Tree breeding
Although tremendous advances have been made over the centuries to domestic livestock, arable crops, horticulture and fruit through selective breeding, improvement of timber crops has lagged behind. This is partly a reflection of the longer life cycle, making it inherently difficult to achieve rapid improvement in the quality or quantity of timber produced in long-living organisms. Traditional selective tree breeding has been used to improve fruit trees for years; it is now being applied to trees for timber. Plant breeders are now using controlled fertilisation between selected "super" trees and vegetative propagation to produce a range of better trees for forestry. Factors selected for may be growth rates, disease resistance, stem straightness and wood fibre quality. Examples are:
(a) A native of the northwest of North America, Sitka spruce is the most important species in upland forestry in Britain. Research and development projects have been boosting the growth rates and timber yields by making genetically improved planting stock available to 
the grower.Crossings or intermatings can produce seeds and cuttings from them selected for the greatest potential genetic gain in terms of vigour, health, form and wood properties. Stem cuttings of these super seedlings are taken and multiplied or bulked up. Several million improved Sitka spruce cuttings are taken each year which are then planted in rooting medium, grow roots and can then be planted out in the forest.
(b) New varieties or clones of poplars are on sale which grow faster, can be harvested earlier and are resistant to common diseases.
(c) The search is on to breed types of English elm resistant to Dutch elm disease.
(d) New to the market are varieties of cherry for growing timber rather than fruit. In recent years, micro-propagation of trees has become common practice. Taking small samples of live plant material and culturing them in the laboratory to produce individual plants has become common practice. This means that a large number of individual plants can be produced from one selected parent. These in vitro techniques are important in producing trees with special characteristics and for bulking up specimens of rare or endangered plants.
More:
Click on Trees by Species for information on the trees mentioned above.
The Royal Forestry Society supports the British and Irish Hardwoods Improvement Programme (BIHIP) - a partnership of landowners, research institutions and professionals combining forces to achieve better quality and growth in ash, wild cherry, oak and walnuts.
FC Info. Note 26 (1999) "Predicted Genetic Gains from Sitka Spruce Production Populations" by S. Lee. FC Info. Note 27 (1999) "Genetic Gain from Scots Pine: Potential for New Commercial Seed Orchards" by S. Lee. FC Info. Note 59 (2004) "Advances in Biotechnology: Powerful Tools for Tree Breeding and Genetic Conservation" by S. Lee.