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REPORT OF THE COMMISSIONERS OF 



The area devoted to forestry experiments at this place is divided into three 

 distinct terraces, the lowest lying in a creek valley and presumably receiving water by 

 absorption from the stream; the middle terrace receives a small amount of water from 

 springs; while the upper terrace is entirely without any opportunity for artificial 

 supply of water. Trees have been successfully grown on all three terraces. In the 

 annual report of the agricultural experiment stations of the University of California 

 for the years 1895-96, 1896-97, it is stated that there are few places in California 

 where the climate is as favorable for the successful culture of a large number of species 

 of plants and trees as it is at Santa Monica. The records show, however, that in 

 extremely dry years trees sometimes suffer from drought. 



The experience gained at these two California forestry stations is specially 

 interesting because there are at both of them several months in the year when there is 

 absolutely no rainfall. Thus, at Chico, in 1892, there was no rainfall in the months of 

 June, July, August and September. At Santa Monica, in 1892, rainfall was entirely 

 absent from June to October, inclusive. At Santa Monica, in 1895, the rainfall 

 of May was 0.08 inches, June, July, August and September, nothing and 

 October 0.18 inches. 



The reasons why forest and other trees grow under such conditions of slight rain- 

 fall are explained by Professor E. W. Hilgard in Bulletin No. 121 of the University of 

 California Agricultural Experiment Station — The Conservation of Soil Moisture and 

 Economy in the Use of Irrigation Water. Professor Hilgard says that the surprisingly 

 successful growth of deciduous trees without irrigation in California and despite a 

 drought of five or six months, leads to the conclusion that a less amount of water may 

 suffice under arid conditions, especially since in the East a few weeks of drought will 

 frequently destroy many kinds of trees. 



As to why forest trees endure drought better in California than in the East, 

 Professor Hilgard points out that the main cause is to be found in the much deeper 

 rooting of all plants in that arid climate whereby not only a much larger bulk of moist 

 soil is at their command, but the roots are withdrawn from the injurious effects of the 

 hot, dry surface and air. 



Professor Hilgard says this deeper rooting is not the result of foresight on the part 

 of the plant ; it could not occur on eastern soils because in the majority of the cases 

 the subsoils are impenetrable. On the other hand, in California, as a rule, subsoils in 

 the eastern sense do not exist; the soil mass is practically the same for several feet 

 and is very readily penetrable to great depths. This is due to the slight formation of 

 clay and the rarity of heavy rains in California. Moreover, this easy penetrability of 

 the soil implies that being well aerated the depths of the soil are not raw as in the East 

 and that, therefore, the subsoil may fearlessly be turned up as deeply as the farmer is 



