Humus systems in the Caspian Hyrcanian temperate forests

This study investigated all available researches on humus of the Caspian Hyrcanian forest ecosystems in order to find the relationship between humus forms and environmental factors. Based on this review it can be concluded that the most important environmental factors which affect the humus in the Caspian Hyrcanian forests are: climate conditions, above-ground biomass, forest canopy gap, soil fauna, landform and tree species composition. We also found that morphological classification of humus is a suitable tool to study humus forms in these ecosystems.