[slow music]
No other trees have an anatomy quite like a Cypress tree.
In some aspects, they're not very different from other plants.
But one component of the Cypress' anatomy defied a definitive explanation for much of recorded history.
Perhaps that's because the explanation is found in the time before recorded history.
[slow music]
In much of the Southeastern United States, the Baldcypress is one of the most prominent and recognizable native plants.
This recognition can undoubtedly be ascribed to the Cypress' unique and oftentimes secretive anatomy.
Its trunk is creased, its branches, skeletal, but its most mystifying attribute is seemingly disconnected from the tree altogether.
Cypress "knees", as they're called, are isolated components of the tree only linked to the main body underground by the roots.
Their presence is obvious, but their function long remained concealed.
But the anatomy of any organism, plant or animal, is often driven by the environmental forces that dictate its evolution.
For the Cypress tree, an understanding of the tree's past, its history and evolution, may provide strength to one possible explanation of this
otherwise unexplained anatomy.
Though the Cypress is now virtually synonymous with the country's southern states, the remains of prehistoric Cypress trees have been found in many
regions that today are devoid of them, including as far north as North Dakota.
These prehistoric Cypress trees, living and dying over 60 million years ago, now exist only as petrified wood, the very fibers of their body
made up entirely by rock and mineral.
But the fact that these ancient Cypress trees have been preserved as petrified wood provides a critical insight into why these trees once existed there,
and how this past shaped the Cypress' current anatomy.
In order for a tree like a Cypress to become petrified, the organic components of its body must be replaced with the mineral quartz.
Not every plant that dies undergoes this process.
In wetlands habitat, where dense foliage makes its home atop slow-moving water, a buildup of organic material deprives the water of oxygen
and makes it uninhabitable for decomposers.
When a plant dies in a wetlands habitat, therefore, its body is often left untouched, and over time, absorbs enough quartz-carrying water to undergo
the process of petrification.
This means that at the time these prehistoric Cypress trees lived, many regions of the country weren't at all what they are today, but rather,
representative of an old wetlands ecosystem.
Such a fossil record indicates that for over 60 million years, the Cypress tree has lived in a similar wetland environment as that which it occupies today.
Presently the Baldcypress is a wetland obligate, meaning that it exists almost always in wetlands
When any organism has such a long evolutionary relationship, coupled with a nearly exclusive dependency on a particular type of habitat,
its anatomy is likely to reflect specialized adaptations developed in response.
This makes the most likely explanation for the Cypress knees being some kind of function uniquely specialized to wetlands environments.
For a tree as large as a Cypress, the characteristic instability of wetland soil is a particularly difficult condition for survival,
and the knees of the Cypress may represent an adaptation that helps the tree remain upright.
Cypress trees possess both deep tap roots and widespread lateral roots, which, along with the above-ground knees, may enable the Cypress to withstand
both the everyday challenges of wet soil, and the seasonal impacts of storms and hurricanes.
Thanks to its knees, a Cypress tree is able to continue to live in a habitat in which survival would otherwise be impossible for such large trees.
The secretive nature of the knees made their purpose the subject of years of conjecture, but the role they play in the life of a Cypress tree
is proven apparent in the long relationship that the species maintains with its environment. The evidence of such a relationship has survived
not only the weathering of this dynamic landscape, but the test of time as well.
[slow music]
[slow music fades out]