Ever a pioneer, the towering cypress found protection against
wind, one of its few natural enemies. Developing a conical base and
extensive root system in a poor foundation of swampy soil, the tree is
able to withstand high wind. Although the tallest in the forest, it is
seldom if ever blown down, even in a hurricane.
When the base of a cypress is covered with water for any
considerable time, it produces a conical "knee" which grows from the
roots to a point above the surface of the water. A knee frequently
reaches a height of 8 or 10 feet, corresponding in general to the average
high-water level of the locality.
The function of the cypress knee is a mystery. Like the parent
tree it has a root system, although it never sprouts or forms a new tree.
Experiments show that submerged roots will invariably send erect
branches to the surface, thus demonstrating that a tree will always
produce knees when the roots are under water. Hence it has been
suggested that the knee may be a breathing organ for the main roots,
although this is uncertain.
Cypress knees are almost always hollow except in very early
stages. They are of gnarled and twisted structure and extremely tough
but much lighter than the parent wood. Knees die when the tree is cut
but removing them does not seem to affect the tree.
The geographical range of cypress in the United States extends
from Delaware in Florida, westward along the Gulf of Mexico to