When surpassing chunk boundaries with leaves in sight, you will experience a FPS drop proportional to how many leaves are in sight and how low the render distance is. This is a problem when exploring any biome containing trees while having a low render distance, or exploring jungles without low render distance. It is worse when exploring a jungle with low render distance, but this issue is also not restricted to naturally generated leaves. The resulting FPS drop could be reduced or stopped by pressing F3+A to reload chunks. Turning off biome blend does not affect this issue.