Rotten wood looks solid until it gives way, so it is read as hidden weakness or neglect. Dream books also see it as decay making space for something new to grow.
Where in your waking life have you met something like this lately?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.