Mt. Rainier’s old growth forests are a critical natural resource. Nearly 60% of the Park is forest, providing important habitat for many plants and animals including some endangered species such as northern spotted owl. Old growth forests provide other value ecosystem services through carbon sequestration and air quality improvement. Enormous trees, such as the Grove of the Patriarchs, inspire and awe park visitors, providing a rare example of what ancient landscapes may have looked like across the Pacific Northwest. Furthermore, through their annual rings, these giants record the histories of their growth responses to past climate and can provide valuable insights into how forests may respond to changes in climate in the future.