Posted: 29/07/2017 at 15:03
They both look fine to me ... yes the oak has a couple of dead twigs, but I don't think it's anything to worry about ... they might have snapped in a strong wind or with the weight of a heavy wood pigeon (not joking, it happens in our trees).
The other tree is a Common Elder ... it has some elderberries forming and these will be loved by the birds when they ripen ... and of course if you or anyone you know is into home winemaking they'll be great for elderberry wine. Next year you can use the flowers for elderflower champagne or elderflower fritters and other recipes you'll find online.
The slugs etc were probably around the base because as you said there were bushes there ... now you've got rid of the bushes I can't see any slugs there? The bark looks ok to me ... a bit damaged but if you leave it alone it should be fine. The orangey brown layer is perfectly normal.
Green stuff on the branches is probably lichen, which is an indication of good air quality and not harmful to the tree.