deletions | additions       diff --git a/intro.tex b/intro.tex  index f643511..e15effe 100644  --- a/intro.tex  +++ b/intro.tex 
...
\section{Introduction}  The stiffness and strength of timber is important to industries which rely on it as a building material. As a consequence of high variability in these properties when trees are milled, timber is graded. There has been interest and research in breeding trees which reliably produce this higher value timber --ref--.  Trees are subjected to multiple environmental mechanical loads and adapt the mechanical properties of their stems to an environment changing over time. Wind is one of the most important (Timell, 1986a). 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 (Ancelin et al., 2004; Peltola et al., 1999; Mayer et al., 1989; Gardiner et al., 2000; Dunham and Cameron, 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 (Timell, 1986a).  While MFA controls 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. --introduce TRP here ---