According to Guinness World Records, the 82-meter-tall tree in Bucharest, decorated with 2.8 million colorful bulbs is the biggest one in the world. It is 76 metres high and made of steel.

From the show, there is this tallest xmas tree :)

The worlds tallest Christmas tree towers 46 meters (147ft) over shoppers at the annual Christmas bazaar December 18, 2001 in Dortmund, Germany. The giant tree took six weeks to build and consists of over 1,700 small Christmas trees and weighs 100 tons.

All info are from internet, so i dont know which one is the current tallest one.. Should be the first one, but it is made of steel.. Hmm..

圣诞树是这是世界上最美好的东西。