Sonokeling Wood, Characteristics and Applications in the Wood Industry

Sonokeling (Dalbergia latifolia) and sono kembang (Pterocarpus indicus) are often called the Makasar ebony or Indian rosewood. Sonokeling is the Javanese name of the wood that is also used in the Indonesian woodworking business terminology. Sonokeling wood is one of the tropical hardwood species known for its unique color and grain patterns. This wood is not much used as the mahogany, teak, or other popular wood, but it is known as a high-value wood. It is widely used for various high-end wood products, particularly applications that emphasize the natural beauty of wood, such as furniture, decorative panels, flooring, handicrafts, and interior elements. The combination of dark colors and distinctive grain patterns gives sonokeling wood an elegant appearance that sets it apart from many other wood species.

Sonokeling plantation

Sonokeling is commonly known by its scientific name, Dalbergia latifolia. In international trade, this species is often referred to as Indian Rosewood or East Indian Rosewood. Species belonging to the Dalbergia genus are widely distributed throughout tropical and subtropical regions, including Asia, Africa, Madagascar, and South America. Sonokeling naturally occurs in India and was later introduced and cultivated in Indonesia during the colonial period. Dry and rocky soils are considered suitable environments for its growth. The tree is found a lot in the Indian subcontinent, from the foothills of the Himalayas to the southern tip of the peninsula, especially in the dry areas of Karnataka, Kerala, and Tamil Nadu. This plant lives well in areas with rainfall of 750-5000 mm per year. He can live on a variety of soil types, but he lives best in deep soils and moist climates with good drainage. 

In Indonesia, the sonokeling trees grow wildly on the slopes of many mountains in Central Java and East Java in the area with an altitude of 600 m or above sea level. The tree is also planted in intercropping systems with a variety of horticultural trees, such as rice fields, maize, cassava, or beans. Some people also plant this tree as a constituent in agroforestry, mixed with fruitwood such as mango, jackfruit, soursop, guava, etc. Sonokeling has long been recognized as a premium wood with high aesthetic value. Sonokeling trees are often planted on mountain slopes as part of reforestation and soil conservation efforts. They are also commonly planted among teak forests as an additional tree species.

Characteristics of Sonokeling wood

The sapwood of the sonokeling has a white or light brown color and a vague pattern of grain and is mostly rejected as waste. The heartwood of sonokeling has a very distinctive color, ranging from purplish brown and dark brown to almost black. The wood features an attractive grain pattern characterized by contrasting lines of lighter brown and dark brown to nearly black tones. Color and grain variations can differ depending on the age of the tree, growing conditions, and the part of the trunk being used.

The grain of sonokeling is generally straight to slightly wavy and can produce a highly attractive look by cut and arrangement techniques. When sliced into veneer, sonokeling can produce a wide variety of grain patterns that can be used to create decorative surfaces and unique furniture designs. The wood has a smooth surface with small pores and fine grain. It can produce a smooth surface without requiring excessive coating material.

Sonokeling is also known as a hard, dense, and heavy wood. These characteristics are suitable for furniture products even with special design. Its strength can accommodate building the components that require high mechanical strength. This wood is also available to be used for construction, such as doors, walls, and flooring.

Advantages of Sonokeling Wood

• Exotic color and grain

One of the main advantages of sonokeling wood is its natural beauty of color and grain pattern. The combination of dark brown, reddish brown, purple, and dark streaks creates an exclusive appearance in furniture and interior products. Its natural color and look are already visually strong and potentially give the attractive look when used in the right design and model.

Its unique grain pattern is another important feature. In certain sections, the grain can form wavy patterns or unique combinations of colors. The natural beauty of this wood makes sonokeling a premium material with high aesthetic value. It is often used as a major decorative element in high-end wood products.

In interior decoration products, sonokeling can be used as a focal point or as an accent that draws attention. Its distinctive appearance allows even a relatively simple furniture design to look elegant and sophisticated.

• Hard and strong

Sonokeling is classified as a hardwood and can therefore be used for furniture components that require strength and resistance to everyday use. It is suitable for making legs, frames, panels, table tops, and other structural components. Its strength and hardness also make it suitable for architectural and interior applications where both durability and appearance are important, including stairs, doors, flooring, and decking.

