Effect of forest shelter-belt as a regional climate improver along the old course of the Yellow River, China

Abstract

Up to now very few case studies have provided evidence of the effect of large regional increases in forest area on improving regional climate. This article is perhaps the first description of a unique positive case study of the increasing protection provided by reforestation in controlling a formerly disastrous climate, where gale days have decreased by 80 % per year, and maximum wind speeds of gales have decreased on average from 26 to 11 m/s, while overall average annual wind speed has decreased by 90 % near the ground surface when forest coverage has increased from 3 % in 1950s to 36.9 % in 2010s within 60 years, changing the long-term trend of sandstorms and desertification into a wetter climate where disastrous droughts are now rare despite a global megatrend of decreasing forest area and climate warming. The local climate has been improved by reducing the extreme highs in temperature, reducing the power and frequency of gales, and increasing the number of foggy days. Thus, we propose in arid and semi-arid regions, billions of trees may have a direct effect on improving regional climate, which is worth attention to more than just because of its function as a carbon sink.