Forests are moderators of climate. They heat and cool slowly. Their slow response to change resists sudden changes, and, consequently, they mitigate the rudeness with which sudden changes are always accompanied. Sudden changes of temperature are often annoying and enervating to man, and frequently do severe damage to domestic plants and animals. They sometimes have what may be called an explosive effect upon the life-tissues of many plants and animals which man has domesticated and is producing for his benefit. Many plants have been domesticated and largely so specialized that they have been rendered less hardy. With good care, these plants are heavy producers, but, to have from them a premium harvest each year, they need the genial clime, the stimulating shelter, and the constant protection which only forests can supply. Closely allied to changes of temperature is the movement of the air. In the sea every peninsula is a breakwater: on land every grove is a windbreak. The effect of the violence of high winds on fruited orchards and fields of golden grain may be compared to the beatings of innumerable clubs. Hot waves and cold waves come like withering breaths of flame and frost to trees and plants. High winds may be mastered by the forest. The forest will make even the Storm King calm, and it will also soften, temper, and subdue the hottest or the coldest waves that blow. Forests may be placed so as to make every field a harbor. The air is an invisible blotter that is constantly absorbing moisture. Its capacity to evaporate and absorb increases with rapidity of movement. Roughly, six times as much water is evaporated from a place that is swept by a twenty-five-mile wind as from a place in the dead calm of the forest. The quantity of water evaporated within a forest or in its shelter is many times less than is evaporated from the soil in an exposed situation. This shelter and the consequent decreased evaporation may save a crop in a dry season. During seasons of scanty rainfall the crops often fail, probably not because sufficient water has not fallen, but because the thirsty winds have drawn from the soil so much moisture that the water-table in the soil is lowered below the reach of the roots of the growing plants.