Onagers, Trebuchets, etc. don't destroy trees [256x]

I did my first forest nothing w/ 256x playing as Ethiopians. Had to try the nuke. However, sadness struck when I found that I became unable to destroy trees early on in the game. Does anyone know which tech broke it? I could increase range but none of the siege was destroying trees. I forgot to check if siege damaged buildings after the tree problem.