Hello, how are you? Well basically looking at the image the problem there is the wood that with temperature changes expands and contracts, and it is a different expansion and contraction than the bricks, therefore these cracks appear in the absence of an element of cushioning between materials. I recommend you to put around the wood some sealant that allows the expansion and contraction of the wood, something based on polyurethane. You can also open the space around the wood and put expanded polystyrene (Styrofoam) that cushions these expansions and contractions between different materials. I am not thinking that you should hire me, I just hope my help will be useful.
On the other hand, also note that the breakage is made by the material less resistant to traction, which is the cement. The brick is more resistant to traction, that is why it does not break there.
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Arch. martin Alegre