Abstract: According to the results investigated in northern Linze Oasis for tree and shrub mixed sand-holding forests, the degree of wind reduction and micro-climate improvement increascs with the growth of afforestation years. After 8 years of afforestation, sand dune has been stabilized, wind speed is reduced by above 50%, air relative humidity increased by 6—8%, and evaporation potentiality reduced by 43—60%. After 12 years, each ha of the forest can provide timber 262.8m³, firewood charcoal 39t and litterfall 51t(dry weight) which contains (NH₄)₂SO₄ 1873.5kg, Ca₃(PO₄)₂ 96 kg and KCl 2872.5kg. The net output is 53479.2 yuan ·ha^-1. This mixed sand-holding forest has gained both ecological and economic benefits. It is valuable to be popularized in arid areas.

Key words: Dissolved organic matter, Terrestrial ecosystem, Pollutants