Assign a Random Points operator on the mountain

Select the node plane and create a Random Points Allow to display points randomly over a geometry Read More modifier ( Modifiers>Operator->Random Points ) and set it like that:

Assign a Sprite Points renderer on the mountain’s geometry

Create a Sprite Points Display point using any kind of 2D Layer as map Read More renderer ( Renderers>Points>Sprite Points )and set it up like showed below.

Import the sprite texture

Now you can drag and drop the Sprites_SummerTree.png from Standard Pack>Texture>Objects inside of the Sprite Points renderer and delete Dot White a.png .
Enable the depth Sorted parameter on the sprite point renderer.
You should have something like this:

Assign a Point Scale attribute on the mountain vertex to modify it's sprites

• I now add a Point Scale Scale all vertices of geometry Read More modifier on the 3D Layer Plane ( Modifiers>Attribute>Scale ).
• This attribute will apply on the vertex only so on the generated particles on the plane (in this case, the trees), not shape of the plane. I set it to 0,0,0.
• Drag and drop the Smode_Heightmap.png over the Point Scale Scale all vertices of geometry Read More modifier and set it up like showed below (in advanced parameters mode again)

Now the Point Scale Scale all vertices of geometry Read More modifier is set up to mask every sprite on the heights of the mountain, according to the black and white values of the displacement map, you can trick it as you want.
If you want to go further in the customisation of the map, select the shared Smode_Heightmap.png and turn it into a composition (Ctrl+Shift+C) (don’t forget to put the compo into 16 bits) and add layers or change them.