Mangroves were added to the Overworld in Minecraft 1.19, The Wild Update. Mojang Studios also partnered with The Nature Conservancy to raise over 227,000 USD and awareness for real world mangrove tree restoration. Check out the Rooted Together map with Grian, Wild, Authentic Games and Stacyplays, and the work done in Kenya by the Mtangawanda Women’s Association.
You can read more about this project here: https://minecraft.net/article/the-mangrove-restoration-project