If you’re curious about identifying Koa wood, this guide is for you.

Koa can be identified by examining three main attributes: color, grain, and origin. Generally, Koa exhibits a reddish-gold to dark-brown hue. Its interlocking grain often produces a highly curly or figured appearance. Most importantly, its origin is exclusively Hawaii.

However, Koa’s appearance varies greatly, which makes identification challenging unless you have significant experience with the wood. Below, I’ll share insights from my years of growing, milling, and working with Koa.

Where Does the Wood Come From?

Koa is endemic to Hawaii and does not grow anywhere else. While terms like “Brazilian Koa” or “Australian Koa” exist, these woods are not Acacia Koa. Koa requires specific growing conditions—including temperature, elevation, soil, and rainfall—that only certain areas of Hawaii provide. Thus, any wood not originating from Hawaii cannot be Koa.

What Color is Koa Wood?

Koa’s color ranges from reddish-gold to dark brown, often with hints of yellow or blonde. The color can vary based on genetics, age, and growing location.

• Young Trees: Wood from younger trees is lighter due to a higher proportion of sapwood—the outer, active tissue of the tree. Younger Koa, often less than 30 years old, lacks a significant amount of heartwood, making it harder to identify.
• Older Trees: Older trees have more developed heartwood, which is denser and darker. These characteristics make identification easier and the wood more desirable.

Koa from the Big Island tends to be darker and richer in color, possibly due to the island’s younger, more acidic volcanic soil. Genetics also play a role, as trees from different islands show distinct variations.

What Does Koa Wood Grain Look Like?

Koa wood grain is highly distinctive, and there are three common types:

• Straight Grain: The grain runs in one direction with minimal waves or curls, appearing mostly parallel.
• Curly Grain: Compression in the wood creates alternating stripes perpendicular to the surface, resulting in a three-dimensional illusion known as chatoyancy. This is Koa’s most sought-after feature.
• Figured Grain: Similar to curly grain but with uneven twists and unpredictable turns. Figured grain doesn’t always run perpendicular and varies greatly within the same tree.

Curly or figured grain is often found in older trees that have endured environmental stressors, such as storms or heavy branch weight. These stressors encourage unique grain patterns. Elevation also plays a role: higher elevations produce slower-growing trees with more pronounced grain features. Milling techniques, like quarter-sawing, can further enhance these patterns.

Is Koa Wood Heavy?

Koa is a moderately heavy hardwood with a specific gravity of 0.63. For comparison, walnut has a specific gravity of 0.55, and ironwood ranges from 0.70 to 0.99. Koa’s weight can vary depending on factors like density and age.

What Does Koa Smell Like?

Koa has a sweet, woodsy fragrance, most noticeable during the milling or drying process. However, the scent is subtle and not easily detectable unless working with large amounts of the wood.

How to Be Sure It’s Koa

If the wood originates from Hawaii, matches Koa’s characteristic color range, and exhibits curl or figuring, it may indeed be Koa. However, Koa’s features—while pronounced—are not exclusive. For instance, maple can have similar figuring, and walnut shares some color traits. Identifying Koa conclusively is difficult without handling the wood directly, and even then, absolute certainty can be elusive.

Conclusion

Identifying Koa wood requires a trained eye and careful consideration of its origin, color, and grain. While it’s a challenging process, the unique beauty and variability of Koa make it worth the effort. If you’re uncertain, consulting with an expert can provide valuable insight into whether your wood is truly Koa.