Why can repeated grazing or fire increase new growth in grasslands?

Repeated grazing and fire increase new growth in grasslands primarily by preventing the accumulation of a thick layer of dead plant litter. When this layer is allowed to build up, it creates several obstacles to productivity:1

• Nutrient Sequestration: It traps nutrients in a form that is not immediately available to the roots.1
• Physical Barrier: It acts as a physical obstruction, hindering new shoots from reaching the light as they grow from the soil surface.1
• Thermal Insulation: In temperate grasslands, this layer insulates the ground, which slows the warming of the soil during the spring.1

Furthermore, grasses are uniquely adapted to survive these disturbances because their growing points, or meristems, are located at the base of the stem near the soil, rather than at the shoot tips. This positioning protects the meristems from being destroyed by fire or grazing, allowing the plants to regenerate quickly. By removing the dead litter and clearing the way for new shoots, these disturbances help maintain the grassland ecosystem and prevent it from transitioning into other vegetation types, such as forests or shrublands.21