Mangrove Roots are not opaque with Fast graphics, creating a lot of lag.

Minecraft typically runs at a smooth framerate for me, usually around 100fps. However, when I am in a mangrove swamp, it dramatically decreases, and my GPU is supposedly at 100% usage. I believe this is due to the mangrove roots being very complex, and abundant blocks. Fast graphics do not reduce their detail and leave them transparent.