Trees on new buildings?

The hospital down the street is adding a new eight-story wing. When the steel frame appeared complete, it was capped with a US flag and a pine tree. Since then, I’ve noticed that every new building worthy of being called a “building” (roughly >= five stories) sports the Flag and Tree upon topping out. The flag I understand, in the mountaineer’s spirit of planting same at the summit. But a tree!? How/when did this get started?

Ever since we developed the notion of the concrete jungle, we have had to adapt our old habits to it.

How can a mountaineer plant a flag showing her conquest without a tree at the top of the steel mountain? Without the tree it is just a hunk of steel, but with the tree it becomes a mountain to be tamed.

Jeffery

The tree placed atop newly erected structures is a common and quite ancient custom, however I’m not familiar with this tradition’s origin.

It’s called “topping” and it signifies that the highest point of the building has been constructed. I believe the origin of the tree comes from the fact that early structures were made out of wood, so this was some sort of quasi-religious thing going on. Whatever the origin, it was revived in modern times as a publicity stunt to show off the construction of a new building.

David Feldman covers this in his book, Why Do Clocks Run Clockwise and Other Imponderables. Quoting selectively:
"The tree atop buildings (and bridges) under construction is known as the ‘topping out’ tree and celebrates the completion of the basic skeleton of the structure. In skyscrapers, an evergreen is attached to the top beam as it is hoisted, a signall that the building has reached its finalheight. For some builders, the evergreen symbolizes that none of the construction crew died in the effort. For others, the tree is a talisman for good luck and prosperity for the future occupants of the building.
“…the precursors of topping out are ancient…stem[ming] from ancient superstitions… The first evidence of trees being hoisted atop buildings was in AD 700 in Scandinavia, where they signaled that a completion party was about to begin. Black Forest Germans celebrated the nativity of Jesus Christ with the hoisting of Christmas trees. Today, topping-out trees are still most prevalent in northern Europe, particularly Germany and the Scandinavian countries. Indeed, Scandinavia’s greatest playright [sic], Henrik Ibsen, had his protagonist in The Master Builder meet his doom by falling while placing a topping-off wreath on one of his new buildings.”

He goes on in this vein, and concludes that in modern U.S., a flag is often used as a topping-off symbol.