Agarwood, also known as oud, oodh, agar, aloeswood or lign-aloes, is a dark resinous heartwood that forms in Aquilaria and Gyrinops trees (large evergreens native to southeast Asia) when they become infected with a type of mould. Prior to infection, the heartwood is odourless, relatively light and pale coloured; however, as the infection progresses, the tree produces a dark aromatic resin in response to the attack, which results in a very dense, dark, resin embedded heartwood. The resin embedded wood is commonly called gaharu, jinko, aloeswood, agarwood, or oud (not to be confused with bukhoor) and is valued in many cultures for its distinctive fragrance, and thus is used for incense and perfumes.