Snowy taiga trees almost always generate with line or "grate" shaped patches caused by certain quarter chunks failing to generate trees in them. To reproduce, use the seed -2958033715087727745 and teleport to -2134 127 515 then look down.
MC-133728
Trees generate in 8 block wide lines or spots in snowy taiga
Resolved
Fixed
1
(Unassigned)
Unconfirmed
biome, chunk, quarter-chunk, world-generation
Minecraft 1.13-pre9
Minecraft 1.13-pre10
Retrieved
This looks like it was fixed in 1.13-pre10 (probably along with MC-125007) because I cannot reproduce it anymore. That was fast.