How did Richard Strauss orchestration reflect him as a 20th century composer?
I’m not sure that I would agree with the assumption that Richard Strauss’ orchestration is indicative of the fact that he lived in the 20th century. Strauss was an enormously gifted orchestrator. He wrote out full scores without using a piano score first. Most composers (even Mozart at times) would use a piano score. I guess the most modern thing about Strauss’ orchestration is his use of extended techniques: extremes of range (horn in Symphonia Domestica; flute top C; violins to top G in Zarathustra), flutter tonguing (woodwinds and brass in Don Quixote), a mechanical device to pump air into the woodwinds mouths so they can hold really long notes (!) (Alpensymphonie–opening). There are extremely demanding parts for all the instruments. Strauss expanded the orchestra to a huge size. He used instruments seldom seen in the orchestra: tenor tuba (Don Quixote), oboe d’amore (Symphonia Domestica) Heckelphone (Alpensymphonie) Wind Machine (ibid.) He added to section numbers: 2 tubas in Zara