sentences:  In the early 1900s a significant industry established within the forest and surrounding region harvesting bark from brown mallet trees ("Eucalyptus astringens"), a species of eucalypt which grows on and near laterite soils in parts of the southern wheatbelt.Bark sent to Germany for analysis was found to contain more than 40% of high quality, water-soluble tannins suitable for the production of quality leather by the process of tanning.By the mid-1920s, concerns were being raised about the ability of the area to maintain the supply of naturally grown mallet and by 1929, stands of the naturally grown mallet had almost disappeared.