In the high elevations of the central and southern Appalachians and upper latitudes of the northern Appalachians, red spruce (Picea rubensRed spruce ()) is an important species that has a unique life history as a slow-growing, shade-tolerant tree that grows in cool, moist conditions. In this chapter, we cover multiple aspects of red spruceRed spruce () biology. We describe red spruceRed spruce ()’s reproductive strategy, how that influences its ecology, and how red spruceRed spruce ()’s biology influences its forest structureForest structure and stand dynamics. Both biotic and abiotic stressorsAbiotic Stressors can affect physiologyPhysiology, growth, and mortality of red spruceRed spruce (). We examine how the major biotic (i.e., native and invasive insects) and abiotic (e.g., acid rain, air pollutionAir pollution) stressors impact red spruceRed spruce () stand dynamics. We also characterize the genetic diversityGenetic diversity of the species across its range. Understanding the basic biology of red spruceRed spruce () is important for determining how to manage and conserve the species, especially with rapidly changing climates.