Banyan trees (Ficus spp.) are known for their ability to spread over a vast area through their unique growth habit. Here are some key details about how banyan trees can cover multiple acres:

1. Aerial Prop Roots: Banyan trees start off as a single tree, but then develop aerial prop roots from their branches. These aerial roots grow downwards and eventually reach the soil, taking root and developing into thick, secondary trunks.
2. Vegetative Reproduction: The new trunks formed from the prop roots are physically connected to the parent tree, allowing the banyan to spread outwards vegetatively. This process continues as the new trunks send out their own branches and prop roots.
3. Vast Canopy: Over time, a single banyan tree can develop into a vast, sprawling canopy supported by multiple trunks originating from the prop roots. The canopy continues to expand radially as new prop roots take hold.
4. Giant Specimens: Some of the largest and oldest banyan trees have canopies that cover several acres. The Great Banyan Tree in the Acharya Jagadish Chandra Bose Indian Botanic Garden in West Bengal, India, is considered one of the largest, with a circumference of over 1,000 feet (305 meters) and covering an area of approximately 3.5 acres (1.4 hectares).
5. Interconnected Colony: While the entire banyan tree may appear as a single organism from above, it is essentially a clonal colony of trunks interconnected through the parent tree’s root system and the prop roots.

The ability of banyan trees to continually produce new trunks and expand their canopy allows them to maintain a vast, interconnected structure that can cover multiple acres, making them one of the few trees capable of such extensive horizontal growth.