Takamine Wood | What is Obi Cedar (Obisugi)?

About Obi Cedar (Obisugi)

Obi cedar (Obisugi), grown in the rich forests of Nichinan, Miyazaki, Japan,
is a historic type of Japanese cedar known for its resin-rich wood and resistance to moisture and decay.
It was once prized as a shipbuilding material, and today it is widely used in housing and many other buildings, including structural and interior applications.

A historic cedar used since the Obi Domain era

Planting of Obi cedar began in the Edo period under the Obi Domain, originally for ship timber, giving it a history of about 400 years.
Its high oil and resin content helps it resist decay even in the humid climate of southern Kyushu, leading to the saying: “If you build a ship, use Obi cedar.”

Today, Obi cedar is highly regarded as structural and interior building material. The flexibility and strength nurtured by a warm climate contribute to safe and comfortable living spaces.

Why Obi Cedar is Chosen

Obi cedar offers strength, flexibility, and the comfort unique to wood.
At Takamine Wood, we maintain a production system that enables stable quality while making the most of these characteristics.

1. High durability and decay resistance

Obi cedar is rich in resin, making it resistant to decay and highly water-resistant.
Its heartwood (the reddish core) is also known for termite resistance, making it suitable for long-lasting homes.

Comparative tests against termites

Obi cedar has long been considered termite-resistant

Obi cedar (Obisugi) has historically been known as a wood that termites are less likely to attack. Certain components contained in the wood are considered to have properties that deter termites.

Heartwood contains termite-killing active components

In experiments conducted by Miyazaki University and the Toyo Termite Research Institute, tests using heartwood wood flour of Obi cedar reported that 30 Formosan subterranean termites were all dead by day 11. These results indicate that Obi cedar heartwood contains components with termiticidal activity.

High durability confirmed in comparisons with other wood

In a soil burial test conducted by Miyazaki Prefecture’s wood-related association, Obi cedar boxed-heart posts (12 cm square) were compared with whitewood laminated posts (12 cm square) after being buried for about 10 months.
Obi cedar—both green and dried—showed only minor damage, while the whitewood suffered termite damage severe enough to crumble at the surface.

Field exposure test in a pine forest (Field Exposure Test)
After 3 months: Field exposure test (Field Exposure Test)
Soil burial test in a pine forest (Soil Burial Test / Ground Burial Test)
After 2 years: Soil burial test (Soil Burial Test / Ground Burial Test)

About “aerial roots” often seen in Obi cedar

On the surface of cedar trunks, you may sometimes see small whisker-like protrusions or tiny wart-like bumps. These are called “aerial roots.”
When sawn, they can appear as small dark dots on the surface of the lumber. Unlike ordinary branches, they do not extend deeply into the trunk and are typically enveloped into the trunk over several years.

Therefore, they have little to no impact on strength performance, and the wood can be used with confidence as structural material. Aerial roots tend to appear around 1 meter above the ground and are especially common in Obi cedar.
Conversely, if aerial roots are visible on the surface of a product, it is sometimes said that the species is likely to be Obi cedar.

Example of aerial roots seen in Obi cedar

2. Flexible and resistant to breaking

Grown in the warm climate of southern Kyushu, its grain does not become overly dense, giving it toughness and good bending performance.
This ease of handling as structural material is valued in many homes.

3. Humidity control and thermal comfort

Thanks to its wood structure containing air, it naturally absorbs and releases moisture to help maintain indoor comfort.
It feels fresh in summer and warm in winter, contributing to a pleasant living space year-round.

4. Stable supply and quality control

Miyazaki is Japan’s leading region for cedar log production.
With in-house sawmilling, drying, and processing facilities, Takamine Wood maintains a system that enables stable quality and nationwide shipments.

Gentle comfort and peace of mind for everyday living

Obi cedar provides not only structural strength, but also a natural softness and comfort in living spaces.
Its gentle feel underfoot and calm appearance—reducing harsh light reflection—bring a sense of warmth to the home.

Its humidity-regulating properties also help maintain comfort in Japan’s climate with distinct seasonal changes, creating a friendly environment for families to spend time together.

The Power of Wood

Wood—including Obi cedar—has many gentle qualities that make everyday life more comfortable.

An image representing the benefits of wood

Gentle on the eyes

Fine natural texture on a wood surface softens light and reduces glare. It can also help reduce harmful UV exposure.

Natural humidity regulation

Wood absorbs and releases moisture, naturally helping to balance indoor humidity. This can reduce condensation and maintain a comfortable air environment.

Thermal insulation and a comfortable touch

Tiny air pockets within wood make it less conductive of heat, creating a gentle temperature feel that is not overly cold or hot to the touch.

Softness and shock absorption

Wood’s moderate elasticity helps cushion impacts from falls, and tends to reduce strain on legs and lower back when walking for long periods.

Typical Uses of Obi Cedar

Thanks to its light weight and workability, Obi cedar is used in a wide range of applications.

Structural members (posts & beams)

With a balance of flexibility and strength, it is used for structural members such as posts and beams in homes.

Flooring

Its gentle feel underfoot and warm appearance make it popular for living areas and rooms.

Wall/ceiling paneling

Lightweight and easy to handle, it is widely used for ceilings and walls as well.

Decking & exterior materials

Taking advantage of its durability, it can be used for decking and exterior applications.

Protecting forests and connecting timber to the future

To protect Miyazaki’s rich forests, it is essential to harvest responsibly, use timber, and replant.
With an integrated system for sawmilling, drying, and processing, Takamine Wood sustainably utilizes local forest resources while supplying high-quality Obi cedar with stable quality.

Trees grown in the forest support homes and protect the lives of the next generation.
As part of this cycle, we carefully bring out the value of Obi cedar.