Great photo!

Thanks Johnny,

Dax

Very cool, thanks for sharing that picture.
Jeff

Neat knees. Nice to see the comparison. Thanks.

tj

Very interesting comparison and great photo Johnny!

Makes me wonder, do cypress knees have a physiological purpose such as root oxygenation in a water saturated environment?

Barbara

Very cool comparison. I will be patiently waiting for my blacypress trees to start forming knees - I just love the look of them. I will probably be waiting a while though - my tree is only 5 feet tall!

Hey Barbara,

I really don't want to give an answer to your question because I've heard knees give off gases, but a Google search suggests that 'some botanists believe this'.

Dax

I enjoyed noting the comparison on the "knees".I'm currently watching a knee growing several feet away from
a "perfectly"drained 'Peve minaret'.Other cultivars of T.d.
in this garden have not done so.A further comparison within the
genus would be the lack of Knees on Taxodium mucronatum ,a 40 year old specimen a few miles away.Doug

Here's what Wikipedia has to say about the "Tale of the Knees":

A cypress knee is a term used in the biology of trees to describe the distinctive structures forming above the roots of a cypress tree of any of various species of the subfamily Taxodioideae. Their function is unknown, but they are generally seen on trees grown in swamps. Some scientists have thought they may help in oxygenation to the tree's roots or assist in anchoring the tree in the soft, muddy soil.

Knees are woody projections sent above the normal water level, roughly vertically from the roots, with a near-right-angle bend taking them vertically upward through water so at least part of the protrusion will be exposed at low tide.[dubious ��" discuss] One early assumption of their function was that they provided oxygen to the roots that grow in the low dissolved oxygen (DO) waters typical of a swamp, acting as pneumatophores: mangroves have similar adaptations. There is little actual evidence for this assertion; in fact, swamp-dwelling specimens whose knees are removed continue to thrive, and laboratory tests demonstrate that the knees are not effective at depleting oxygen in a sealed chamber. Despite the fact that there is no expert consensus on their role, the supposition that they are pneumatophores is repeated without note in several introductory botany textbooks.

Another more likely function is that of structural buttressed support and stabilization. Lowland or swamp-grown cypresses found in flooded or flood-prone areas tend to be buttressed and "kneed," as opposed to cypresses grown on higher ground, which may grow with very little taper.

Trees that develop these "knees" include the following:

Glyptostrobus
Bald Cypress
Pond Cypress
Ahuehuete
Metasequoia

Thanks Alex...great info!

Barbara

I want to see Metasequoia knees!

Got a Peve minaret a couple years back should it be cut back?

The Texas Hill-Country Bald Cypress population do not develop kness. Used to think that that was because they were in a more upland environment with better drainage. But even when these trees are in swampy type conditions they do not develop knee formations. Have also seen analysis that shows these trees are different chemically from the standard eastern Bald Cypress population, thus this is probably a genetic difference or variation from the eastern population.
Believe the main benefit of the knees is as maple-grove states: it buttresses/stabilizes the trees in wet unstable ground.