Q.Split in bark of apple tree ‘James Greaves’
I have a young apple tree which has developed a split running vertically in the bark at the point of the tree where the branches appear. The tree is quite young (not sure of its age) but it was new when I was given it 3 1/2 years ago. Help, please.

Here are 2 excellent articles for you with several tips.
https://www.gardeningknowhow.com/ornamental/trees/tgen/cracking-tree-trunks.htm
http://plantclinic.cornell.edu/factsheets/barksplitting.pdf