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Natural Features
Natural features come from branches and irregularities in the tree, and affect the finished appearance of timber. They include things like knots, gum veins, checks and pin holes. If there is a desire to limit or control natural features, then the appropriate garde of timber should eb specified. For hardwoods this includes options such as: select, medium feature and high feature grades – as defined by AS 2796.2. For Cypress this includes Grade 1 and 2 – as defined in AS 1810. These grades objectively define the number, type and spacing of knots and imperfections. As an example, variation in grades for hardwoods are shown in Figure 9 and summarised below:

Select Grade – (SEL)

• permissible features: small holes and small tight knots,
  
• not permitted: enclosed termite galleries, shakes, splits, decay, loose knots, gum pocket, narrow gum veins, want, wane or mechanical damage and non natural stains or sticker marks.

Medium feature Grade – Standard (MF):

• permissible features: tight knots, small holes, tight and loose gum veins, limited gum pocket and checks,
  
• not permitted: enclosed termite galleries, shakes, splits, decay, want, wane or mechanical damage and non natural stains or sticker marks,

High Feature Grade – (HF)

• permissible features: knots, holes, tight and loose gum veins, limited gum pocket and checks,
  
• not permitted: enclosed termite galleries, shakes, splits, decay, want, wane or mechanical damage and non natural stains or sticker marks,

Before selecting a grade it is useful to compare the relative features expected in each species. Some are more prone to knots, holes, gum veins and insect attack, than others. This can be explored by referring to the Species Guide referenced in Section 5. Before selecting a grade it is useful to compare the relative features expected in each species. Some are more prone to knots, holes, gum veins and insect attack, than others .This can be explored by referring to the Species Guide referenced in Section 5.

Figure 9: Various appearance grades in hardwood