Wood of various species of trees have different properties. The different properties with regard to: the anatomical properties of wood, wood physical properties, mechanical properties and chemical properties of wood. Of the difference in the nature of the timber, there are some properties umumyang present in all types of wood. General properties of wood are:
All the trees have a vertical arrangement and properties of radial symmetry.
Wood is composed of cells that have -macam various types, and the composition of their cell walls consist of chemical compounds in the form of cellulose and hemi cellulose (elements of carbohydrates) as well as in the form of lignin (non-carbohydrate).
All the wood is anisotrofik, which show different properties when tested according to the three main directions (longitudinal, tangential and radial). This is due to the structure and orientation of cellulose in cell walls, elongated shape of wood cells, and regulation of the cell to the vertical and horizontal axis on a tree.
Wood is a material that is hygroscopic, which can be lost or increased humidity due to changes in humidity and temperature of the surrounding air.
Wood can be attacked wood destroying living creatures, flammable, especially if the wood is dry.
The physical properties of wood
The physical properties of the wood in question is the density, strength class, grade durable, and depreciation. Mechanical properties or the firmness of wood is one of the important properties that can be used to determine the usefulness of a particular type of wood. Chemical properties in question is a major component of wood is composed of cellulose, hemicellulose, lignin, extractive substances, and ashes. Cellulose is the biggest part contained in the wood, which ranges between 39-55%, and lignin 18-33%, pentosan 21-24%, extractive substances 2-6% and ash 0.2 to 2%.
a) density
The definition of density wood is the ratio of the weight and the volume of timber in a dry state air with the equilibrium moisture content of wood around (for Indonesia on average 14%). Wood specific gravity value is the average value, but to get an idea of the variations in the density of the wood in each type of timber, in between parentheses shall also minimum and maximum values of empirical observations that have been made in the wood.
For example:
Teak wood density is written as follows: 0.67 (0.62 to 0.75)
Durian wood density is written as follows: 0.61 (0.63 to 0.66)
Keruing wood density is written as follows: 0.90 (.84-.96)
Based on its density, there are some terms of timber groups, as follows:
Light, if the density of the wood is smaller than 0.60.
Medium (rather heavy), when the density of between .60-.75
weight, when the density of between 0.75 to 0.90.
It is heavy, when a specific gravity greater than 0.90.
Floating, when the density is less than 1.
Levitating, when the density is equal to 1.
Drowning, when the density is greater than 1. Weight
b) the natural durability of wood
Mean natural durability of wood is wood resistance against wood destroying elements from outside such as fungi, termites, powder, marine worms and other creatures, as measured by annual time period. TSB wood durability due to the substance inside the timber (extractive substances).
c) The color of the wood
There are a variety of colors of wood, such as yellow, whitish, light brown, dark brown, blackish, kemerahmerahan and others. This is caused by substances in the wood filler color different. The color of a wood species can be affected by several factors including: a place in the trunk, trees, and humidity. For guidance on the introduction of timber in use is the color of the wooden porch.
d) Hygroscopic
Wood has hygroscopic properties, namely dpat absorb or release water or moisture. Wood moisture is very strongly influenced by humidity and temperature of the air at one time. The more humid air around it will be the higher the humidity of wood to achieve a balance with its environment. The moisture content in the wood of this kind is called the equilibrium moisture content (EMC = Equilibrium Moiture Content).
e) Texture
Texture is the relative size of the cells of the wood. Cell intent wood is wood fibers. So we can say that the texture is the relative size of the wood fibers. Based on the texture, the type of wood can be divided into three categories, namely:
a. finely textured wood, such as wood Giam, lara, Kulim and others.
b. Wood textured, such as teak, sonokling, and others.
c. Rough textured wood, for example kempas, meranti, and others.
f) Fiber
Relating to the nature of wood fiber, which indicates the general direction of the wood cells in the wood to the axis of the tree trunk. Direction of the fiber can be determined by the direction of grooves on the surface of the wood. Wood said fibrous fine, if the direction of the cells of the wood parallel to the axis of the rod. If the direction of the cells deviate or an angle to the long axis of the rod, then it is said to be along oblique wood. Oblique fibers can be divided into four kinds, namely fiber blends, corrugated fiber, twisted fiber, and diagonal.
g) Fibre chime
If batng timber consists of layers of alternating, deviate to the left and to the right of the axis of the rod, said fibrous chime. Examples are wood Kulim, renghas and lime.
h) fiber choppy
Wavy fibers are fibers kayuyangmembentuk choppy picture. Examples are renghas wood and merbau.
i) fibers twisted
Twisted fibers are wood fibers that form a picture twisted (torsion), as if the wood is twisted around the stem axis. Examples are bintangur wood, limestone and resin.
j) Fiber diagonal
Diagonal fiber is a fiber found on pieces of wood or board, sawed such that the edges are not parallel to the direction of the axis, but at an angle to the axis.
k) Violence
In general, there is a direct relationship between the hardness of wood and timber weight. Hard wood that also includes heavy timber. Instead of light wood is softwood. Based on the hardness, the types of wood can be classified as follows.
The wood is very hard, for example, chaos and Giam
Hardwoods, for example kulim and Pilang
Wood moderate hardness, such as mahogany and meranti
Softwoods, such as pine and balsa
How to set the hardness of wood is to cut the timber with the transverse direction and take notes or assess the impression resistance TSB wood when cutting, and cutting the resulting kilapnya field.