Bob and Danny Weller's Tree of Thorns combines elements of contemporary jazz with experimental improvisation and 20th century harmonic language. Featuring Bob on piano and Danny on bass, the album showcases the two in a number of settings: straight-ahead jazz trio, with drummer Cliff Almond; experimental think tank; groove machine; or melodic "painters" (listen to Arise).
Tree of Thorns has one dominant theme: dark energy. The first track, "Cranning Call," features this in many forms: dark 5/4 groove, dark melodic shape, dark harmonies, not to mention a very dark exchange of ideas between the three during the solo section. Track 2 follows suit, with a different groove and more traditional jazz harmonic approach. Track 3 relaxes the mood a little bit and sets the stage for some more traditional straight ahead tracks, including standards such as Footprints and Yesterdays. Starting with track 9, a free improvisation featuring Bob, with Ellen with a rubato performance of Arise, one of the first melodies that Danny ever composed. For Bob and Danny, this last track is very symbolic of the way that the two have influenced each other very closely as developing musicians over the years.