The productivity of stands of C. culeou and C. tenuiflora wa s studied developing a methodological basis for future ecological studies of Chusquea spp. The phenology of the two species and the habitat condition of study sites are described. The standing above ground biomass for C. culeou wa s estimated as 156-162 t ha-1 and represented that of the whol e community since no other species wer e present in significant quantities. For. C. tenuiflora the standing biomass of 13.0 t ha-1 account for most of the biomass of the understorey but only for a small fraction on the total standing biomass of the mixed Nothofagus forest under which it grows. Th e annual dry matter production in the C. culeou thicket determined as the sum of annual leaf fall (4.27 t ha - 1 ) and the biomass of one year old culms ammounted to 10-11.4 t ha-1 . The magnitude of the net primary production of C. tenuiflora is suggested by the 1.0 t ha-1 of new culm growt h per year. Th e above ground biomass of 156-162 t ha-1 estimated for the C. culeou thicket is greater than the values reported for many forests and the estimation of annual primary production 10- 11.4 t ha - 1 ) for the C. culeou stand lies between the average values reported for boreal forests and temperature forests.