The House Group of Giant Sequoia trees (Sequoiadendron giganteum, Sierra redwood, Sierran redwood, or Wellingtonia). World's largest trees in terms of total volume; grow to avg. 160-279 ft (50–85m) tall and 20-26 ft (6–8) in diameter; record trees to 311 ft (94.8m) tall and over 56 ft (17m) in diameter. Sequoia National Park, est. 9/25/1890. 404,051 acres (1,635 km2). Giant sequoia forests are part of 202,430 acres (81,921 ha) of old-growth forests shared by Sequoia and Kings Canyon. National Parks. Thousands of trees cut in late 1800's. Sequoia trees splinter easily and found to be unsuitable for timber harvesting. Tulare County, CA.