Deciduous trees and plants have been promoted as a means of controlling solar heating and cooling. When planted on the southern side of a building in the northern hemisphere or the northern side in the southern hemisphere, their leaves provide shade during the summer, while the bare limbs allow light to pass during the <answer>winter</answer>. Since bare, leafless trees shade 1/3 to 1/2 of incident solar radiation, there is a balance between the benefits of summer shading and the corresponding loss of <answer>winter</answer> heating. In climates with significant heating loads, deciduous trees should not be planted on the Equator facing side of a building because they will interfere with <answer>winter</answer> solar availability. They can, however, be used on the east and west sides to provide a degree of summer shading without appreciably affecting <answer>winter</answer> solar gain.
The placement of deciduous trees on the Equator facing side of a building can have a negative effect on solar availability in which season?
winter