Man settled in the taiga causing great agricultural changes, sometimes dramatically decreasing coniferous forests.Humus-rich soil is excellent for farming. Corn, barley, oat, sugar beets, sunflowers and potatoes are grown there, while breeding concerns cattle, sheep and horses. Forests are also commercially exploited to make timber and cellulose pulp. Birches provide light and easily workable timber and produces a very strong and light cellulose, used to make airmail paper.