I was never happy with the Sawmill picture, so it's gone!
I came across this little sapling growing in the most inhospitable of places, but it looks like it's been there a few years. May it's roots grow deep and let it grow to a grand old age.
This is a good one. I try to plant a tree, nurture it, feed it, water it, shelter it and it shrivels up and dies. Here on the edge as you say, it pushes up through rock and cracks to grow. Yvonne