The soil in the park is extremely unfertile, it is acidic with a high iron and aluminum concentration but little phosphorus. Most rainforests have unfertile soils but those of Madagascar are worse, this is reflected in slow tree growth and lower fruit productivity.
The terrain is extremely hilly with very steep slopes.
Wright, P., 1999, "Lemur Traits and Madagascar Ecology: Coping with an Island Environment", Yearbook of Physical Anthropology, 42: 1-42