In this paper we present evidence supporting the premise that forest nutrition, nutrient cycling and nutrient management are critical factors for the health of Inland Western forests and for management of the ecosystems. The current state of knowledge suggests that inadequate tree nutrition, particularly potassium shortage, influences tree chemistry such that inadequate plant defensive compounds are produced. Pathogens and insects are unusually successful in attacking such trees. Forest managers have substantial influence on the forest nutritional environment through nearly all types of silvicultural treatments.