Gray pine, incense-cedar, and California black oak grow in abundance. Many examples of red-barked manzanita can be seen along the Hetch Hetchy Road. Spring and early summer bring wildflowers including lupine, wallflower, monkey flower, and buttercup. Seventeen species of bats inhabit the Hetch Hetchy area, including the largest North American bat, the western mastiff. Before damming, the valley floor contained abundant stands of black oaks, live oak, Ponderosa pine, Douglas fir, and silver fir bordering the meadows, with alder, willow, poplar and dogwood in the riparian zone along the Tuolumne River. The valley's abundant plants provided nourishment for mule deer, black bears and bighorn sheep. Due to large cataracts on the Tuolumne River upstream, Hetch Hetchy Valley may have been in the uppermost range for native rainbow trout in the river. Due to its abundant wetlands and stream pools, Hetch Hetchy was notorious among early travelers for becoming infested with mosquitoes in the summertime. Said San Francisco resident William Denman in 1918, "The first time I went into the Hetch Hetchy the mosquitoes were intolerable. They would light upon a man's blue shirt and turn it brown, and were voracious as mosquitoes would be." History Indigenous peoples People have lived in Hetch Hetchy Valley for over 6,000 years. Native American cultures were prominent before the 1850s when the first settlers from the United States arrived in the Sierra Nevada. During summer, people of the Miwok and Paiute came to Hetch Hetchy from the Central Valley in the west and the Great Basin in the east. The valley provided an escape from the summer heat of the lowlands. They hunted, and gathered seeds and edible plants to furnish themselves winter food, trade items, and materials for art and ceremonial objects. Today, descendants of these people still use milkweed, deergrass, bracken fern, willow, and other plants for a variety of uses including baskets, medicines, and string. Meadow plants unavailable in the lowlands were particularly valuable resources to these tribes. For thousands of years, Native Americans subjected the valley to controlled bushfires, which prevented forest from taking over the valley meadows. Periodic clearing of the valley provided ample space for the growth of the grasses and shrubs they relied on, as well as additional room for large game animals such as deer to browse. In the 19th century, the first white visitors to the valley did not realize that Hetch Hetchy's extensive meadows