Productive use values
This is the value of natural products harvested through commercial logging, agriculture or fisheries and medicines that generated products that are of commercial value. Logs still account for a significant proportion of world trade, although there is a trend towards value-added processing in the timber industry in developing countries. The export of timber in log form is increasingly being restricted, partly to retain wood within the country for further processing, and partly as a conservation measure.
This also includes the commercial value of products prepared using biological resources as opposed to subsistence use when they are directly consumed. For example, taxol from the Pacific yew tree yields medicines that are used for treating cancer; enzymes from leech saliva is used to produce medicines that dissolve blood clots during micro-surgery.