Gaharu or Eaglewood is an amazing patologic phenomenon. The substance is formed when a damaged Aquillaria reponds to bacterial or fungal attack. The damages trees produce a king of fragrant protecting resin/oil that gradually hardens and turns into black lumps.

Gaharu is commonly used to make high-quality incense. The Chinese describe it as a "nice, profound yet balanced" fragrance. Due to its high price on the market (reaching USS 400 / kg), the substance is hunted by many. Systematic hunting for the species starts from Sumatera, Kalimantan and Papua Nugini. The high market pressure has led to uncontrolled, destructive and unsustainable exploitation of the species and threatened its existance.