Forests - what are the patterns of a forest (e.g. same tree types in bunches, or random tree types)?

[Wannabelifeguard]

Hi guys,

The question is primarily about the Boreal forest - the forests found throughout Europe/Russia/North America.

I am trying to make a 3D map of a made up forest and at the moment I have just been randomly putting poplar/birch/fir/pine trees everywhere. But that made me wonder, is that really accurate? Perhaps the pine trees should be clustered in one area and the fir trees in another area? Or maybe pine trees are always surrounded by birch trees? Who knows, any help would be appreciated.

Also, do you know if the physical terrain should have a lot of changes in height or is it mostly flat? Would you expect to find swamps in the boreal forest? If so, what trees would be nearby?

Would the land slope or would it be rolling like the steppe?