John Alcatraz reply had this image on the answerhub:
The important part is the Tesselation Multiplier connection, which tells the rendering pipeline how much the triangles have to be tesselated. Since the calculus use the current camera’s world position the nearby triangles around the camera will be split up using a high Tesselation Multiplier, and in the distance this TMultiplier goes down to 0, where no tesselation will happen. Imagine a radial gradient fade which will be applied on the landscape around the camera.
I’ll update my engine soon to be 4.13 so i can test this on a landscape but if you see there’s a bug that you can reproduce in 4.13 maybe you should open a file on the answerhub to report the error. Anyway, this should work in 4.12.x just use it for the time being.