At what extent do elves care for Blood Thorn?

[Arson]

I've read some very criminally misleading text on DF wiki, saying that even elves don't care for blood thorn wood, and on some other web resource, that they don't count chopping blood thorns as chopping wood. I've created named wood farm, and made cages from it, to sell elves some animal in, but they suddenly got offended by such criminal act and stopped trading. I want to ask, where is real and official information on elves policies, since there are almost no real info I could find on this matter, and as I've said, wiki is straightforward wrong and misleading?

[Fel]

For chopping they definitely care about underground trees.
https://dwarffortresswiki.org/index.php/Elf#Diplomats

For trading on the other hand all woods are included except "grown" wood items (items made from grown wood logs are not acceptable either).
https://dwarffortresswiki.org/index.php/Trading#Unacceptable_items