This also is a question for local study. Over large sections of the country a tree shelter on the south is desirable, as the violent winds come from that quarter at the period when orchard fruits are maturing. But on the Atlantic and Pacific coasts windbreaks are often desirable, as a protection from ocean winds and storms. In Minnesota and the extreme northwest part of the plains east of the Rocky Mountains, the consensus of opinion of fruit-growers is in favor of protection on the north and west. But in south Minnesota, Iowa, Kansas, Nebraska, and parts of Missouri, a southerly tree protection is favored to protect in part from the hot winds from the southwest, and the storms from the Gulf that often cause the premature dropping of the fruit. Over this region protection on the north is a disadvantage, as it checks the free air-circulation needed in summer, and favors starting sap-circulation in winter, leading to sun-scald of the stems on the south side and in the forks. Close shelter also increases the liability to damaging frosts during the blossoming period and increases the liability to fire blight. But in all parts where large orchards are planted in rows running from north to south all the protection needed is given by the extended fruit-plantation itself. The north and south circulation between the rows is needed in summer and winter.

Over the comparatively level surface of the whole Mississippi valley the small fruits, such as strawberry, raspberry, and blackberry, are materially benefited by tree-shelter on the south and west to lessen evaporation from the drying winds prevalent during the summer from these points. With such protection less trouble is experienced from fungus attacks of leaf and bark and more even and perfect development of the fruit is secured.