Barren lands are located in areas with a climate that is very damp and humid. For instance, the Buck Creek barrens in North Carolina, in the last ten years the zone receives around 1770 mm of precipitation. The Nottingham Serpentine Barren are very humid and has an average temperature of 11 degrees Celsius. Here, the average precipitation averages at 1200mm and is spread out evenly throughout the year. Another region of barren vegetation is located in the Appalachian Mountains. In the low elevation of the northern part of this mountain chain, the annual precipitation is a little lower than on the southern Appalachians high peaks. In this location, precipitation falls mostly as rain rather than snow; and also precipitation occurs mostly in the summer.

Source:  wikipedia