Describes experiments aiming to estimate the protection afforded by a shelterbelt on the plains area of America. Describes three test houses and gives test results. The three houses were unprotected, partially protected and closely protected by a slat fence. Gives basic data in the form of fuel use, wind and temperature. Concludes that the reduction in wind speed by windbreaks is of the general order of 35% with a proportional saving in fuel. Finds that the area of tree shelterbelts has themost important effect on the degree of wind reduction. Mentions the effect of shelterbelts on snow drifting.