Adaptive Terrain is a specialized Blender tool for generating realistic and detailed terrain while optimizing resolution and reducing memory consumption. Its intelligent algorithms create natural-looking landscapes with minimal data, and use camera culling features to increase terrain resolution in areas closer to the camera for faster render times and smoother viewport performance. With Adaptive Terrain, you can:
• Optimize terrain resolution with camera culling features
• Increase resolution in areas closer to the camera for high-quality rendering and smooth viewport performance
• Generate natural-looking landscapes with ease
• Minimize memory usage
• Create realistic and detailed terrain
• Work with simple hills to complex mountain ranges
• Use intuitive interface and powerful algorithms

What it has;

ADAPTIVE RESOLUTION

The generator automatically adjusts the resolution of the terrain based on the distance from the camera, ensuring that it looks its best without wasting resources on rendering distant details.

CAMERA CULLING

The generator only renders the terrain that is visible to the camera, further improving performance.

TILEABLE TERRAIN

 It let you to tile the terrain by creating a grid of instances without using too much memory. This is a nice way of filling the background of your scenes

DISPLACEMENT

With the dynamic tessellation, you will always have a high resolution mesh near to the camera and this is the perfect solution if you are trying to add material displacements to a large scale  mesh and get realistic close up renders.

TREES

You can even scatter a collection of trees on the surface of the terrain and use a mask to remove it from where you don't want them to be. As they are just instances, they also don't use too much memory.

It`s not limited to trees. you can create a vegetation collection, buildings...

You can optimize how it's shown on the viewport so it don't get to heavy to work on your scene, while keeping all of the quality and heavy work for the render time.

Everything is customizable, so you will have full control over the quality and optimization, reducing mesh resolution on the viewport, switching the trees to bounding boxes.

Do you want to just create optimized high resolution grounds and walls? The INFINITE DISPLACEMENT tool is perfect for this;

https://blendermarket.com/products/infinite-displacement

Read the Documentation, if you want more information on how to use it.