How to gradually decrease scatter density as altitude goes up (PCG)?

I have a PCG graph to spawn different tree meshes. I managed to control the minimum and maximum altitude where they can spawn. But the problem is that the limits are very abrupt and don’t appear gradual.

I’m sure there’s definitely a way to make the max and min transition more gradual, I just have no idea since I’m extremely new to unreal engine, let alone PCG.

PCG graph nodes (seperated in 2 parts so it’s easier to read)