The alder grows with its roots in water, so dream books read it as standing firm among strong emotions. Its wood turning red when cut ties it in folklore to hidden passion.
Does the traditional reading fit your dream, or did it mean something else to you?
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.