The so called “briccole”, the posts in chestnut oak on which Venice is built, are used for docking gondolas and as beacons. They are at least ten meters (32.8 feet) high and once driven into the lagoon, they have an average life not longer than 5-10 years. Their section affected by tide rise and fall becomes the natural home for microorganisms as well as sea flora and fauna, but once corroded, they are completely replaced.
Many more ideas in their unfortunately usability-lacking site. (via cielbleu)