Disadvantages and challenges

Although sonokeling offers many advantages, it also presents several challenges during processing.

• Need careful processing

Sonokeling is hard, dense, and heavy, so cutting, planing, shaping, and sanding require appropriate techniques and tools. The wood also contains natural extractives and oils that can interfere with machining, gluing, and finishing processes. In furniture manufacturing and the woodworking industry, the selection of cutting tools, machine condition, feed speed, and sanding techniques should be adjusted to suit the characteristics of the material. 

The wood can also require a relatively long drying period. Kiln drying or air drying should be carefully controlled because drying too quickly can cause quality problems such as dimensional changes, cracking, and undesirable color changes, which may reduce the value and quality of the material.

• Expensive and less available

Sonokeling trees require a relatively long growing period before harvesting, while the number of plantations is relatively limited. The wood is not available abundantly as Sengon, Mahongany, Mende, pine, and other common wood species. The Sonokeling wood is considered expensive and rarely available in the woodworking industry. Sonokeling wood and veneer are more used for the special and high-price product instead of the solid wood. 

Applications of Sonokeling wood

Sonokeling wood can be used for a wide range of products that emphasize strength, durability, and aesthetic value. Its distinctive color and grain patterns make it suitable for dining tables, coffee tables, chairs, cabinets, doors, and many other types of furniture. Sonokeling can also be used as an accent material in furniture. For example, in a simple table design, sonokeling can be used for the tabletop so that its grain pattern and natural color become the main focal point. With the right design and finishing system, the natural character of sonokeling can give a product a luxurious and exclusive appearance.

Simple and clean designs can actually provide the best opportunity for the natural beauty of sonokeling to stand out. Combining sonokeling with other materials such as metal, glass, or neutral-colored finishes can also create furniture with a modern and elegant appearance. 

Instead of wood furniture, sonokeling can also be used for decorative wall panels, flooring, interior elements, veneer, handicrafts, accessories, and decorative objects. Its natural beauty and distinctive color make it suitable for a variety of interior design styles.

Tips for using Sonokeling wood

• Proper drying and processing

The wood should be properly dried before it is cut, machined, and shaped into the required components. The drying process should be carefully controlled to maintain the dimensional stability and overall quality of the wood.

Machining, sanding, and gluing should also be carried out using techniques appropriate for this type of hardwood. Fortunately, modern woodworking technology has developed significantly, making it easier to process hard and dense wood efficiently and accurately.

• Right design and proportion

Although sonokeling has a high level of natural beauty, it should still be used in the right proportion. Its dominant dark brown to almost black color can create a strong visual impression. Using too much sonokeling throughout an interior space may make the room feel visually heavy or overly dark. For applications such as doors and flooring, it is often better to combine sonokeling with lighter colors and materials to create balance and prevent the interior from feeling too dark or overwhelming.

• Right finishing color and look

To maximize its natural beauty, sonokeling should be finished properly. A natural finish with a light stain—or even no stain at all—is often one of the best choices for this wood. Applying a heavy or opaque stain can hide the natural grain and reduce the visual character of the wood.

A clean finish with a close-pore appearance and a sufficiently thick film build can create an elegant and luxurious appearance. An antique finishing system using a small amount of glaze and controlled distressing can also produce a distinctive classic or antique appearance.

Solid-color finishes are generally not the good choice because they will cover and kill the beauty of the wood. The natural oils and extractives in the wood may also interfere with the solid color of the paint applied on it. 

Various types of wood coatings can be used on sonokeling, depending on the desired appearance and performance. NC (nitrocellulose) coatings can be a good choice when the objective is to emphasize the natural color and grain of the wood. PU (polyurethane) coatings are suitable for close-pore finishing systems that require a thicker and more durable film. Other coating systems can also be selected depending on the required quality, appearance, durability, and production process.

• Anti-insect chemical treatment

Although sonokeling is relatively resistant to insect attack compared with some other wood species such as mahogany, mango wood, and certain fruit woods, it can still be exposed to the risk of insect infestation. For this reason, appropriate preventive insect treatment is recommended, particularly when the wood will be used in furniture, architectural components, or other products that are expected to have a long service life.