It is a ritual steeped in pagan mystery, updated for the coronavirus age.

Sick people in northern France occasionally leave garments in healing trees or "arbres a loques" in the hope of a cure, following a tradition that persists since pre-Roman times.

But locals who pay attention have noticed a recent change.

"The new development in 2020 is COVID masks," said Bertrand Bosio, who runs Nord Fantastique, a Facebook page devoted to the region's ancient sites and lore.

Tied to the branches of the healing tree in Hasnon, southeast of Lille, surgical masks can be clearly seen among items of clothing that range from socks to underwear – often left, Bosio said, by people suffering from fertility problems.

In another departure from ritual, the votive masks are hung "preventatively," Bosio believes – or perhaps hopes – rather than by COVID-19 sufferers who ought to be self-isolating.

Known as rag trees in Ireland, one of several other countries where the practice survives, the arbres a loques show pagan and Christian influences. Despite appearances, which can be disconcerting, they still bring people hope, he said.

"What's interesting about this place is that the ritual is still very much alive in our times," Bosio added.

"People turn to the healing tree when medicine has reached its limits and when science has let them down."

There is also a similar practice in Turkish culture.

Wishing trees, or "dilek ağacı" as they are known in Turkish, can be spotted anywhere in Turkey, with the one outside the House of Virgin Mary in Şirince in western Izmir province one of the most memorable. This tradition comes from the times of pre-Islamic Turkic tribes. As shamans, the people of this era prayed to their Tengri (God) through the temples they built near trees, the source of life. They were known to make wishes to their creator through these trees and with time after Turks accepted Islam, this practice evolved into wishing trees. Nowadays, people mostly write their wishes on paper and hang them on these trees or tie a bandana or piece of fabric on the branches as they make a wish.