Jul 2, 2011

What is Box-Heart Timber?

Timber Cross Section

Before we talk further about Box-Heart timber, lets take a look at the cross section of a log, and understand some terminology used in timber industry, please take a look at the timber on the left.

Sap Wood: Is the outermost layer of a logs, and it is the living portion of a tree. In term of biological function, this is the part where food (minerals & nutrient) and water is being transported from the root to the rest of the tree, and to a lesser extent, where energy reserves (food) are stored. Sapwood is the most nutrient-rich section, thus wood from this portion get rotten/decay more easily.

True Wood: As the older sapwood cells age and die, they become True Wood, or more commonly known as heartwood. These cells cease to transport water or store energy reserves; and hence it has higher resistance against rotting and decaying compare to sapwood.

Heart: Is usually located at the center of the timber (it can be off-centered sometimes), which is relatively softer and more brittle compare to true wood and sap wood. Hence, it is lower in strength especially in taking tension load.

Box-Heart Timber, simply means timber that includes the heart; being boxed together, as picture shown below. Box-Heart timber is mainly used in application where compression load is more of a concern than tension loading. Where aesthetic and tension loading are a concern, box-heart timber is not recommended; because box-heart timber will easily crack from center.

Picture below shows the production method for box-heart timber and true-wood timber. For the same size, one can notice that log that is used to cut box-heart timber is way much smaller compared to logs that is used to cut true-wood timber.