It is (Shhhhh!) the oakmoss you are smelling in the drydown. And now I am going to say something that will probably make you all laugh: as inexpensive and as available as Jacomo fragrances are, Silences bears similarity to many good old chypres partly due to its ending -- O de Lancome, #19, Diva, etc.
Note: despite the word "Paris" on the box, Jacomo is an American designer!
Another note: while buying Silences, please pay attention to the color of the bottle -- the solid black color indicates the newer versions, while the older ones used to come in a grey bottle with black vein-like lines. There are some differences between the newer and the older formulations.