Sweating encourages bud break (leafing out) in trees that are prone to dehydration, such as pecans and some varieties of mulberries. This is important in dry, cold or windy climates. Putting trees in an enclosed greenhouse with higher humidity is perhaps the easiest way to go, but not if you do not have a greenhouse. Alternately, the trees can be laid down and covered with two to three inches of wet sand or fir or pine shavings. Leave it until the buds start to break. The warmer the temperature, the faster bud break will occur. Make sure to keep the covering material moist.