moss on trees

[dondons]

while driving throught the Fort William area of Scotland last week (February) I noticed that the deciduous tress were covered in a hairy moss that in some places looked like lace. It was a silvery grey green - any ideas as to what it is- does it kill the trees - is it because it is damp? why haven't I seen it in other places?

[logman]

Its not exactly moss but something closely related known as lichen (normaly pronounced lykhen) Your right it does like the damp atmosphere and its also a good indicator of clean, unpolluted air.

it will not harm or kill the trees as it does not penatrate through the bark. It can be found growing on rocks and stones also..

[espookid]

it is also supposed to be on the ( I think ) north side as well and is used by orienteers to help when they cannot see the sun