You've probably been to a birch forest in Minecraft before. Tall black-and-white trees, flowing grass, and, honestly, not much else. They're basically regular forests, but with less in them, and only one type of tree. Boring.
That's where this pack comes in. With the Autumn Birch resource pack, birch forests become fall-colored, with orange grass, red trees, and fallen leaves scattered around the ground. Explore the autumn!
OptiFine is required for one feature (the leaves on the ground), but you can use this pack just fine without it.
This pack (and almost every single other resource pack) should work for nearly any version of Minecraft. Even if it says it's incompatible in the menu, it'll work fine. It should work with all other resource packs, but keep in mind that the birch leaves and leaves on the forest floor are 16x.
The screenshots use Sidlur's Shader, everything else is by me.
Enjoy! 🎃