The city forest of Frankfurt is one of the oldest managed forests in the world. Purchased in 1373 from the Emperor Karl IV, it not only still provides timber and wood products, it plays an important role in the purification and supply of the city's water, and helps to regulate the temperature and air quality of the city. Perhaps the most visible impact it has on the city is its role in providing recreation for its citizens. Within the city are bicycling, walking, and horseback riding trails, and various other sports and educational facilities.

Not only does the forest provide a large amount of Frankfurt's water supply, it also serves as an important component in the purification of water that is fed into it through perforated pipes from a water treatment plant. As it filters through the earth, the water then flows west along an aquifer that is then tapped for use. Since the groundwater of the forest is so vital to the wellbeing of the city, no chemicals are used in its grounds. A retention pond collects the runoff, preventing it from contaminating the ground water, from a nearby hill that was created from a landfill.

In addition to filtering the pollution created by the airport and highways that cut through the forest, the forest also helps to cool the temperature of the city. Since some of the prevailing winds originate in the southwest of the city, the forest not only filters, but also cools and humidifies the air in summer, and potentially serves as a buffer to slow down the cold winds in winter.

An intensive succession method of forest practice is used. Foresters continuously plant and thin the forest as they see appropriate for its health and provided benefits. Although pine was most prevalently planted after the Second World War, there is now a greater diversity of species that have been planted according to various factors, such as soil condition, and proximity to paths. The expenses required to maintain the forest are mostly paid through taxes, although the forest is able to collect some significant revenue from commercially sold wood and airport fees.