Forest brush doesn't work

Or maybe I'm stupid and do something wrong? It doesn't create any trees. I've tried various kinds of trees and foliage and it only draws a floor

https://preview.redd.it/ecmgroonckyg1.png?width=446&format=png&auto=webp&s=2076e172aaf2d97ba0e602579820816068cfafd7

https://preview.redd.it/7ngwqfxkckyg1.png?width=1465&format=png&auto=webp&s=4b43201112785793176757a30d0044ad3979f42e