Seed and litter fall in Chusquea quila (Poaceae : Bambusoideae), after synchronous flowering in south-central Chile

Since 1989, the synchronous flowering and death of the bamboo Chusquea quil a (Poaceae,Bambusoideae) has ocurred over more than one million hectareas o f forest in southern Chile. We took advantage of this event to estimate the production of bamboo seed and litter during this period. The study area wa s the San Martin Experimental Forest of the Universidad Austral de Chile (3 9 degrees 38'S; 73 degrees 07'W), in San Jose de Ia Mariquina. The forest c anopy is composed mainly of Tepa (Laurelia philippiana), Olivillo (Aextoxic on punctatum), Roble (Nothofagus obliqua), Ulmo (Eucryphia cordifolia), and myrtle trees. Twenty three 0.125 m(2) collectors were distributed at rando m in the understory under dense cover of flowering Chusquea quila. Litter a nd seed production and seed viability were determined in the laboratory. Th e dispersal of Chusquea quila seeds began in December and reached ifs peak in early January, with a maximun of 51.3 x 10(6) +/- 44 x 10(6) seeds/ha (m ean +/-SD). Seed viability was highest between December and early March wit h 61 to 89% of viable seeds. In contrast, asynchronously flowering individu als had only 5% seed viability. Litter and seed production reached 3.1 t/ha during a period of 8 months. This production of litter is significantly hi gher (> 200%) than litterfall during vegetative growth periods of Chusquea quila.