Let the trees on your map spread over time similar to real vegetation
Mods introducing new content into the game.
Map generation and terrain modification.
As the title states, trees that spawn in Alien Biomes' cold biome (snow/ice tiles) will not spread and simply die over time.
lol, found the bug. tile_restrictions contain allowed tiles, not the forbidden ones. fixed in version 4.1.4 and 3.2.1
allowed
forbidden