditions. To date, after being excavated, only about 18 meters of the original trackway still survives above water and can be seen at a visitor center in Kenagh

https://www.thevintagenews.com/2017/04/21/the-2000-year-old-corlea-trackway-a-wooden-road-in-ireland/
https://en.wikipedia.org/wiki/Corlea_Trackway