I have always thought banyan tree and bodhi tree are the same; just different terminology arising from language, culture, history and country, and that Buddha sat under the tree (not sure which one now) for seven days after enlightenment.
Whatever the case, we were given the opportunity to walk past a thousand-year old banyan tree in our recent trip to Guilin and it had grown so enormous; the city management had to install poles to support the heavy, outstretched branches!
Fact time - the tree is about 18.6 meters tall with a trunk diameter of 1.62 meters (around my height) and a crown diameter if 32 meters! It was first mentioned in 1104 and listed as one of Guiln's sixteenth scenic places back in the Qing Dynasty under "榕城古荫".
p.s. i didn't feel exceptionally enlightened under the shade although it was a leisure stay given the cool weather.
Do check out the posting for the summarised itinerary of Chan Brother's tour package (guaranteed no shopping stops) to Guilin; it would give you a better overview of my trip. :)