The Suonenjoki Unit was established in 1968 for forest tree nursery studies and forest regeneration studies. The research unit manages also the research nursery, producing a total of 1-2 million tree seedlings for Metla's own forests and also for other customers.

In addition to research activities, the research unit is responsible for inspection the biological efficiency and applicability of all the pesticides to be used in forestry.

The research unit also provides various information services for the information end users. For example, the information service for forest tree nurseries is widely recognised.