The magnificent and ancient sessile oak known as the Birnam Oak stands close to the south bank of the River Tay, a short walk from the centre of the village of Birnam. Park in the centre of the village and follow brown tourist signs on foot that lead you along "Oak Road" and around a playing field en route to a path that runs parallel to the bank of the river.
There are a number of imposing trees here, and visitors have obviously confused some of them for the Birnam Oak in the past. The result is some nicely humorous signs. One stands in front of the first very large tree along the path and declares "It's not me, I'm a sycamore..."
The next possible candidate has a sign "Not me either, keep going..." When you do reach the Birnam Oak, there is no mistaking it. This huge tree has an enormous spread, and several of the lower branches are propped up with wooden supports. (Continues below image...)
According the the nearby information board the oak has a circumference of 24ft and the bottom 10ft of the trunk is hollow. At some time a fire has been lit in the interior, but the tree continues to thrive regardless. No one knows how old the Birnam Oak actually is, but it is believed to be the only survivor of the "Birnam Wood" which featured in Shakespeare's Macbeth. In the play the witches said "Macbeth shall never vanquish'd be until Great Birnam Wood to high Dunsinane Hill shall come against him." The prediction came to pass in the play when Malcolm III's forces attacked Macbeth at Dunsinane Hill using branches from the wood to camouflage themselves.
It takes a stretch of the imagination to suppose that the Birnam Oak stood here in the 1050s, and we have to remember Shakespeare was a dramatist and not a historian. It is possible, however, that the plot of Macbeth was inspired by a visit Shakespeare is said to have made to Perthshire as an actor in 1589. If so, then the oak was almost certainly well grown when he visited.
While visiting the Birnam Oak, don't overlook an important near neighbour, a short distance to the west. This is the Birnam Sycamore, a "mere" 300 years old, but even larger than the oak. The information board nearby tells us that it is 25ft in circumference.