ash

Ash is the residue left after combustion of organic matter. It is primarily mineral in composition and varies with the fuel and burning conditions. Wood ash, produced by burning wood, is typically alkaline and rich in calcium carbonate, potassium carbonate, and trace minerals. Historically, ash has been used as a soil amendment, in glassmaking, and in soap making.

In botany, ash refers to the genus Fraxinus, a group of deciduous trees in the olive family native to the temperate regions of the Northern Hemisphere. Fraxinus species usually have opposite, pinnate leaves and produce winged seeds called samaras. The wood is strong and shock resistant, valued for furniture, cabinetry, and sporting goods such as baseball bats. Common North American species include white ash (Fraxinus americana) and green ash (Fraxinus pennsylvanica).

Ash trees face threats from pests and disease, notably the emerald ash borer (Agrilus planipennis) in North America and ash dieback caused by Hymenoscyphus fraxineus in Europe. These pressures have led to widespread mortality and active management, including monitoring, quarantine, and breeding for resistant trees.

The term ash also appears in culture and religion, where ash may symbolize mourning or purification in various traditions.