Woodland Stage - Hydrarch
When the lowland has been built up to an extent where the soil is saturated perhaps only in spring and early summer, certain species of shrubs and trees may appear. Those that can tolerate waterlogged soil around their roots will be - the pioneers. Various species of Salix, Cornus, Cephalanthus, Alnus and Populus may form dense thickets.
Some shade-tolerant herbs may also grow among the trees and shrubs. These woody plants react upon the habitat by producing shade and by lowering the water table both by further building up the soil and by vigorous transpiration. By this time of succession there is much accumulation of humus wit rich flora of microorganisms like bacteria, fungi and others. Thus mineralisation o the soil favours the arrival of new tree species in the area leading to climax stage.