Wingnut used to sell caramelized bamboo, I bought a bunch of these slats back in the day. They made great bow backings, very high performance.
The slats were sold as Tonkin bamboo but Tonkin doesn't get over 3" in diameter, these slats were from very big bamboo but obviously caramelized, good stuff.
A friend offered to cut me a bunch of bamboo the other day, I asked for a picture of the patch. It was big stuff but the nodes were very close together, no more than 8 to 10" apart. I passed on the deal because of the node spacing.
I prefer this type of node spacing, about 2 ft. This is Giant timber bamboo.