Oak Trees
Considered by many to be a magical tree. Devotees of the Phoenician God Baal made sacrificial offerings under the Oak. Socretes regarded the Oak as an Oracle tree. All Druid rites involved the use of an Oak tree. The Oak was also sacred to the Roman God Jupiter. In Scandinavia the Oak tree was dedicated to Thor.

Olive Trees
Very sacred to Greek Goddess Athena. Athena gave the Olive Tree the power to bear fruit. When Xerxes captured Acropolis he burned a mystical olive tree which reappeared by magic. A Dove also brought Noah a sprig of Olive tree to indicate it was safe to come out of the ark.

Laurel Trees
It was the Greek nymph Daphne that was being chased by Apollo who asked to be changed into another form. So Athena helped by transforming her into a Laurel tree. As such the Laurel tree became sacred to Apollo. The Laurel was said to give visionary powers and as such the Delphic Oracle used to chew the Laurel leaves to induce visionary powers. The Laurel was also hung on doorways to keep ghosts away. 

Hazel
Has been used by magicians for centuries to make their magic wands. In Roman mythology Apollo gave a Hazel rod to Mercury. During the middle ages Hazel rods were used against demons. Over the centuries forked hazel rods have been used for dowsing. 

Pine Tree
The Romans regarded the opened Pine cones as symbols of virginity. The cones were sacred to the Goddess Diana. In Roman mythology, Rhea turned Attis into a Pine tree. In Phrygia Pine trees were sacred to Cybele. The devotes of Dionysus wore foliage from Pine trees. The Pine served as a bridge for Shamans between the world and the supernatural dimension.

Elder Trees
In Scotland and Wales it was believed that the dwarf Elder on grew on ground which had been soaked in blood. Elder was not used in a Childs cradle as it was believed the would be harried by fairies. In Germany it was thought unlucky to brink an Elder branch into the house. Elder was also considered a protection against evil. During the horror times of the Catholic inquisition people carried Elder as a protection against the church. Elder was also believed to protect gardens. It was thought very unlucky to break or cut an Elder branch. Gardeners had to ask permission from the tree first. It was unlucky to burn Elder wood. This stems from the fact that the church often used Elder in burning people. 

Elm Trees
In England the Elm tree was associated with elves. It was also believed that the falling of leaves of the Elm out of season predicted disease among cattle. The Elm was also used to cure cattle by means of the "Need fire". Elm leaves have also been used for centuries for medicinal purposes. Herbalists still use Slippery Elm.

Soma
Was a sacred plant that was used to make a drink that was consumed in Vedic sacrificial rites in honor of the God Indra. Soma was believed to be the drink of the Gods. It was thought to bestow divinity upon mortals. Some people believe Soma was in fact the leafless plant, Sarcostemma Acidum.

Myrtle
An evergreen plant that is associated with love and marriage. Ancient Egyptians consecrated it to Hathor. In Ancient Greece it was sacred to Aphrodite. In ancient Rome brides wore wreaths of myrtle blossom on their wedding day.

Mistletoe
The Druid priests use to distribute Mistletoe to worshippers after a white bull had been sacrificed to the spirits. The Mistletoe was then taken home and hung from the ceiling to ward off evil forces. In ancient Rome it was used to protect against evil. The Romans also used it as a way to speak to ghosts. Modern day couples kiss underneath the mistletoe, a custom that goes back to the Celtic church. 

Holly
Has been used down through time as a protection against evil. It was also hung around houses as a protection against lightning. Its use at Christmas may be traced back to ancient Rome were it was used during the festival to Saturn. 

Amaranth
A flower which is a symbol of immortality. A crown made with this flower will bring fame and fortune to those who wear it. The Amaranth was also used to decorate images of Gods and tombs. The Amaranth was also sacred to the Goddess Artemis of Ephesus. The name Amaranth derives from Amarynthos, a hunter and King of Euboea. 

Broceliande
Was a magic forest in ancient Brittany that figured in Arthurian legend. It was the place that Merlin was enchanted by Viviana, Lady of the Lake. The name Broceliande is often symbolic of the dim unreality of legendary scenery. Paimpont forest, also known as Brocéliande, is in the French commune of Paimpont, near the city of Rennes in Brittany. As Brocéliande it had a reputation in the Medieval imagination as a place of magic and mystery. It is the setting of a number of adventures in Arthurian legend, notably Chrétien de Troyes's Yvain, the Knight of the Lion, and locals claim the tree in which the Lady of the Lake supposedly imprisoned Merlin can still be seen today. Other legendary places said to lie within the forest include the Val sans Retour, the tomb of Merlin, the Fountain of Youth, and Hotié de Vivianne (castle of the Lady of the Lake).

Baaras
Known to the Arabs as the golden plant. The plant grew on Mount Libanus. The Baaras flowers in the month of May after the snow melts. During daytime it is invisible, but at night it can be seen by torchlight. It was of great assistance to alchemists in the transmutation of metals. A marvelous plant known to the Arabs as the "Golden Plant," which is supposed to grow on Mount Libanus, under-neath the road that leads to Damascus.

Ash Tree
There are many superstitions surrounding the Ash Tree. The Christmas log was of Ash because it believed to bring fortune to the family. Tools made of Ash enabled a man to work harder. A carriage whose axles were made of Ash would go faster.

http://www.paralumun.com/sacredtree.htm