Nicholas Davies edited Results.tex  about 8 years ago

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While the study was larger than preceding attempts, the sample number was still small when considering heritability calculations. The lack of data resulted in wide 95\% credible intervals, which require more samples to tighten. The heritability indicates that growth strain can be influenced by breeding, and are in line with the 0.32 reported by \cite{Murphy_2005}, they are significantly higher than the 0.02 value reported by \cite{naranjo2012early}. Density, diameter at age 2 (growth), Volumetric shrinkage, acoustic velocity and stiffness all have significant heritability that breeding for values of these traits is achievable, the values are similar to those reported for other eucalypt species \cite{Hung_2014, Hein_2012, Blackburn_2010, Blackburn_2014, Hamilton_2008}.   p{1cm}  \begin{table}   \begin{tabular}{ p{1cm} p{1cm} p{1cm} }  Property &Heritability &95\% credible intervals \\   Strain & 0.63 &0.28-0.98 \\   Density & 0.54 &0.11-0.97 \\   Diameter & 0.76 &0.42-1.0 \\   Volumetiric Schrinkage & 0.29& 0.13-0.45 \\   Acustic Velocity & 0.97 & 0.60-1.0 \\   Stiffness & 0.82 & 0.48-1.0 \\   \end{tabular}   \caption{Narrow sense heritability of measured wood properties, calculated as per Equation \ref{gse}.}   \end{table}  \begin{table}   \begin{tabular}{ c c c } 

Wood processors pay premiums for timber stable and stiff, while forest growers often prefer to have fast growing trees as to shorten rotation lengths increasing profitability. The preferences are not always aligned, particularly within wood properties. Stiffness, used for grading logs, is positively correlated with growth-strain with a Person correlation coefficient of 0.61, a substantial unfavourable correlation requiring a trade off between the two. While zero growth-strain is desirable to be economically viable to process, some unknown maximum value below which little economic loss is experienced exists. Stiffness is already used for log grades, structural timber in New Zealand requires 8 GPa \cite{nzs3603}. To met these stiffness grades at age two some compromise with the level of growth-strain in the stems is needed. Volumetric shrinkage is moderately negatively correlated with stiffness and strain. Growth and density show only small correlations with all other wood properties.   \begin{table}   \begin{tabular}{ c c c c c c p{3cm} p{3cm} p{3cm} p{3cm} p{3cm} p{3cm}  } & Density & {Volumetric \\ Shrinkage} & Acoustic Velocity & Stiffness & Strain \\   Diameter & 0.15 & -0.10 &-0.02 & 0.02 & 0.12 \\   Density & & 0.12 &-0.03 &0.22 &0.023 \\