Populations have been dramatically reduced because
of irrational and uncontrolled exploitation for its valuable wood (Reitz et al., 1988). Brazilian pine
is also valued as an ornamental plant and its starchy
seeds are an important food source for animals. Much
effort at reforestation in southern Brazil is concentrated
on fast-growing exotic species of Pinus and
Eucalyptus. Araucaria angustifolia is today classified
as vulnerable in the IUCN list of threatened species
(Hilton-Taylor, 2000), and timber harvest is forbidden
by law. However restoring populations will require
introducing new individuals on degraded forests and
deforested areas. The success of such an action will
depend, among many factors, on a profound knowledge
of ecological and physiological aspects that are
relevant for the natural regeneration and for the establishment
of planted individuals. One of these is
the ability of seedlings to efficiently harvest nutrients
from the soil, and this ability is strongly determined
by the mutualistic association between mycorrhizal
fungi and tree roots.