In the period encompassing Medieval art iconography began to be standardised and to relate more closely to the texts found in the Bible and became the basis for many of the images found in Meaning of Trees in Christian Art

Early Christian Art - Symbolism and Icons
The definition of the Christian Symbol or Icon in early religious Christian Art forms. A flower in Christian Art is used to represent abstract ideas or concepts - a picture that represents an idea and fundamental to understanding the icons and images found in Christian Art. A religious icon is an image or symbolic representation with sacred significance. The meanings, origins and ancient traditions surrounding Trees in Christian Art symbols date back to early times when the majority of ordinary people were not able to read or write and printing was unknown. Many Christian Art symbols or icons were 'borrowed' or drawn from early pre-Christian traditions.

Early Christian Art Symbols - The Meaning of Trees
Trees as Christian Symbols represents the following:

Acacia Trees - Acacia symbolizes the the Virgin's purity

Almond Trees - Almond symbolizes divine approval (Numbers 17:1-8)

Bulrush Plants - The bulrush symbolizes faithfulness and humility

Cedar of Lebanon Trees - The cedar symbolizes Christ

Chestnut Trees - Chestnut symbolizes chastity

Clover Plants - The clover, or shamrock, is a symbol of for the Trinity.

Cyclamen Plants - The Cyclamen symbolizes the Virgin Mary

Cypress Trees - The cypress symbolizes death

Elm Trees - The elm symbolizes dignity and faithfulness.

Fern Plants - The fern symbolizes humility

Fig - The fig symbolizes lust or fertility

Fir Trees - The Fir tree symbolizes patience.

Grapes - Grapes symbolize the blood of Christ

Holly Plants - Holly symbolizes Christ's crown of thorns and His Passion.

Hyssop Plants - Hyssop Symbolizes penitence, humility and baptism

Ivy - Ivy Symbolizes faithfulness and eternal life.

Laurel Trees - The laurel Symbolizes victory or triumph and can also symbolize eternity.

Lemon Trees - Symbolizes fidelity in love

Olive Trees - The olive symbolizes peace

Orange Trees - Orange blossoms symbolizes purity, chastity and generosity

Palm - Palms symbolizes victory.

Reed Plants - The reed symbolizes humiliation and is a symbol of Christ's Passion

Willow Trees - The willow symbolizes the Gospel