Simply put, Sustained Yield Use is a form of forestry and natural resource management that aims at "not killing the hen that lays the golden egg". While the concept is mainly used for natural resources, particularly forestry, and fishing, it can, however, also be applicable to all economic activities with a capital resource, production timeline, consumption, and surplus management. Sustained yield ensures the feasibility of continuous, long-term exploitation of available resources to obtain regular harvests. Sustained yield use is most commonly actively applied in forestry. Forest management goes back to Feudal
U.S. Multiple-Use Sustained Yield Act of 1960
Forests are valuable national assets and constitute multiple resources within a unit. There could be a variety of trees, wildlife, rivers and leisure hot spots. Each of these constitutes a natural capital base, from which yields are extracted optimally, without jeopardizing the sustainability of each resource. The
Sustainable yield in fisheries is the amount of fishing that can be done without reducing the population density of the species, i.e. the surplus to maintain the ecosystem. The virgin population of the species decreases with fishing activity, hence it needs to be balanced with the time the species needs to breed and develop. The sustainable yield would be within the range of the population density and its capacity to reproduce. Fisheries also use the concepts of maximum, optimal and annual sustainable yields. The first is exactly half the carrying capacity of the species by the ecosystem. Population growth is highest at this stage. Optimal sustainable yield represents the highest difference between total revenue and cost. It is typically lower than maximum sustainable yield. The third is the harvest, which can be obtained without lowering original population numbers.
Volatility In Sustainable Yields
It can often be difficult to quantify sustainable yield because ecological conditions are dynamic. There can be factors other then harvesting, which can cause fluctuations in the natural resource levels and its reproduction. Sustainable yield also varies over time because of the maintenance requirements of the natural capital and the ecosystem. A forest that suffers fire or sudden flooding will require more production to attain pre-catastrophe levels. During this time, the sustainable yield can be quite less.