Sharp-eyed residents of San Francisco may notice something unusual about their city's emergency services: The ladders on all of the fire trucks are made of wood, not metal. Why? In a city with low-hanging power lines, non-electricity-conducting wood is a safer choice than metal.
This awesome video by Ask Media Productions takes a look inside the the SFFD's ladder shop, where they repair and build ladders up to fifty feet in length out of Douglas Fir. The resultant ladders can weigh up to 350 pounds (which actually makes them more stable in a crosswind) and are built to last for more than a lifetime: The oldest ladder the SFFD has in service is from 1918, making the 92-year-old object older than anyone in the department. And to say they are carefully constructed is an understatement, as the raw wood must spend fifteen years in the shop, acclimating to the local humidity, before they are deemed worthy raw material.