Tree

A tree was a woody form of plant that grew on several planets. Generally forests were composed (at least partly) of trees.

According to the Rani, a tree had four times the life expectancy of a human being. (TV: The Mark of the Rani)

The forests of Eden were dense even in the small section captured by Tryst's Continuous Event Transmuter. (TV: Nightmare of Eden)

Vislor Turlough once described the trees on Trion as being three times the size of Earth trees, with plate-like thick mauve and purple leaves growing in spirals up blood-red trunks. (AUDIO: Loups-Garoux)

Calderon Beta was home to a four hundred foot tall tree "growing out of a clifftop on the north side of a mountain in the middle of the sea". (HOMEVID: First Night)

A species of tree existed on Gallifrey with silver leaves. These reflected the morning sunlight, making it look like the forests were on fire. (TV: "A Desperate Venture", Gridlock) There were also green forests, similar to those on Earth.

Intelligent or sentient trees
Whilst on Earth in the 1820s, the Rani mined a section of forest with mines that turned humans into trees. Following their transformation the former-humans retained some level of consciousness. (TV: The Mark of the Rani)

In the year 5345, the Eleventh Doctor encountered a group of Androzani trees who were attempting to flee their doomed homeworld. (TV: The Doctor, the Widow and the Wardrobe)

By 5,000,000,000 many trees that had originated on Earth had achieved sentience and humanoid form. (TV: The End of the World)

The Sixth Doctor and Frobisher encountered a talking tree while in Astrolabus' realm. (COMIC: Once Upon a Time Lord)

Types of tree
Various types of tree, both sapient and ordinary, were known to exist, including: allowcachedresults=true category=trees from the real world namespace=0 columns=6 inlinetext=yes replaceintitle=/\(.*\)/ allowcachedresults=true category=trees namespace=0 columns=6 inlinetext=yes replaceintitle=/\(.*\)/