Nicholas Davies edited intro.tex  over 7 years ago

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\section{Introduction}  Trees, unlike animals have a fixed physical location and throughout their life experience ontogenetic and environmental changes. During development changes in size, shape and wood properties occur for both environmental and ontogenetic reasons. These changes are observed in trends of many physical and chemical wood properties having evolutionary function in mechanical stability and a host of other necessary requirements for survival (see --ref-- \citet{meinzer_frederick_2011}  for a review). The Typical Radial Pattern (TRP) of Micro-Fibril Angle (MFA) and density has been argued to exist to provide superior mechanical stability by some --ref-- while others have suggested the pattern exists for hydraulic function --ref--. The aim here is to investigate alternative, unobserved radial patterns of MFA and density with respect to mechanical stability utilizing existing wood property data for green core- and outer-wood (sourced from \citet{Davies_2016}) to form mathematical mechanical system models which are sloved using Finite Element Modeling as an analytical tool. While MFA contributes to the stiffness of the cell wall, basic density measures the amount of cell wall in the tissue. Therefore overall mechanical wood properties rely on both features. Wood properties within 'normal' stems tend to follow TRP \citep{meinzer_frederick_2011}. MFA reduces while density increases from the pith to the periphery of the stem. Note that this is not universal and some species and individuals do not necessarily follow the pattern completely.