backgrounds Bark Tree birch birch tree natural pattern nature outdoors birch forest forest haunted forest protective area recreation area spring spring forest tree wood woodland biome branch Canoe birch plant swamp birch trunk twig woody plant birch-tree bush germany Harz high landscape mountain precipice rock stone summer abstract bark betula pendula bumps dashes deciduous gray grey raised short stripes silver birch silver birch tree smooth texture textured tree trunk uneven Betula verrucosa white winter Botanical Garden dark japan japanese birch magnolia psychedelic starry starry night stars autumn blue sky clouds fall grass green leafa natural November plantation sunbeams sunburst woods yellow young