Q.Fig Tree Bark Cracking
My fig tree gets plenty of sun in the Bay Area, California backyard of the house. It’s got a lot of cracking and peeling of little squares in the center of the trunk where it breaks off into two large branches. The cracking is going up one of the branches. What can I do to stop this?

The important part of stopping the condition is figuring out what is causing it. It's not a common disease of fig trees, as you can see from this article: https://www.gardeningknowhow.com/edible/fruits/figs/common-fig-tree-diseases.htm
However, it does sound like it could be potentially dangerous to the tree. Here's a general article on peeling tree bark: https://www.gardeningknowhow.com/ornamental/trees/tgen/peeling-bark-on-trees.htm
It would be to your advantage to get a professional diagnosis, either from a certified arborist, or from the County Extension Service. This link will help you locate the nearest office: https://www.gardeningknowhow.com/extension-search/