Forest pathogens are usually, but not always, microscopic organisms that attack trees in ways that can be hard to see with the naked eye. Pathogens can destroy roots and so reduce water and nutrient uptake. They can cause cankers or wilt diseases that reduce the flow of water to the leaves or needles. They can cause leafspots and defoliation that reduce the tree's carbohydrate reserves and its likelihood of surviving a hard winter.
US Forest Service R&D studies non-native and native pathogens that significantly affect U.S. forests, and the many different forest functions people value: clean air, water, timber, aesthetics, recreation and other non-forest product commodities.
Select a link below to learn more about our research on these important forest diseases.