Thanks for your suggestion. Indeed, lowering the taller trees would make the mountains and river more dominant, but from a first person ground level perspective, those tall trees really add height contrast and majesty to the landscape. Besides, in real life, aspens and birches do grow to impressive heights.

That's strange, the spawn is on the banks of the river. Are you sure you loaded the map correctly and are using Minecraft 1.14.4 or above?

Thank you very much!