bark botanical crack crevice forest formation grain lumber madera natural nature plant texture textures tree wood wood grain backdrop background barnacles beach carved cave coast coastal contour face rock sandstone weathered bricks building colors colours cracks deterioration firm paving poor quality rough solid strength surface wall walls cracked dead desert drought dry earth global warming ground grunge heat pattern sand stones summer warming arid baked bare Mud parched sere Soil water shortage Cornish cornwall England english geology Great Britain lines pink purple sedimentary worn yellow coastline Daymer Bay gray grey striped