324 TRANSACTIONS OF THE 



five to sixty inches, without any accompanying change of mountain for- 

 mation adequate to the production of such a result. 



Professor John LeConte, in discussing this increase of rainfall, says that 

 it " is a striking but very puzzling fact. We are not yet prepared to offer 

 any satisfactory explanation of it. So far as we know, there are no obser- 

 vations indicating any sharp and sudden depression in the temperature of 

 the ocean waters just at Cape Mendocino." 



One factor of this increase is the vast forests which act powerfully both 

 as attractors and condensers of moisture. While the Coast Range, even 

 south of San Francisco, is covered with timber, the forests do not compare 

 in extent with those which clothe the higher ranges of the north. The 

 sudden increase of the annual rainfall is coincident with the commence- 

 ment of these forests. 



The verdict of the most eminent authorities on this subject is by no 

 means unanimous. A very small minority claim that the effect of forests 

 is nil. The very great majority assert that they have an effect; some 

 claiming that they only act by retaining moisture, others that they sensi- 

 bly increase the rainfall. They base their opinion upon the changes pro- 

 duced by cultivation and tree planting, as well as by the disastrous effects 

 of mountain denudation. 



In a very able paper which appeared in the transactions of the State 

 Medical Society for 1883, Dr. Chipman discusses the subject, and brings 

 strong evidence to support the judgment of those who believe in an increase 

 of rainfall. It is possible that tree planting has not, as yet, had any great 

 influence, for the land so redeemed is of small extent, and the trees but of 

 a few years' growth. The results following denudation should be the cri- 

 terion. 



Certainly a densely wooded country and a large rainfall go together. 

 Of course, it may be claimed that the forests are a result, rather than a 

 cause; but the result of the destruction of immense forests has been so 

 pronounced as to render the converse probable. 



Should it be a fact that these moisture-attracting forests aid powerfully 

 in increasing the rainfall, we can, with certainty, predict a result that will 

 soon occur in the distribution of rainfall on this coast. 



Man, after a most reckless fashion and with all modern appliances, is 

 rapidly destroying what nature during the last thousand years has so gen- 

 erously produced. Within twenty years the mountain sides will be bare, 

 and where redwood measuring fifty and sixty feet in circumference stood 

 thickly rooted, dead stumps will be the only proof of former grandeur. 



Some contemplate this change with alarm. In. all probability the results 

 will be extremely gratifying. The immense forests no longer attracting, 

 the rain-laden clouds will be more evenly distributed, the rainfall in the 

 southern counties largely increased, and artificial forests may yet clothe 

 their hillsides, materially modifying their heat and purifying the atmos- 

 phere, causing the now barren plains to bloom, and thus add new charms 

 to a region already famous as a sanitarium. 



The topography of Northern California will assure to that region a boun- 

 tiful supply of rain, though it may no longer be deluged with the six feet 

 of water which falls during its five Winter months. 



This is not altogether theoretical. Already have vast tracts of forests 

 been destroyed, and the result has been a most wholesome change in the 

 climate. The annual rainfall has perceptibly diminished and the fogs 

 which, formerly, during the Summer, enveloped this region, are growing 

 lighter yearly. 



So pronounced has this change been in Crescent City that the climate. 



