Cooling effect of forests: Reforestation kept the eastern US cool. Measurements from the eastern United States show how big the effect is.
Reforestation in the 20th century probably caused a “warming hole” there. Since the 1930s, there has been a lot of reforestation, and around 15 million hectares of forest have been created since then. According to this, forests in the eastern U.S. could cool the land surface by 1 to 2 degrees Celsius on average annually. The effect is strongest at midday in summer.