78 TREE PLANTER'S MANUAL. 



its forests. Heavy floods and severe drouths were the result; replanting of 

 forest trees toward the close of 1700 resulted in a more uniform rainfall 

 and its better distribution. Subsequent destruction of the forest have 

 again brought back the original condition of affairs." Prof. Becquerel also 

 tells us that when discovered in 1815, the Island of Ascension "was barren, 

 and so destitute of water that supplies were brought to it from the main- 

 land. The effects of planting trees resulted in increased rainfall." 



Prof. Fernow says: "While the forest everywhere does not increase 

 precipitation over its own area, yet a large system of forests over an 

 extensive area will influence the quantity of precipitation over and within 

 this area." 



Prof. Harrington cites reports from sixteen meteorological stations 

 in Germany that are always near forests, and 16 like stations near regions 

 without forests, and in most every instance the forest station shows the 

 more rainfall. That at Lintzel was made a date of comparison with a 

 series, being a reforested district. The results are given after the accum- 

 ulating tree-plantation was five years old, and it was discovered that com- 

 mencing 1882 and ending 1888, the percentage of rainfall increased steadily 

 with the extent and height. Experiments were also made on forested and 

 non-forested elevations, covering vast areas, and again the forest led in 

 percentage of rainfall until at the highest point it was nearly double in 

 surplus. After mentioning striking instances in India, Java arid Celebes, 

 covering many years of experiment, and allowing a margin of fifty per cent 

 for errors and general rainfall, the professor cautiously adds, "There yet 

 remains an appreciable addition which might be attributed to the growing 

 forest; * * * makes a good presumption that a forest does actually 

 increase the rainfall to an appreciable percentage." 



Notwithstanding the accumulating evidences that forests promote rain- 

 fall, there are prominent meteorologists in our country, of prudent 

 research, who maintain "there are no evidences to show that forests cause 

 an increase of rainfall." Fortunate for forestry, a world-wide discussion 

 on the subject is evoked, which, on comparing notes, will sooner establish 

 the truth in favor of the trees; and we of the Northwest, where trees are 

 precious, can patiently afford to await developments, confident that the 

 natural coolness of a massive forest condenses atmospheric vapors to pre- 

 cipitation, where other conditions are favorable. 



"BLOOD OF THE EARTH." 



Differ as we may, all agree with Prof. Marsh, alluding to trees serving as 

 equalizers of temperature and moisture, that "when man destroys these 

 natural harmonizers of climatic discords, he sacrifices one of the most con- 

 servative powers of nature, and does himself great injustice and harm;" 

 and with Cassius M. Clay, of Kentucky, who thus strongly sums up the 

 whole problem: "Forests are the blood of the earth, and in their destruc- 

 tion follows the death of nations." 



LAWS OF PRECIPITATION. 



Heat expands moisture; cold condenses it. 



Warm air can contain more moisture or vapor than cold air. 



