[3.72] Burning standing trees

[Kreivos]

Pushing branches to a tile with a standing tree and setting them on fire seems to just burn the branches for the couple of minutes, but the tree disappears with the branches at the end of it, leaving just the embers. I wonder how this could be improved, as it's not really feasible to set a big standing tree on fire with just few twigs. Should the tree remain standing without damage or should there not be an option to set fire on a tile with a standing tree?