I downloaded one of the tree asset packs to use with placing trees on the terrain editor. But if I place a tree on the terrain, the tree is gigantic in scale. I adjusted the scale of the original prefab to .01 and then placed that onto to the scene and it resized properly. But when I added it as a tree in the terrain editor it still placed the tree at a gigantic scale. The tree height/width sliders make no difference to the scale either.
Select the tree either in the scene window or the hierarchy window, Then it will show up in the “Inspector” window, where you should see an option to scale the tree on both the x,y and, z axis.