Neem trees, like other trees, can purify natural air and keep the oxygen level in the atmosphere balanced. Neem is able to withstand extreme heat and water pollution. Neem trees help to improve fertility of the soil and to rehabilitate degraded wastelands. Furthermore, the neem tree can play a vital role in controlling soil erosion, salination and preventing floods. 

During hot weather, the temperature under neem trees is about 10° C less than the surrounding temperature. This way, the trees restore the health of degraded soil. The litter of falling leaves improves soil fertility and the organic content even further.

Furthermore, the neem tree serves as a shelter to many useful organisms, such as bats, birds, honeybees and spiders. Honeycombs established on the neem tree are free from the galleria wax moth infestation. 

Being a hardy, multipurpose tree, it is ideal for reforestation programs and for rehabilitating degraded, semiarid and arid lands. During a severe drought in Tamil Nadu State in June-July 1987, it was witnessed that neem grew luxuriantly, while other vegetation dried up. 

Neem is also useful as windbreaks and in areas of low rainfall and high wind speed. In the Majjia Valley in Niger, over 500 km of windbreaks, comprised of double rows of neem trees have been planted to protect millet crops which resulted in a 20% increase in grain yield. Neem windbreaks on a smaller scale have also been grown along sisal plantations in coastal Kenya. Large scale planting of neem has been initiated in the Kwimba Afforestation Scheme in Tanzania. In countries from Somalia to Mauritania, neem has been used for halting the spread of the Sahara desert.