changing logs

[OkottaShinigurai]

I'm using Pangamma's PixelStacker v1.14.2a to create schematics for schematica and recently found out that schematica changes all logs to oak. I'm using schematica 1.8.0.169 and I'm playing in minecraft version 1.12.2

[OkottaShinigurai]

I'm trying to make a pixel art from this picture:

and as you can see from this small area of the pixel art it has multiple log types:

but when I save it as a schematic and open it in minecraft it looks like this:

ps: I also just noticed more changes in blocks