Oregon’s High Desert begins at the eastern foot of Pilot Butte and stretches to the east and south as vast, sage-covered plains. Though it can appear monotonous at first glance, it contains complex ecosystems supporting hardy plants and animals unique to the cold deserts of the Northern Great Basin. Western juniper is the predominant tree, and numerous varieties of sagebrush alternate with lush native bunchgrasses to form a mosaic of plant communities that support the birds, animals, and people living east of the Cascades. Before Euro-American settlement, fire swept through about every 20 to 40 years, reducing sagebrush and junipers while increasing resilient bunchgrasses. Over the past 100 years, human impacts have increased shrubs and junipers, including the many young junipers on the north flank of Pilot Butte, and have introduced noxious weeds that threaten native species on the Butte and in Central Oregon.