The uptake of nutrient and water by the cluster roots peaks through winter and spring, but ceases when the upper layer of soil dries out in summer. The cluster roots are then allowed to die, but the laterals are protected from desiccation by a continuous supply of water from the sinker root. The water supplied to the laterals by the sinker root is continually lost to the soil; thus this plant facilitates the movement of ground water from the water table into surface soil, a process known as hydraulic redistribution. Cluster roots have been estimated as comprising about 30% of total root biomass in this species; the seasonal production of so much biomass, only for it to be lost at the end of the growing season, represents a substantial investment by the plant, but one that is critical in the competition for nutrients.