Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. It tries to balance three things: the environment, the economy and society.A biological resource, such as timber or fish, is used sustainably if it is harvested no faster than it can be replaced by growth and reproduction. The population then stays stable and can be harvested indefinitely.Worked example: a forest regrows 400 m3 of timber each year. Harvesting 600 m3 a year removes more than is replaced, so the forest shrinks. The largest sustainable harvest is 400 m3 per year.Sustainable timber production uses:
• coppicing: cutting trees near the ground so that many new stems grow from the stump, to be cut again years later;
• selective felling, removing only some mature trees so the habitat remains;
• replanting at least as many trees as are felled;
• certification schemes, such as the FSC, so buyers can choose timber from sustainably managed forests.Sustainable fishing uses:
• quotas that limit the catch to around the maximum sustainable yield, the largest catch that can be taken each year without reducing the population;
• a minimum net mesh size, so young fish escape and reach breeding age;
• closed seasons during breeding, and no-take zones where fishing is banned.Sustainability links conservation to human needs: if resources are managed sustainably, people can benefit from them without driving species to extinction.
• coppicing: cutting trees near the ground so that many new stems grow from the stump, to be cut again years later;
• selective felling, removing only some mature trees so the habitat remains;
• replanting at least as many trees as are felled;
• certification schemes, such as the FSC, so buyers can choose timber from sustainably managed forests.Sustainable fishing uses:
• quotas that limit the catch to around the maximum sustainable yield, the largest catch that can be taken each year without reducing the population;
• a minimum net mesh size, so young fish escape and reach breeding age;
• closed seasons during breeding, and no-take zones where fishing is banned.Sustainability links conservation to human needs: if resources are managed sustainably, people can benefit from them without driving species to extinction.