Tree experts (arborists) look for U-shaped and V-shaped branches when making pruning decisions. That’s because one is MUCH stronger than the other.
Do you know which one is stronger and why?
If you said U-shaped branches, you’re correct.
Here’s why. The union where two branches (or a branch and the main tree trunk) come together ideally allows for the growth of specialized wood under the branch bark ridge.
The branch bark ridge wood limits the movement of disease and water from one branch to the other, should one of the branches become diseased or wounded.
The V-shaped branches (B in the image) provide little space for branch bark ridge growth, increasing the chance for decay. The bark ridge that does develop is soon over-grown by the branch wood, making for a very weak union.