Xanthoria sp ??

[JennyS]

The spread of Xanthoria parietina on trees, walls, roofs etc is due to increasing levels of nitrogen but the lichen isn't responsible for the death of the trees.

Your photo's aren't very clear so I can't suggest what the blue-grey stain might be but the last photo is of X. parietina.

[Lancashire Lad]

Hi SAHop, and welcome to WAB.

I'm an absolute beginner with regards to lichen, but I think that the blue green patch (third photo) may be something like Lepraria incana.

Many of the woodland trees in my area have very large patches, and it is also on many shaded rocky outcrops in local woods as well.

Obviously, this is only a suggestion, as your photo doesn't show close up detail, but L.incana is supposedly one of the commonest lichens to be found on this sort of habitat in Britain.

Regards,
Mike.

[SAHop]

If the lichen is not the problem, could it be high nitrogen levels causing the tree deaths and all the other devastation in my area - conifers all yellow or brown and dead, box hedging dying, bright orange/yellow fields, tree trunks rotting, causing trees to break or fall, other trees standing totally bare (not just of leaves which would be normal in the winter, but also of any smaller branches or twigs), ivy dying as it climbs affected trees, moss shrivelling and falling off roofs and walls only to be replaced by ... the yellow lichen, my usually very mossy front lawn now has bare patches and I am now really worried that there is something awful going on. The birds are struggling to nest as the branches have no twigs to rest the nest in. they have resorted to nesting where the large main branches grow from the trunk but even then some of the branches fall from under them. And it's not because of the harsh winter -this started in August last year.