Wind River Experimental Forest, Washington. USDA Forest Service photo by Tom Iraci.
Old‐growth coniferous forests of the Pacific Northwest are among the most productive temperate ecosystems and have the capacity to store large amounts of carbon for multiple centuries. There are considerable limitations to the simulation models that have been used to explore this ecosystem. Some models simulate well stand composition and structure, which is a slow, long-term process. Others do a good job simulating forest interaction with the atmosphere, which is a very fast process that occurs by the minute and hours. Until recently, no model has done both things well in the Pacific Northwest.
To remedy this, John B. Kim, a research biologist, and his university colleagues applied the Ecosystem Demography Model 2 (ED2) to an old growth site in the Pacific Northwest. ED2 is a new model that has been primarily applied in the northeastern United States and the Amazon. Kim and his colleagues calibrated and applied ED2 to the Wind River Experimental Forest, Washington, a well‐studied old‐growth Douglas‐fir–western hemlock ecosystem. The model is able to reproduce observed forest composition and canopy structure, and carbon, water, and energy fluxes at the site. This enables explorations of how the forest responds to past, present, and future climate. The simulations quantify how the forest uses water on daily, seasonal, and annual time scales and identify patterns of response to hot, dry climate. The simulations allow exploration of how those fast physiological responses affect long-term stand composition and structure. This study lays a solid foundation for applying this next-generation dynamic vegetation model across the Pacific Northwest.