My crab cherry tree has developed hard, glossy nodules on the trunk. These resemble amber. What does it mean?

Question

The tree is over 50 years old and produces a good crop of large crab cherries every year.

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Answer 1

It could be wood borers or cankers. Read on:

https://www.gardeningknowhow.com/edible/fruits/cherry/cherry-tree-leaking-sap.htm

https://www.gardeningknowhow.com/plant-problems/disease/weeping-amber-in-trees.htm