Song of Trees

Once a month, each cleric or druid is required to perform the Song of Trees, a ritual that calls forth a dryad or treant, and then serve the creature by performing small tasks for a day. calling forth a dryad or treant and performing odd jobs for it for a day.
Mielikkian ceremonial garb consists of trousers, brown boots, a short cape (woven by dryads from spider silk and tinted with natural dyes), and a tabard that is long-sleeved in winter and sleeveless in summer. Capes cover armor (typically chain mail) in times of war. Colors vary with the seasons, each season having a base color and an accent. Winter is white with green accents, spring green with yellow accents, summer yellow with red accents, and fall red with white accents. The unicorn’s head of Mielikki, carved of ivory or bone or stitched in silver thread, is always worn over the heart.

https://forgottenrealms.fandom.com/wiki/Mielikki