When twigs break off a kiawe, the thorns dry to hard, sharp spikes.

Kiawe thorns growing on the tree.

A stand of kiawe trees bordering a trail.

Hiking on the west side of the Big Island can be a hot and arid experience. The landscape is often barren lava or scrubby growth. If it’s scrubby growth, chances are that kiawe trees (Prosopis pallida) are prominent and if they are, it’s wise to tread carefully. That’s because kiawe trees produce long, tough thorns.

Hiking in slippahs (flip flops) is asking for trouble. A kiawe thorn will go through them like a knife through wet tissue. I’ve felt the jab of these thorns through my Tevas, which have robust soles of decent thickness. The first time I wore my new trail shoes, toward the end of the hike, crossing a kiawe-bordered beach, I felt a familiar prick in my foot. A thorn had buried itself in the ¾-inch thick sole and penetrated far enough to make itself felt. One of my routine tasks with my trail shoes, and the Tevas, is to examine the soles and extract any thorns with a pair of pliers. When a hike is over, it doesn’t mean the danger is past. Drive over one of these thorns and it can and does cause punctures.

But if all this makes it seem as if kiawes are reviled, that’s not the case. It’s widely used in smoking meats. The smell of burning kiawe is commonplace.

Kiawe isn’t a native tree; it originated in Peru. In fact, all Hawaii’s kiawes can trace their roots, as it were, back to a single seed planted by a priest in Honolulu in 1828.