I think that dark mark at the top is indication of disease – a fungus has got in fairly recently (because it’s near the outer part of the trunk, which is the newer wood) and has killed some of the wood but the tree has fought back before the damage has gone any further.
I think the other dark mark indicates the start of a new branch, just like you say.
Why is the centre of the tree not quite in the centre?
scienceoutdoors 
I think that dark mark at the top is indication of disease – a fungus has got in fairly recently (because it’s near the outer part of the trunk, which is the newer wood) and has killed some of the wood but the tree has fought back before the damage has gone any further.
I think the other dark mark indicates the start of a new branch, just like you say.
Why is the centre of the tree not quite in the centre?
PS It’s FIR, not FUR…
LikeLike