You might think that the erection of the maypole is a tradition associated exclusively with May Day (Beltane), but you would be wrong. The raising of the Midsummer tree is an authentic Midsummer custom found in many areas, including Wales, England, and Sweden.
The custom was called "raising the birch" in south Wales, and "the summer branch" in the north, and the dancing around it "the dance of the birch". It was decorated with ribbons, flowers and even pictures. A weathercock with gilded feathers surmounted it. The cry of the cock at sunrise indicates the end of the darkness and the start of the day. Celtic festivals were held from dusk till cock crow of the next morning.
Sometimes one village would try to steal another village's pole, and it was considered very ill fated and a disgrace to one in this fashion. The bereft village was not allowed to raise another until they had succeeded in stealing one from elsewhere, and the poles were guarded all night by groups of youths and men.
(From the book "Midsummer: Magical Celebrations Of The Summer Solstic" by Anna Franklin).