i couldn't use a grass block because i cant make it upside down, i like to use the barrier because there invisible
Step 1: How to Build an Upside Landscape
In this tutorial, I will teach you how to build an upside down tree with a chicken!
Step 2: Building the Platform
First, you want to make 7x7 dirt platform.
Step 3: Now to Build a Tree on the Platform
First plant a tree then copy it under the the platform
Step 4: Invisible Blocks
Do "/give <your username here> barrier" to get the barrier. with the barrier you place a 7x7 platform 2 blocks below the dirt platform
Step 5: Upside Down Chicken
get a name tag and with an anvil name the name tag 'Dinnerbone', then spawn a chicken under the dirt platform, then right click it with the name tag.