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Unit 4Unit 4Lumber ManufactureLumber Manufacture

Sawmill Operations • Sawing Methods • Seasoning Methods • Planing and Grading • Lumber

Defects • Wood Protective Treatment

Sawmill Operations • Sawing Methods • Seasoning Methods • Planing and Grading • Lumber

Defects • Wood Protective Treatment

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Trees are cut using a feller buncher that grasps a tree as it is sawn off at the base. Trees sustain less damage when felled in this manner.

Trees are cut using a feller buncher that grasps a tree as it is sawn off at the base. Trees sustain less damage when felled in this manner.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Log loaders stack logs on a truck for transport to a sawmill.Log loaders stack logs on a truck for transport to a sawmill.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

A log can be cut into many shapes and sizes of lumber.

A log can be cut into many shapes and sizes of lumber.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Logs are conveyed into the sawmill from a log merchandising deck.Logs are conveyed into the sawmill from a log merchandising deck.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

The logs pass through a debarker to remove bark and dirt, which may dull saw blades used in subsequent operations.

The logs pass through a debarker to remove bark and dirt, which may dull saw blades used in subsequent operations.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Boards are fed into the trimmer by conveyor belts. A trimmer consists of a series of saw blades that remove defects and cut the boards to standard lengths.

Boards are fed into the trimmer by conveyor belts. A trimmer consists of a series of saw blades that remove defects and cut the boards to standard lengths.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Lumber sawing methods include plainsawing, quartersawing, and rift sawing.Lumber sawing methods include plainsawing, quartersawing, and rift sawing.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Lumber is stacked on tram cars and transported into a kiln for seasoning. Note the stickers placed between rows of lumber to allow for complete circulation of air.

Lumber is stacked on tram cars and transported into a kiln for seasoning. Note the stickers placed between rows of lumber to allow for complete circulation of air.

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Lumber is graded and sorted according to thickness, width, and length as it moves along a conveyor belt.Lumber is graded and sorted according to thickness, width, and length as it moves along a conveyor belt.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Knots are found in most grades of lumber. A small number of sound knots will not significantly affect the lumber strength.

Knots are found in most grades of lumber. A small number of sound knots will not significantly affect the lumber strength.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Splits and wanes are among the lumber defects that occur from natural causes.Splits and wanes are among the lumber defects that occur from natural causes.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Warpage can occur during the evaporation of water from wood cells.

Warpage can occur during the evaporation of water from wood cells.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Dry rot is the breakdown of wood caused by a wood‑destroying fungus.Dry rot is the breakdown of wood caused by a wood‑destroying fungus.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Levels of wood deterioration vary depending on humidity levels and temperature.

Levels of wood deterioration vary depending on humidity levels and temperature.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Waterborne preservatives are used for residential, commercial, marine, agricultural, recreational, and industrial construction applications.

Waterborne preservatives are used for residential, commercial, marine, agricultural, recreational, and industrial construction applications.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Untreated lumber is placed in large cylinders and impregnated with preservative.

Untreated lumber is placed in large cylinders and impregnated with preservative.

Unit 4 — Lumber ManufactureUnit 4 — Lumber Manufacture

Grade marks for pressure-treated lumber include information about the exposure conditions for proper use of the lumber, and also indicate the type of preservative used on the lumber.

Grade marks for pressure-treated lumber include information about the exposure conditions for proper use of the lumber, and also indicate the type of preservative used on the lumber.