Mountain Brook was made with luminism style. This painting is a quiet woodland scene in White Mountain of New Hamsphire, in contrast; the Civil War was raging across all the country. Therefore with his bird and landscape, he wanted to represent the nature's silent beauty; and during the Civil War, it represented nature as a silent witness to battlefield devastation.
Albert Bierstadt (January 7, 1830 - February 18, 1902) was a German-American painter best known for his large landscapes of the American West. In obtaining the subject matter for these works, Bierstadt joined several journeys of the Westward Expansion. Though not the first artist to record these sites, Bierstadt was the foremost painter of these scenes for the remainder of the 19th century.
Bierstadt was part of the Hudson River School, not an institution but rather an informal group of like-minded painters. The Hudson River School style involved carefully detailed paintings with romantic, almost glowing lighting, sometimes called luminism.
Bierstadt was born in Solingen, Germany. His family moved to New Bedford, Massachusetts, in 1831. He developed a taste for art early and made clever crayon sketches in his youth. In 1851, he began to paint in oils. He returned to Germany in 1853 and studied painting with the members of the Düsseldorf school of painting in Düsseldorf until 1857. He came back to New Bedford and taught drawing and painting briefly before devoting himself to painting.
Map of Bierstadt's journey in 1859 and 1863.In 1858 he exhibited a large painting of a Swiss landscape at the National Academy of Design, which prompted positive critical reception and honorary membership in the Academy. At this time Bierstadt began making paintings in New England and upstate New York. In 1859, he traveled westward in the company of Frederick W. Lander, a land surveyor for the U.S. government, and returned to a studio he had taken at the Tenth Street Studio Building in New York with sketches that would result in numerous finished paintings. In 1863 he traveled west again, this time in the company of the author Fitz Hugh Ludlow, whose wife he would later marry. Throughout the 1860s Bierstadt used studies from this trip as the source for large-scale paintings for exhibition. He continued to visit the American West throughout his career.
During the American Civil War, Bierstadt paid for a substitute to serve in his place when he was drafted in 1863. He did complete one Civil War painting Guerilla Warfare, Civil War in 1862, based on his brief experiences with soldiers stationed at Camp Cameron in 1861. Bierstadt's painting was based on a stereo photograph taken by his brother Edward Bierstadt, who operated a photography studio at Langley's Tavern in Virginia. Bierstadt's painting received a positive review when it was exhibited at the Brooklyn Art Association at the Brooklyn Academy of Music in December 1861, however, Curator Eleanor Jones Harvey observes that Bierstadt's painting, created from photographs, "is quintessentially that of a voyeur, privy to the stories and unblemished by the violence and brutality of first-hand combat experience 
Guerilla Warfare, Civil War by Albert Bierstadt, 1862Bierstadt's technical proficiency, earned through his study of European landscape, was crucial to his success as a painter of the American West, and accounted for his popularity in disseminating views of the Rockies to those who had not actually seen them. The immense canvases he produced after his trips with Lander and Ludlow established him as the preeminent painter of the western American landscape.