Minecraft Bedrock has only two seasons: winter and summer. In addition, the transition between them occurs abruptly. The author of the Autumn Birch texture pack didn’t like it and he decided to change it!
After installing these textures, the appearance of the foliage of birches and seedlings will depend on the location. For example, closer to the winter biome, the leaves will turn orange and yellow, and towards the summer – green. It seems like a small detail, but this makes the game better and cooler!