A log is a tree reduced to its essence, read as raw potential and stored energy. Lying across a path it is an obstacle; floating it stands for being carried by events.
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.