I learned of cypress "knees," the vegetative structures of cypress trees, while on childhood visits to Florida with my dad and brother. They were amazing, mysterious swamp things. I later learned they were aeration devices for roots that are constantly in water.
Brad Rimbey went on a recent hike (2008) with Matt and Hope Corona who showed him (his picture) this cypress (Taxodium distichum named by Linnaeus) tree a few miles north of the Chassahowitzka Wildlife Refuge, western Florida, USA. He said "Thankfully this one and a few other granddaddies were too big to be logged out..."
Few can survive the numerous lightning strikes of the region.
Imagine the engineering feat required to move such masses to market. The maximum record is 45 m tall and 3.8 m in diameter.
As a boy I was skeptical of stories of pioneer woodsmen spending a night in a hollow tree or giant bears living in such trees. This giant tree eliminates that doubt.
The heart wood is resistant to decay and thus great for posts, patios, etc. It's highly prized as lumber for interior trim.