Although they could be considered as Class A foams, short-term forest fire retardants deserve a special consideration by the field-of-use. They have to be used at mixing ratios between 0.1% and 1% depending if the foam is used as a wetting agent or if it is preferred to be applied as structural foam, stuck to trees and bushes extinguishing the fire and conferring great resistance to reignition. They should be able to be used in land-systems (foam nozzles, fog-stream, high pressure) as well as air-systems (planes, helicopters, hydroplanes). Due to the systems they are used in, they have to possess good anti-corrosion properties in materials such as iron, brass, aluminium, magnesium, etc. - commonly used in the aeronautical sector. Also the foams need to have the lowest environmental impact possible, allowing therefore the re-germination of the plants in the treated territory.