The Anjozorobe forest is part of a branch of the eastern rainforest that runs along the Angavo scarp. The forest lies on metamorphic rock, and the terrain is mountainous and deeply dissected, with steep eroded slopes. The Mananara river, a tributary of the Betsiboka, flows across the western part of the site, which is also crossed by other rivers such as the Sahavila. The main vegetation is mid-altitude, dense, humid evergreen forest. Typical tree genera in the canopy are Canarium, Dilobeia, Diospyros, Eugenia, Protorhus, Sloanea, Schefflera, Tambourissa and Weinmannia. The mid-stratum includes trees/shrubs (Croton, Oncostemum, Vernonia), tree-ferns Cyathea and screw-pines Pandanus. Palms are relatively rare.
See Box and Tables 2 and 3 for key species. Eighty species are known from the site, of which 50 are endemic to Madagascar. Most of the species that are restricted to humid forest can be found.