The Effect of Summer Harvesting of Phragmites australis on Growth Characteristics and Rhizome Resource Storage

The effect of harvesting the aboveground biomass on the growth of Phragmites australis in the subsequent growing season was investigated following cutting in June or July. Seasonal changes in rhizome biomass and total nonstructural carbohydrate (TNC) in seven age categories, from newly formed to six-years-old, were monitored for the two treatment stands and a control stand. The growth of the stands, as indicated by the aboveground biomass, showed a significant decline due to cutting in June but did not show a significant difference due to cutting in July, compared to that of the control stand. The timing of harvesting of aboveground biomass affected the annual rhizome resource allocation. A similar trend was observed for the pattern of resource allocation, as described by biomass variation of different rhizome-age categories for July-cut and control stands. However, the biomass of June-harvested rhizome categories tended to be smaller than the other two stands, indicating substantially reduced resource storage as a direct result of harvesting the aboveground biomass during the previous growing season. This implies that cutting of aboveground biomass in June is a better option for control of P. australis stands than cutting later in summer.