The idea of the link between Father Christmas, linked with the Yuletide or Winter Solstice, and the Green Man of art and architecture has been explored since at least the time of Lady Raglan in 1939. Father Christmas is traditionally depicted with crowns or other ornaments of holly, ivy and mistletoe and often dressed in green robes.
The Green Knight of medieval literature -- often equated with the artistic Green Man -- had a Winter Solstice connection. He scheduled his rematch with Sir Gawain on the shortest day of the year. Interestingly, in the first contest between the two, the Green Knight's head was cut off by Gawain but with surprising results. The headless body of the Green Knight retrieved the head, which offered the winter challenge to Gawain before body and head went on their way together.
The head cult perspective offers an obvious link with the foliate head of the Green Man depicted in art.
Victorian drawing of Father Christmas from a copy of Charles Dickens: A Christmas Carol with green robe and foliate crown.
If we go back to the Tantric connections suggested for the Green Man here, we can find in the Kabbalah the idea of a father figure known as Abba, which means "father" in Hebrew. This Abba is related to the male principle of creation. He is paired with Imma, meaning "mother" in Hebrew, the female principle.
While Judaism disdained anthropomorphic icons, Abba and Imma were described in the texts as mated in divine union resulting in the generation of progeny or creation. Abba can be equated with Adam Kadmon, the primordial man. The divine union of Abba and Imma is similar in many respects to that of the Tibetan concept of Yabyum. Yab also means "father" in Tibetan, while Yum means "mother." The Yabyum depiction of deities in Tibetan art shows a male and female deity in sexual union. The literary references to Abba and Imma are also quite sexually explicit in their description of the cosmic union.
Despite the taboo against iconography, Abba was still meditated upon in the sense of his Partzufim or "face." The Kabbalistic practitioner concentrated on the divine face of Abba and other forms of the creative male principle, particularly focusing on the massive beard. According to some interpretations, by concentrating on the face of Abba and traveling along the hairs of his beard, one achieves unity with the Divine Image. The similarity with Tantric visualization of the deity is striking.
Also, the aspect of meditating on the face brings us back to the head cult, i.e., in the Green Knight example, and to the "face motif" discussed here earlier in connection with the Green Man.
Non-religious depiction of the head of Adam Kadmon, who himself is seen as a form of the Tree of Life.
Although I have not found a direct solstice link with Abba and Imma, the erotic union of the two, or rather the union of their "faces," is considered to have generated the ten Sephirot of the Sefer Yetzirah "tree."
Abba, along with other forms of the male principle, are also directly seen as types of the Sun, while Imma and the female principle including the Shekinah were seen as types of the Moon. The Partzufim or faces motif blends quite well with this linkage to the celestial luminaries.
Like Abba, Father Christmas has a full beard while the Green Man has vegetation spewing from his mouth. In all these cases, the representation may be that of the generative powers of the Sun.
Paul Kekai Manansala