Other trees—the yew, the cypress, the alder, and the ash, were venerated, to judge by what Lucan relates of the sacred grove at Marseilles. The Irish Druids attributed special virtues to the hazel, rowan, and yew, the wood of which was used in magical ceremonies described in Irish texts.619 Fires of rowan were lit by the Druids of rival armies, and incantations said over them in order to discomfit the opposing host,620 and the wood of all these trees is still believed to be efficacious against fairies and witches.
The Irish bile was a sacred tree, of great age, growing over a holy well or fort. Five of them are described in the Dindsenchas, and one was an oak, which not only yielded acorns, but nuts and apples.621 The mythic trees of Elysium had the same varied fruitage, and the reason in both cases is perhaps the fact that when the cultivated apple took the place of acorns and nuts as a food staple, words signifying "nut" or "acorn" were transferred to the apple. A myth of trees on which all these fruits grew might then easily arise. Another Irish bile was a yew described in a poem as "a firm strong god," while such phrases in this poem as "word-pure man," "judgment of origin," "spell of knowledge," may have some reference to the custom of writing divinations in ogham on rods of yew. The other bile were ash-trees, and from one of them the Fir Bile, "men of the tree," were named—perhaps a totem-clan.622 The lives of kings and chiefs appear to have been connected with these trees, probably as representatives of the spirit of vegetation embodied in the tree, and under their shadow they were inaugurated. But as a substitute for the king was slain, so doubtless these pre-eminent sacred trees were too sacred, too much charged with supernatural force, to be cut down and burned, and the yearly ritual would be performed with another tree. But in time of feud one tribe gloried in destroying the bile of another; and even in the tenth century, when the bile maighe Adair was destroyed by Maelocohlen the act was regarded with horror. "But, O reader, this deed did not pass unpunished."623 Of another bile, that of Borrisokane, it was said that any house in which a fragment of it was burned would itself be destroyed by fire.624
Tribal and personal names point to belief in descent from tree gods or spirits and perhaps to totemism. The Eburones were the yew-tree tribe (eburos); the Bituriges perhaps had the mistletoe for their symbol, and their surname Vivisci implies that they were called "Mistletoe men."625 If bile (tree) is connected with the name Bile, that of the ancestor of the Milesians, this may point to some myth of descent from a sacred tree, as in the case of the Fir Bile, or "men of the tree."626 Other names like Guidgen (Viduo-genos, "son of the tree"), Dergen (Dervo-genos, "son of the oak"), Guerngen (Verno-genos, "son of the alder"), imply filiation to a tree. Though these names became conventional, they express what had once been a living belief. Names borrowed directly from trees are also found—-Eburos or Ebur, "yew," Derua or Deruacus, "oak," etc.
The veneration of trees growing beside burial mounds or megalithic monuments was probably a pre-Celtic cult continued by the Celts. The tree embodied the ghost of the person buried under it, but such a ghost could then hardly be differentiated from a tree spirit or divinity. Even now in Celtic districts extreme veneration exists for trees growing in cemeteries and in other places. It is dangerous to cut them down or to pluck a leaf or branch from them, while in Breton churchyards the yew is thought to spread a root to the mouth of each corpse.627 The story of the grave of Cyperissa, daughter of a Celtic king in the Danube region, from which first sprang the "mournful cypress,"628 is connected with universal legends of trees growing from the graves of lovers until their branches intertwine. These embody the belief that the spirit of the dead is in the tree, which was thus in all likelihood the object of a cult. Instances of these legends occur in Celtic story. Yew-stakes driven through the bodies of Naisi and Deirdre to keep them apart, became yew-trees the tops of which embraced over Armagh Cathedral. A yew sprang from the grave of Bailé Mac Buain, and an apple-tree from that of his lover Aillinn, and the top of each had the form of their heads.629 The identification of tree and ghost is here complete.
The elder, rowan, and thorn are still planted round houses to keep off witches, or sprigs of rowan are placed over doorways—a survival from the time when they were believed to be tenanted by a beneficent spirit hostile to evil influences. In Ireland and the Isle of Man the thorn is thought to be the resort of fairies, and they, like the woodland fairies or "wood men" are probably representatives of the older tree spirits and gods of groves and forests.630
Tree-worship was rooted in the oldest nature worship, and the Church had the utmost difficulty in suppressing it. Councils fulminated against the cult of trees, against offerings to them or the placing of lights before them and before wells or stones, and against the belief that certain trees were too sacred to be cut down or burned. Heavy fines were levied against those who practised these rites, yet still they continued.631 Amator, Bishop of Auxerre, tried to stop the worship of a large pear-tree standing in the centre of the town and on which the semi-Christian inhabitants hung animals' heads with much ribaldry. At last S. Germanus destroyed it, but at the risk of his life. S. Martin of Tours was allowed to destroy a temple, but the people would not permit him to attack a much venerated pine-tree which stood beside it—an excellent example of the way in which the more official paganism fell before Christianity, while the older religion of the soil, from which it sprang, could not be entirely eradicated.632 The Church often effected a compromise. Images of the gods affixed to trees were replaced by those of the Virgin, but with curious results. Legends arose telling how the faithful had been led to such trees and there discovered the image of the Madonna miraculously placed among the branches.633 These are analogous to the legends of the discovery of images of the Virgin in the earth, such images being really those of the Matres.
Representations of sacred trees are occasionally met with on coins, altars, and ex votos.634 If the interpretation be correct which sees a representation of part of the Cúchulainn legend on the Paris and Trèves altars, the trees figured there would not necessarily be sacred. But otherwise they may depict sacred trees.
We now turn to Pliny's account of the mistletoe rite. The Druids held nothing more sacred than this plant and the tree on which it grew, probably an oak. Of it groves were formed, while branches of the oak were used in all religious rites. Everything growing on the oak had been sent from heaven, and the presence of the mistletoe showed that God had selected the tree for especial favour. Rare as it was, when found the mistletoe was the object of a careful