In this study one aspect of an investigation on the ecology of surface dwelling Collembola in a pine forest is reported. The population structure of six species has been examined and data have been col- lected about natality, growth and mortality in these populations under field conditions. Since very little autecological work has been done on this group, little is known about seasonal fluctuations. In a few cases only the winter populations have been studied, but exclusively of soil-Collem- bola.