Task Today.
Explain with a graphic the different parts of the tree? The tree has three main parts: leaves, branches, and roots. The upper part of the tree with the branches is called the crown. The roots are the part of the tree that grows underground. Leaves are the part of the crown of a tree.
Show and explain the different parts of the cross-section of a trunk?
Sapwood: Sapwood is the new wood under the Cambium layer. It is often lighter in color than true wood or heartwood and it conducts water and mineral salts from the root system of the tree to the leaves.
Dead bark: Dead bark or outer bark is a layer of dead tissue that is a protection for the trunk and branches. It also helps to reduce water loss from the living cells of the tree. Some trees shed their dead bark each year while on others dead bark is reduced only by the weathering processes.
Live Bark: Live bark is a layer of living tissue under the dead bark. Food materials produced by the leaves are conducted through the live bark to the branches, trunk, and roots of the tree.
Cambium Layer: The Cambium layer is the layer of thin cells, invisible to the naked eye positioned inside the live bark. This layer of cells facilitates all growth in the thickness of the tree trunk. The Cambium grows wood cells on the inside and lives barks cells on the outside.
Heartwood: Heartwood is made up of cells that are actually dead. It provides the strength necessary to support the tree. Heartwood is formed by the blockage of the channels which conduct food materials. Blockage occurs as stored food materials are converted into tennis, resins, and other related substances. Heartwood is much more durable than sapwood.
The Pith: The pith is at the center of the tree and is a soft, pulpy zone that is usually about one centimeter in diameter.
Describe/Explain how trees become timber?
Felling of trees. Conversion of logs into boards. Drying of green boards into dry timber, ready for use. The first stage of timber processing involves tree felling and only mature trees are selected to allow young ones to grow. Stage two involves stacking tree trunks/logs in a store or clearing till they are required at the sawmill. This stage is mainly to allow the logs tree completely from moisture or water.
Describe explain the different types of cuts? (e.g Quartersawn)
Quartersawn lumber is defined as wood where the annular growth rings intersect the face of the board at a 60 to 90-degree angle. When cutting this lumber at the sawmill, each log is sawed at a radial angle into four quarters, hence the name. Dramatic flecking is also present in red oak and white oak.
A Plain saw a saw in which the blade has teeth with no pitch. Plain sawn lumber is produced by making the first cut on a tangent to the circumference of the log. Each additional cut is then made parallel to the one before. This method produces the widest possible boards with the least amount of log waste.
Rift sawn lumber is typically narrow with a very straight grain pattern on the face of the board. Rift sawn lumber is usually used with oak to avoid the flecks that are common in the species. The annular rings or a rift sawn board are about 30-60 degrees to the face of the board, but 45 degrees is the most optimum.
Give an example of defects in timber Knot
Knots are imperfections from branches that cause living wood grain to grow around them.
Give examples of timber used in NZ
Rimu (red pine)
Matai (black pine)
Baltic pine-Baltic Pine is known to be relatively light and is widely used in construction, this timber an ideal choice for window frames, flooring, cladding, furniture and general carpentry. Baltic Pine trees have a variety of uses and it is an ideal plantation timber.
Redwood- A redwood can't grow to be the tallest tree on earth alone. Redwoods create the strength to withstand powerful winds and floods by extending their roots more than 50 feet from the trunk and living in groves where their roots can intertwine.
Kauri- a tall timber tree of New Zealand having fine white straight-grained wood.
