Swamp Cypress Knees

Bald Cypress growing in swamps have a peculiarity of growth called cypress knees. These are woody projections sent above the ground or water that are part of the root system. Their function was once thought to be to provide oxygen to the roots, which grow in the low dissolved oxygen (DO) waters typical of a swamp (as in mangroves). However, there is little evidence for this; in fact, roots of swamp-dwelling specimens whose knees are removed do not decrease in oxygen content and the trees continue to thrive. Another more likely function is that of structural support and stabilization. Bald Cypress growing on flood-prone sites tend to form buttressed bases, but trees grown on drier sites may lack this feature. Buttressed bases and a strong, intertwined root system allows them to resist very strong winds; even hurricanes rarely overturn them.[9]