Teak Wood Harvest — How to Fell and Process Teak Wood from Java

Teak wood (Tectona grandis) belongs to the Lamiaceae family, originating from Southeast Asia. Teak wood can reach heights of 30-40 meters when mature. Its leaves are large (30-60 cm long), resembling tobacco leaves, and fall during the dry season (teak is a deciduous tree). The flowers are small and white, appearing during the rainy season. The bark is rough and ranges in color from gray to brown. Teak wood has two main layers: heartwood which is golden brown in color and sapwood which is lighter in color. The heartwood contains natural tectoquinone oil which makes the wood resistant to termites and water resistant.

Teak wood that is best for furniture must be 40-80 years old. At this age the heartwood has grown perfectly and the proportion of heartwood is greater than sapwood. Signs of trees that are ready to be felled: stem diameter at breast height (DBH, diameter at breast height) minimum 30-40 cm, tree bark is rough and cracked, and the tree is no longer growing tall (has reached maximum height). Perhutani uses a rotation cycle (rotation cycle) of 60-80 years. Younger trees can be felled for building timber, but the quality is not as good as old wood.

Girdling (ring-barking) is the process of cutting the bark around the entire trunk with a width of 10-15 cm, removing the cambium layer. This process is carried out 1-2 years before felling. The purpose is for the wood to gradually lose water and sap, becoming lighter and drier when felled. Girdled wood is easier to dry and cracks less during the drying process. Girdling is done in the dry season when sap flow is at its lowest. Cut the bark carefully using an axe or machete — do not cut into the wood itself, only remove the bark and cambium.

Felling teak is best done in the dry season (June-September in Java) when the water content in the wood is at its lowest. During the dry season, teak trees have shed their leaves and sap flow has stopped. Wood felled in the dry season dries faster, cracks less, and is more resistant to termites than wood felled during the rainy season. Do not fell during heavy rain or when the ground is wet — there is danger of slipping and the wood gets dirty easily.

Logs or boards are arranged by inserting stickers (wooden separators) between each layer. Stickers are usually sized 2x2 cm or 3x3 cm, made from dry wood that has been treated with anti-fungal. The distance between stickers is approximately 60-90 cm. Stickers must be arranged straight vertically from bottom to top so that the weight is evenly distributed and does not bend. Natural drying (air drying) of teak wood requires 6-12 months depending on the thickness of the wood and weather conditions. The target moisture content is 12-15% for furniture. Each cubic meter of dry teak wood weighs approximately 640-720 kilograms.