In essence, Treesong is a violin concerto, but maybe Williams felt that calling it Violin Concerto No 2 was a bit abstract and wanted to convey the inspiration in the title. Although in three movements, the typical concerto structure is somewhat altered with a more exciting central movement surrounded by more introvert opening and closing movements. The soloist is also highlighted even more than one might expect and not always supported by other instruments. There are long cadenzas when no one else is playing and even when they are supporting, the orchestration is sparse and subdued. Only for a brief moment almost exactly halfway through is there a vibrant orchestral outbursts. The final movement is less abstract than the others, the lyricism becoming more evident.
The Violin Concerto itself has been criticised as quite stark and uninvolving, which is a difficult and surprising opinion to accept of something by Williams, but in some ways it's true. Having said that, Treesong I didn't find especially emotional - one would expect something rhapsodic and what Williams has written is a little more abstract. The Concerto itself has the benefit of what essentially boils down to more notes. The orchestra has a lot more to do and there are great swells in tempo and volume and in the opening movement, the spiky violin melody is carried along on a firmer orchestral bed. This version represents a 1998 revision of the 1970's original, which was written in memory of Williams' late wife. It is perhaps this that explains why the Peaceful Contemplation of the second movement seems so anguished, certainly for most of its run time - the closing minutes are somewhat more restful. The final movement opens with a more traditionally Williams style of writing, broad fanfares and some quite dynamic orchestral fireworks, although again, he seems reluctant to give in totally to romanticism and there is always an undercurrent of disquiet - harmonies don't quite resolve as expected and the melody occasionally goes off in expected directions. However, a rousing finale.
The selections from Schindler's List seem a little like unnecessary padding, but do emphasise the difference in style of his concert and film music. Of course the performance of the haunting main theme and the, perhaps, even more emotional Remembrances are excellent, although don't really improve on the original with respect to either soloist or orchestra. Shaham's playing is of course skilled and emotive throughout, he evidently collaborated with Williams to achieve the best performance that composer and soloist could muster. The two concertos are perhaps a little more difficult to warm to than his other concert music, there is a certain lack of lyricism in the writing and even the exciting passages are prickly and difficult. This does not make it bad of course and from a technical stand point, they are extremely well wrought compositions. The Boston Symphony perform with predicted excellence and the liner notes are insightful.
Rating ~ 
Treesong
Concerto for Violin and Orchestra
Three Pieces from Schindler's List
Total Time ~ 66:05