By Steve Sharrow, Oregon State University
One visible effect of including trees in pastures is the shady haven which they provide for livestock on hot summer days. The benefits of providing protection from the hot rays of the summer sun are obvious. After all, that is why we wear a hat! It easily follows that animals, which are unable to shelter from the direct sun during the heat of the day, will have to expend energy to deal with their discomfort and/or reduce their feeding activity. Their productivity should decline in proportion to the time spent under these unfavorable conditions. Increased livestock production during hot weather is often promoted by agroforesters as one of the benefits of having trees. However, there is very little published research available to either verify or disprove this widely held belief.