Sap is the life force running through a tree, so tradition reads it as vitality and renewal rising after a dormant time. Sticky sap also stands for situations that are hard to get free of.
When this appeared in your dream, what were you feeling?
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.