Mycorrhizal fungi are ubiquitous components of most ecosystems throughout the world
and are considered key ecological factors in (1) governing the cycles of major plant nutrients
and (2) sustaining the vegetation cover. Two major forms of mycorrhizas are usually
recognized: the arbuscular mycorrhizas (AM) and the ectomycorrhizas (ECM). The lack of
mycorrhizal fungi on root systems is a leading cause of poor plant establishment and growth
in a variety of forest landscapes. Numerous studies have shown that mycorrhizal fungi are
able to improve the survival and early growth of various tree species in the field. Mycorrhizal
association is estimated to occur in 95% of native undisturbed vegetation, whereas it occurs in
less than 1% of vegetation from disturbed sites. Thereafter, mycorrhizal symbiosis has to be
reestablished at these latter sites to benefit from the mycorrhizal effects on plant growth. This
can be achieved by enhancing the mycorrhizal status of seedlings before they are transplanted
to disturbed sites. It is necessary that nurseries produce tree seedlings associated with
mycorrhizal fungi that are ecologically compatible with the tree species and the planting sites
to make afforestation successful. According to these conditions that have to be taken into
account, different methods of mycorrhizal inoculation have been identified to optimize fungal
effects on plant growth. The main objective of this chapter was to describe some methods to
obtain mycorrhizal seedlings at the nursery and to present some tree growth data resulting
from the use of mycorrhization under such conditions in Madagascar.