| Term |
Definition |
| Green | Unseasoned timber. |
| Glue laminated timber (Glulam, GLT) | Engineered product made from layered strips of structural timber, where all pieces have the grain running in the same direction. Not to be confused with ‘cross laminated timber’. |
| Glut | Packing material, often 70 x 50, used to provide space for forklift tynes or slings to be inserted under the pack. |
| Grain | Direction and arrangement of the wood fibres in a piece. |
| Green density | Mass (weight) of a timber species expressed in kilograms per cubic metre when the timber is green (unseasoned). |
| Growth rings | Rings formed by the alternation of ‘earlywood’ and ‘latewood’ growth in a tree, marking the seasonal cycles of growth. |
| Gum | Natural substance, also called kino, produced in hardwood trees as a result of fire or mechanical damage. (Note that ‘resin’ performs the same function in softwoods.) |
| Gum pocket | Cavity in the wood tissue that contains gum. |
| Gum vein | Deposit of gum between growth rings. ‘Tight gum veins’ have bridging fibres across the gum, which help to hold the wood tissue together on either side of the vein. ‘Loose gum veins’ have a complete separation of fibres through the vein. |
| Hardwood | Timber coming from ‘angiosperm’ trees, where the seeds are contained inside a fruit or flower, and the wood structure is characterised by ‘pores’ (also called ‘vessels’). |
| Heart | Wood that includes the pith or is near the pith. For plantation softwoods, it includes any material within a 50 mm radius of the pith. Also referred to as ‘corewood’. |
| Heart shake | Shake that extends from the pith of a tree (see ‘shake’). Sometimes referred to as a ‘star shake’ when adjoining shakes form the shape of a star in the end section of the piece. |
| Heartwood | Wood containing dead cells that make up the centre part of the tree, filled with waste products such as tannins, resins and gums. |
| Hit and miss | Machining imperfection where the dressed surface has skipped areas that the cutters have missed. |
| Hole | Hole extending partway or right through a piece – including cone hole, flight hole (from an emerging insect), grub hole, borer hole, knot hole and pinhole. |
| Honeycombing | Drying defect resulting in internal checking that has a lens-like shape. |