The mangrove trees have developed different exclusion and excretion strategies to limit the salt level in their tissues and withstand salinities ranging from 2.1 to 3.1oz per liter (60g to 90g/l). Some, like the stilt mangrove trees, filter salt at their roots and block 90% of it when absorbing seawater. Others, like the gray mangrove tree, let the salt pass through their roots but reject the excess through their leaves thanks to salt glands.