A network of 18 permanent plots in Mount Rainier National Park (MRNP) (Figure 1) is being monitored to provide data on long-term trends in mature and old-growth forests in the Abies amabilis (Pacific silver fir) and Tsuga heterophylla (western hemlock) vegetation zones. The plots were established across a range of elevations and geographic locations in the late 1970’s under the direction of Dr. Jerry Franklin (University of Washington). They are currently managed through the Pacific Northwest Permanent Sample Plot Program at Oregon State University in collaboration with the University of Washington, the US Forest Service, the National Park Service and others. The plots are censused every five or six years, providing long-term records on rates of tree growth, the causes and characteristics of tree mortality, and fine-scale spatial patterns associated with tree recruitment and mortality. These data help quantify levels and dynamics of natural forest structures, provide the definitive measure of long-term forest productivity, and provide a basis for monitoring effects of global climatic change on forests.