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Forest Research home > Research > Forest management > Regeneration and sustainable silviculture > Seed and seedling biology > Tree seed storage and pretreatment

Seed pretreatment of deeply dormant species

Examples: Most broadleaves e.g. ash, beech, cherry

A few conifers e.g. juniper and yew.

Overview

All these seeds (whether freshly collected or stored) are incapable of germinating under any conditions until pretreated. Pretreatment consists of incubating seeds for a relatively long period of time (8 to 64 weeks) under moist conditions. All species can be pretreated either naturally or artificially. All can be pretreated in a moisture retaining medium, a few can be pretreated without. Some need cold only (c. 4°C) others warm (c. 15°C) followed by cold (c. 4°C) - for recommended pretreatment durations for individual species - seed pretreatment tables.

Methods

There are several potential methods which can be used to pretreat deeply dormant seeds. Three are described below:

  • Easy: Natural (outdoor) pretreatment/germination with medium for deeply or shallowly dormant tree seeds
  • Moderately easy: Artificial (temperature controlled) pretreatment/germination with medium for deeply or shallowly dormant tree seeds
  • Skilled: Artificial (temperature controlled) pretreatment without medium for deeply or shallowly dormant tree seeds.