Seed and seedling biology

Summary

Placing Douglas fir seeds onto moist filter paper British forestry has been based on sowing seeds into the hospitable environment of a nursery, transferring the best seedlings to the forest planting site and several decades later clear-felling the resulting trees. Today there are many woodland managers who would prefer to use more natural processes in the creation and maintenance of uneven-aged and continuous-cover forests.

The aim of this programme is to improve the reliability of all methods of woodland establishment from seeds including:

Direct seeding
(Human assisted) natural regeneration
Traditional nursery sowing plus seedling establishment

Related information:

Storage, dormancy, pretreatment and germination of individual tree species
Detailed information for over 100 tree and shrub species
Publications and scientific papers

Background

Two methods are being increasingly employed, ‘natural regeneration’ (or more accurately ‘human-assisted natural regeneration’) and ‘direct seeding’, but are both proving to be much less successful and predictable at establishing trees than the traditional technique as:

There is an insufficient understanding of tree seed characteristics - for example what is the fate of most naturally dispersed or direct sown seed; what prevents or stimulates surviving seeds to germinate
Tree seed quality and performance lag at least 50 years behind that of agricultural, horticultural, vegetable and flower seeds
The factors affecting seedling establishment and survival are very poorly understood.

Research objectives

Firstly to evaluate and improve the reliability and success of all methods of woodland regeneration from seeds by:

Determining the fate of naturally dispersed and direct sown seed
Understanding what makes tree seeds germinate or not
Investigating establishment and survival of seedlings.

Secondly to increasing our understanding of the underlying processes of regeneration that are most likely to be affected by projected changes in climate, so that we can predict future impacts and deduce a strategy for adapting future seed sources and silvicultural systems.