This cell type is found in both the xylem and phloem. Resin duct numbers are also increased in species with these features. Flooding initiates production of low density cells and more intercellular spaces in the xylem, phloem and bark to facilitate oxygen transport and removal of toxic materials. This tissue forms by cells dissolving and cell walls separating to form a spongy mass of cells with large air spaces. Most trees will immediately slow or stop growth under flooded conditions.
Old myths suggest trees grow larger in diameter when flooded.
A diameter increase can occur in some species caused by bark and wood tissues producing more spaces between cells, and producing larger cells with thinner walls. This low density tree tissue around the outside of a tree can represent a large diameter growth spurt. In some trees, this growth pattern may be a prelude to final rapid decline and death. Flooding can also initiate many adventitious roots on the submerged stem area and large roots. The more flood tolerant the species, the more likely the species will form adventitious roots.