I also don't know where they got the 11ka from? From the paper: The earliest known wood artefact is a fragment of polished plank from the Acheulean site o

I also don't know where they got the 11ka from? From the paper: The earliest known wood artefact is a fragment of polished plank from the Acheulean site of Gesher Benot Ya’aqov, Israel, more than 780 ka (refs. 2,3). Wooden tools for foraging and hunting appear 400 ka in Europe, China and possibly Africa. At Kalambo we also recovered four wood tools from 390 ka to 324 ka, including a wedge, digging stick, cut log and notched branch. So not exactly much, but there are other finds. But the problem is to not only find wood that is that old and has survived and has (clear) signs of human "tools", but had also been used for "structural" purposes. I also don't understand the general idea. So there are humans capable of generating tools out of stones (the oldest flint tools are 3 millions of years old), but the idea that they use these tools to work wood to help making something structural out of wood - like some notches to be able to easier put some sticks of wood together - is debatable? The problem for archeologists is of course to prove that these wooden "structures" existed by, well, finding traces(Oh, what a pun!) of them.