Is it possible to make custom trees (custom shapes) with 1.15?

I'm told that using structures for trees only works with 1.16 in Mcreator, but I don't want to believe that it's true, so I wanted to confirm this. Can it be done in some way? Coding or not? Thank you for your replies. If it's only possible for 1.16 do you think we could get this is the next update (support for custom built trees in 1.15.2?) Thanks!