Forestry Advance Access originally published online on March 21, 2005
Forestry 2005 78(2):109-120; doi:10.1093/forestry/cpi011
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A review of the relative roles of silviculture and tree breeding in tree improvement: the example of Sitka spruce in Britain and possible lessons for hardwood breeding
Forest Research, Northern Research Station, Roslin, Midlothian EH25 9SY, Scotland
** Corresponding author. E-mail: jason.hubert{at}forestry.gsi.gov.uk
Research involving the silviculture and genetic improvement of Sitka spruce (Picea sitchensis (Bong.) Carr.) is the most advanced of any tree species in Great Britain. Best practice advice and improved planting stock material are now available as growers attempt to maximize their returns according to their objectives. This paper reviews the various advances made in silvicultural and tree breeding research and summarizes the main lessons that have been learnt and the time scales involved. From this analysis it is possible to gain a clearer picture of the limits that silviculture and genetic improvement have for further tree improvements. The need for a combined approach in order to maximize the benefits of good silviculture and genetically improved material is emphasized. Recommendations have then been proposed for hardwood tree improvement in the light of the experience with Sitka spruce. In particular, there is the need for silviculture and tree breeding to address improvement of timber quality rather than purely vigour, and the use of parallel breeding strategies to enable improved material to come onto the market as quickly as possible. The need to make greater use of registered seed stands and untested clonal seed orchards, based on plus trees, as well as a more thorough system of progeny testing and selection is also discussed.