Fruits and Nuts: How NOT to prune a tree 4: Oh No! Geometry!, 0 by pollengarden

pollengarden wrote:
More recent research has shown that branch angle isn't the only factor that determines the strength of the branch. Branches should be LESS than half the diameter of the trunk. Branches of this smaller diameter develop alternating layers of trunk and branch tissue where the two meet, making a stronger union. Larger branches that are OVER half the diameter of the trunk tend to develop a single continuous layer of tissue where the trunk and branch meet, which isn't as strong as the double alternating layers.

The branches of the tree in the photo were trained out to 45-60 degrees when the tree was young. However, the branch on the left is too large - the smaller branches on the right side are actually stronger.

The following is the source of my information, with illustrations of how the tree tissues develop where the branch meets the trunk:
http://www.cmg.colostate.edu/gardennotes/612.pdf