The Italian artist Giuliano Mauri was known for creating "natural architecture" by blending organic materials such as branches into large-scale outdoor works of environmental art that were, because of the nature of the pieces he worked with, temporary. Building on his love of wood and nature, Mauri conceived of forming outdoor living cathedrals with trees grown in such a way as to form the walls and roof.

Mauri's first attempt to create a living cathedral in 2001 laid the groundwork for the new "Tree Cathedral"—or "Cattedrale Vegetale"—installed near the northern Italian city of Trento in late 2010. With the artist's death in 2009, it serves as a memorial to his work and life.

The Tree Cathedral consists of 42 columns forming a basilica of five aisles. Fir poles and branches from hazels and chestnuts have been woven together to create a supporting structure for the 42 beeches planted to eventually grow and form the columns. As planned, the surrounding support structure will deteriorate as the beeches grow, creating a seamless transition from the manmade to the natural.

Standing at the foot of Mount Arera, the Tree Cathedral's structure includes 1,800 fir poles, 600 chestnut branches, and 6,000 meters of hazel branches joined together with wood, nails, and string. The Cathedral takes up 650 square meters and took months to construct. It is more than 90 feet long, nearly 80 feet wide, and ranges in height from about 16 feet to nearly 70 feet.

Update March 2019: Unfortunately, after some thunderstorms and rains in November 2018 in North Italy, the cathedral is now heavily damaged. It is not known if and when the cathedral will be repaired.

Update December 2019: the Cathedral is being officially demolished forever.