During the growing season livestock will often selectively graze the highest moisture sites, especially in drought years. This means that livestock can be present on Aspen Parkland fields during the growing season, and depending on the barrier presented by decadent aspen forest, will selectively not graze parkland fescue grassland until the forage on higher moisture sites has been depleted. Growing season grazing of native Aspen Parkland does not necessarily have deleterious effects, if livestock are selecting for high moisture sites. Operations that have only native parkland as a forage base can achieve good seasonal grazing by rotating fields that are grazed during the growing season, starting and ending the grazing season in a different field every year. Operations that have a mix of tame and native forage should graze the tame during the growing season and save the native fields for fall grazing or for use as emergency forage.
Plants require rest between grazing to replenish stored sugars and restore leaf area.
A general rule of thumb for rest in the parklands is 35 days rest between grazing for tame pastures and longer rest periods for native pastures. Unless native fields are managed using selective grazing, they should be grazed only once per year. Tame pastures can usually be grazed twice per year depending on rainfall. In drought years problems with lower than average forage production are compounded by the need to increase the rest period. Emergency forage may have to be used to achieve adequate rest during severe droughts.