Largest canopy on a living tree
Thimmamma Marrimanu, Indian banyan, Ficus benghalensis
India (Anantapur)

Throughout the tropical world, many species of fig (Ficus) behave as banyans. Banyans spread by sending down cord-like appendages from horizontal branches that root when they touch the ground and become trunks. The trunks are quite strong and can support a portion of the canopy. Old trees can have hundreds or even thousands of these support trunks and their combined crowns can cover a hectare or more. The species that by far covers the greatest area is the Indian banyan (Ficus benghalensis), the national tree of India and often associated with shrines. Currently, India has six banyans that occupy one hectare or more. The largest is Thimmamma Marrimanu, located in Anantapur, Andhra Pradesh. Legend has it that a woman named Thimmamma threw herself on the funeral pyre of her dead husband in 1434 and one of the pyre poles spouted to become a young tree. Thimmamma Marrimanu’s combined crowns merge to occupy 2.19 hectares (5.41 acres), an area equivalent to three soccer fields. The roughly elliptical canopy spans approximately 190 m long by 145 m wide (623 x 476 ft) and is supported by nearly 4,000 prop roots.

Arguably the most famous banyan tree, albeit slightly smaller than Thimmamma Marrimanu, is The Great Banyan, located in the Indian Botanical Garden of Kolkata, West Bengal, with >3,000 supporting trunks. The combined crowns occupy 1.65 hectares (4 acres), forming a roughly circular canopy 145 m (476 ft) in diameter. While not nearly as old as some of the other giant banyans, this one is at least 250 years old, and retained its original stem until 1925. The tallest portion of the entire plant is only 24.5 m (80 ft).

It's worth noting that there are even larger clonal trees, such as quaking aspen (Populus tremuloides), which are technically a single organism, but the canopy cannot be compared with banyan trees as it is more like a forest with lots of gaps between the trees. The largest known individual clone, named Pando, grows in the Wasatch Mountains of Utah, USA, and has a single root system that covers 43.6 hectares (107.7 acres) and contains 47,000 individual stems. With an estimated total weight of 6,000 tonnes (6,614 US tons), it is deemed the world’s heaviest organism. Age is debated, but some dendrologists put it at 14,000 years or more, which would also make it the world’s oldest living organism.