Of all the answers to the question of what American music actually is, I find the most satisfying one to be that it is music written in America (attributed to Aaron Copland, as quoted by Van Dyke Parks). America's landscape is extremely varied, and over the course of history, has had spots of breathtaking natural beauty. Coming from the East coast, and living in the Midwest, I have only lived with certain kinds of American natural beauty, and certain kinds of American urban beauty within my (almost 50 year) lifespan. The rest I get through images and sounds. Lately, partly due to my time spent with Amy Beach's music, how much a composer's music reflects the physical environment where s/he lives and writes.
I have always been particularly attuned to sense of "place." I remember one backstage conversation I had (in Illinois) with Peter Bowman, the principal oboist of the St. Louis Symphony. We were talking about beautiful places in New England. I mentioned that the most beautiful spot I knew was the area between New Hampshire and Vermont, around Keene and Brattleboro. It is the place where I imagine Peyton Place was set, and an area where I once spent a glorious week in May (the 13th-23rd, to be exact) watching the lushness of Spring take over the mountains. It turned out that Peter grew up in that area. Amy Beach did too.
I have always loved Gene Stratton-Porter's "Limberlost," as described in A Girl of the Limberlost and her many other writings, both as a naturalist and as a fiction writer. There are still remnants where I live of what used to be the general landscape of downstate Illinois and Indiana when it was mostly swampland. I have come to appreciate the beauty of the flora and fauna in my area, though the richness of the flora and the fauna that existed during the 19th century floods my imagination, as it flooded the canvases of the painters from the Hudson River School of painting.
To my ears, our 19th-century American music preserves the lush beauty of the 19th-century American landscape in sound, particularly in the music of Edward MacDowell, Amy Beach, Sidney Lanier, Arthur Foote, Charles T. Griffes. There are, of course, American composers, like Louis Moreau Gottshalk, who take their emotional material from other sources, sources which are just as uniquely American as the natural physical landscape, but lately, after a lifetime (or half a lifetime--I'm hoping for another 50 years) of trying to figure out just what it is that I "recognize" in American music from the 19th century, these images help me to understand something about American Romanticism.
These 19th-century composers breathed the same air as their Hudson River School contemporaries. They traveled down the same unpaved roads, using the same rhythmic means of locomotion (foot, horse, or train), and experienced some of the same sounds of nature, like the sounds coming from the bird life. (Sibelius believed that bird life had a great influence on music from different parts of the world. I think that he was certainly onto something.)
It is easy to play 19th-century American music and concentrate on the elements that we recognize from 19th-century European music. After all, the musical materials are often the same. But the danger of going for what we recognize in the music of Brahms, Schumann, Mendelssohn, and other 19th-century composer who set standards for American composers who studied their music, is that we can cause the music to sound derivative, like Faux Faure. By taking a walk outside, in an undeveloped spot, or going to the 19th-century American wing of an art museum (for people who do not live in America), perhaps we can get a passing whiff of what might get at the heart of the sound of American music in the 19th century.