Seasonal variation in concentrations of carbohydrates and lipids in two epiphytic lichens with contrasting, snow-depth related distribution on subarctic birch trees
The lichens Parmelia olivacea and Parmeliopsis ambigua are common epiphytes in subarctic forests in Europe. They differ in abundance and vertical distribution particularly on birch trees, and these differences relate to the level and duration of the winter snow cover. Parmeliopsis ambigua is covered much of the cold season on the lower trunk whereas P. olivacea occurs well above the snow surface.