How do I create a loot table that gives nothing sometimes? (2023.3, Forge, 1.20.1)

I'm trying to add a tree, but I hit a roadblock.. the leaves drop items way too often. I can't figure out how to make the loot table only drop items sometimes. I tried adding an 'air' drop, and giving it a higher weight than anything else, but when I saved the loot table, the air was removed.