It was one of those beautiful days when everything is wet. Between wind, rain and fog, moisture creeped in every crevice from all directions. Water being that which merits the most gratitude, I see wet days as beauty, though they break limbs and topple trees. Mist feeds things like mistletoe and lichen. Water is a rare delicacy they savor, and when they get a drink on a new year's first day, it is cause for celebration.
Against wet bark, lichen glows brighter than normal. Flat, winter light and exaggerated contrast bring pale lichens to prominence, but it may not just be wet bark at work. Lichen may actually glow brighter in wet, winter weather.
Lichen is a symbiotic pairing of algae and fungus, the original pioneers of dry land. Long before there were trees, flowers or fields of grass, algae and mold grew on a stark landscape of rock, sand, dirt, but nothing that could be fairly called "soil." Soil is an end result of biodiversity, not its ancestor. Algae, moss, molds and mycelia don't need soil; soil is the graveyard of their proliferation and evolution.
Lichen likely predates most or all terrestrial plant and animal life, and a warm, wet winter afternoon may remind it of the stark, ancestral Earth where algae and mold first partnered. It may glow mint-green and grateful against gray bark.