lines across bark
Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
No interactions present.
Seems very regular. The illustration in Encyclopedia of Life seems to be an irregular white patch with scribbly dark lines. Didn't notice those features when I enlarged the picture.
I would suggest it was just the pattern of the bark. Many birch species do tend to have horizontal lines like this.
I think what you are seeing might be the lenticels that appear on the surface of the bark in certain species of tree. They are particularly visible in Birch (Betula) and also Cherry (Prunus).
See my similar comment on the identical pic at http://ispot.org.uk/node/12598.
recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.
Lat/Lng: 51.2, -0.8
OS grid ref: SU8955