Geneticist Zhang Huarong walks through the forest near his Hong Kong research lab, gesturing towards a rotting incense tree stump that is one of over a dozen illegally felled for the valuable wood inside. A stone’s throw from the city’s urban centre are forests home to trees that produce fragrant — and valuable — agarwood, used in a number of high-end products from incense and perfume to traditional Chinese medicine. Environmentalists say illegal incense tree felling is on the rise in Hong Kong, fueled by black market demand. Scientists like Zhang are fighting back by taking DNA samples from each plant and creating a database that can help authorities crack down — as well as offer insights into how the trees can be better conserved …Hong Kong has long been a hub for sweet-smelling aromatic products. The city’s name — translating to “fragrant harbour” — is commonly linked to the area’s history of incense production and sale.