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WIND STABILITY FACTORS IN TREE IMPROVEMENT PROGRAMME

Objective

To improve the stability of fast growing conifer crops and thereby increase the productivity of forests in the EC by:
quantifying the effects of tree improvement programmes on the stability of Norway and Sitka spruce;
quantifying the contribution of stability characteristics to tree anchorage as determined under dynamic and static loading.
In the first part of the study the effects of provenance and silvicultural practice (wide spacing) on stem quality, branching characteristics and basic wood properties of Betula pendula, Fagus sylvatica, Fraxinus exelsior and Querqus robur/petraea were studied. It was found that greater growth was achieved in all species through wider spacing. Wider annual growth rings appear to have minimal effect on density and shrinkage and the length of clear stem appeared to be little affected. It was also found that the internal quality of wood was positively influenced by fast diameter growth. In the second part of the study it was shown that the machining properties and surface quality of sawn timber were unaffected by diameter growth in all species. The results of the investigations into Populus clones show that there are significant differences between clones in volume production as well as in wood quality, particularly in branch diameter and angle.
The project is divided as follows.

The root architecture of clones and progenies of Norway and Sitka spruce will be determined. Root growth geometry will be quantified by dividing the root system into eight equal sections and estimating the dry weight of each section.
Root/shoot ratio: this parameter will be measured at all sites for progenies and clones of Norway and Sitka spruce.
Stemwood and rootwood strength: bending strength, modulus of elasticity in bending, tensile strength, extension to breakage and the tensile modulus of elasticity of wood will be estimated. Density, ring width and percent early and late wood will be measured. Correlations between stemwood and rootwood properties will be calculated for the different progenies.
Soil from all the experimental sites will be classified according to particle size distribution. This will provide insights into the difference in behaviour of organic and mineral soils when subject to repeated loading.
Anchorage: maximum turning moment will be estimated for clones and provenances of both species. The behaviour of the root plate during winching will be recorded as will the size and shape of the upturned rootplate at the end of the test.
Trees will be subjected to dynamic loading using a tree rocking device.
Crown architecture will be assessed in Norway spruce. The data will be used to derive sail area and to estimate bending moments at the base of the stem for a range of wind speeds.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Coillte Teoranta
Address
2,Sidmonton Place
26 Bray, County Wicklow
Ireland

Participants (4)

Den Kongelige Veterinær- og Landbohøjskole
Denmark
Address
23,Rolighedsvej
1958 Frederiksberg C
FORESTRY COMMISSION RESEARCH AGENCY
United Kingdom
Address
Northern Research Station
EH25 9SY Roslin-midlothian
Institut National de la Recherche Agronomique (INRA)
France
Address
Ardon
45160 Olivet
University College Galway
Ireland
Address
University College
90 Galway