deletions | additions       diff --git a/intro.tex b/intro.tex  index a9e2a12..a9bae19 100644  --- a/intro.tex  +++ b/intro.tex 
...
\section{Introduction}  Trees are subjected to multiple Trees, unlike animals have a fixed physical location and throughout their life experience ontogenetic and  environmental mechanical loads changes. During development changes in size, shape  and adapt the mechanical wood  properties occur for both environmental and ontogenetic reasons. These changes are observed in trends  of their stems to an environment changing over time. Wind is one of the most important \citep{timell_compression_1986-2}. Wind loading can cause mechanical failure making the tree worthless many physical and chemical wood properties having evolutionary function  in mechanical stability and  a commercial sense. A substantial amount host  of research on predicting wind throw and wind damage risk other necessary requirements  for commercial species survival. The Typical Radial Pattern (TRP) of Micro-Fibril Angle (MFA) and density  has been conducted \citep{ancelin_development_2004, peltola_mechanistic_1999, mayer_windthrow_1989, gardiner_comparison_2000, dunham_crown_2000}. These models do not investigate the structural failure within the tree, but attempt argued to exist  to identify how likely failure provide superior mechanical stability by some --ref-- while others have suggested the pattern exists for hydraulic function --ref--. The aim here  is to occur in a particular environment. Wind also has less obvious effects. Continued wind loadings from a prevailing direction can cause reaction investigate alternative, unobserved radial patterns of MFA and density with respect to mechanical stability utilizing existing  wood production in order property data  to compensate for this loading \citep{timell_compression_1986-2}. form mathematical mechanical system models which are sloved using Finite Element Modeling as an analytical tool.  While MicroFibril Angle (MFA) 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 what is known as the Typical Radial Pattern (TRP) 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. Wind is one of the most important mechanical loads \citep{timell_compression_1986-2}. Wind loading can cause mechanical failure making the tree worthless in a commercial sense. A substantial amount of research on predicting wind throw and wind damage risk for commercial species has been conducted \citep{ancelin_development_2004, peltola_mechanistic_1999, mayer_windthrow_1989, gardiner_comparison_2000, dunham_crown_2000}. These models do not investigate the structural failure within the tree, but attempt to identify how likely failure is to occur in a particular environment. Wind also has less obvious effects. Continued wind loadings from a prevailing direction can cause reaction wood production in order to compensate for this loading \citep{timell_compression_1986-2}.  Over the last century or so there have been a number of suggested explanations for why trees grow with the observed TRP. The mechanical hypothesis which is investigated in this study, asserts that the TRP is a result of the tree needing to respond to different mechanical loadings from its environment as it grows. For a seedling, being highly flexible could be important in order to bend out of the path of animals and reduce wind and snow loads. However when the tree grows and a significant size is reached along with a large canopy greater stiffness could be an advantage in outerwood as bending becomes difficult due to the stem diameter. Note that there are other hypotheses, for a good review see \citet{meinzer_frederick_2011}. The purpose of this paper is to investigate the effect of the TRP of MFA and density on the ability to withstand wind loading.