Stand structure and aboveground biomass partitioning in three populations of Calamagrostis arundinacea

Three populations of Calamagrostis arundinacea, i.e. a population developed in a dying forest and two populations on clearing sites (referred to as young and old) were studied in the area under air-pollution impact in the Moravian-Silesian Beskydy Mountains. A higher density of small tussocks (about 5 cm in diameter) was characteristic for the young clearing population. In the forest and old clearing populations larger tussocks (20-25 cm) were also present. The average total aboveground biomass was very low in the forest population (37 g.m-2 ), while in the young and old clearing populations it was more than ten times higher (419 and 510 g.m-2 ). Flowering shoots formed 3.3 and 8.1% of the total number of shoots and 10.8 and 21.4% of the aboveground biomass in the forest and old clearing populations, respectively. In the young clearing population in an open disturbed habitat, a larger percentage of biomass was allocated to flowering shoots and inflorescences represented, respectively, 74-84% and 7-8% of aboveground biomass of tussocks (5-15 cm in diameter). 55.4% of the aboveground stand biomass was formed by flowering shoots.