When optifine is installed the transparent part of the leaf texture renders green instead of black on fast graphics. I looked into this a while ago as Twilight Forest was for some reason the only mod immune to this and i found that to fix this the leaf texture must be the vanilla one. Not copying the texture, literally using the texture from the minecraft assets in the model path. I reported this to optifine twice but got no response after years. It looks like the TFC textures arent vanilla so a different fix will have to be found. This bug is quite annoying as 1.12 is a lot laggier than 1.7 without having to turn on fancy graphics.

Not supporting optifine, you're on your own there. I'd assume this is due to the way we handle #753 and if such we aren't changing that because it's caused all manner of headache on it's own and the fix for which is dodgy at best.

its unrelated to 753. fruit trees still look like that too but for a different reason.