Trees are in the background and in the foreground of the Bible. From the beginning to end. They are a critical part of the action. The Tree of Life is mentioned early in the Genesis and also in the last chapter of Revelation, for example. There are over thirty kinds of them mentioned in the Bible. Some like the olive tree are mentioned quite often and are well know to us, both as to physical, literal manifestation and some of its symbolic meaning, ie. you know what the olive branch signifies. In some cases it is not certain what kind of tree it is that is being described.
Perhaps you didn't realize it but trees figure in the story of Abraham, in several places. For instance, after the call to leave Ur we are told in Genesis 12: 6 Abram traveled through the land as far as the site of the great tree of Moreh at Shechem. At that time the Canaanites were in the land. "Moreh" means teacher. It was a significant tree for Abraham and the Canaanites. Was some kind of school there? Was it an Oak? Some think it was.
As it turns out, a few days before my talk, the significance of trees for our contemporary culture was illustrated by the recent reaction to the poisoning of the Toomer Oaks of Auburn. There was quite an uproar. Auburn fans are justifiably feeling hurt and disappointment. (Rather than post a link, the reader can google to find various descriptions and pictures.)
Each tree brings its own blessing to us. Not only do trees provide food, medicine, shade, shelter, and other useful items for our lives but many useful images and metaphors to learn from. Hence the admonition for us to be a tree that bears good fruit. Or to be rooted. Or that if we'll be righteous we'll "grow like a Cedar of Lebanon" (Ps 92:12). There are of course many other Biblical examples of this.
Here are some of the links to interesting articles on this subject. Quotes from them are in italics.
The Spirituality of Trees
The tree is one of humankind's most powerful symbols. It is the embodiment of life in all its realms: the point of union between heaven, earth and water. In most mythology and ancient religious imagery, the tree was believed to have an abundance of divine creative energy.
Trees have long held a literal and symbolic fascination for humanity. Their source as a deep archetype of absorption begins with the earliest epic in the Western World, the story of Gilgamesh and his quest for the plant of life (a symbolic tree) that is snatched away by a serpent, thus illustrating that the use of the tree as a universal religious symbol is incredibly ancient; such utilization can be dated to at least the third millennium B.C.E. as a symbol of a rich cultural mythos, the major archetype being that of the center, the beginning where sacred powers first originated. The tree is the navel of the world, the "cosmic axis" (Axis mundi) standing at the universe's center where it passes through the middle and unites the three great cosmic domains: the underworld, earth, and sky (Roth, Stephanie. The Tree of Life, The Ecologist. Jan. 2000 v30il. TEL. ASAP. 18 Aug. 2003.).
My closing thought:
Amazingly, these ancient pagans got it right. Their mythologies are not literally true but thy intuited something of depth and validity. Even before it happened. The Cross is that Tree. And it cannot be escaped how that event changed the world and the course of history.