AREA OF POSSIBLE DRY-LAND OLIVE CULTURE. 35 



trees and trees of several varieties i)laiite(l in 1908 were with one 

 exception killed to the ground under conditions where the minimum 

 temperature reached was only 18° F. After mild weather during 

 the latter part of December and the early part of January, with 

 maximum temperatures of 76° and 77° on January 9 and 10 and 63° 

 F. on the following day, a "norther" brought the temperature to 

 20*^ at 3 p. m. on January 11, with a minimum of 18° F. at night. 

 On January 12 the minimum was 18° with a maximum of only 22°, 

 and there was a minimum of 22° on the morning of January 13, the 

 temperature thus being maintained about forty hours at from 10° to 

 14° below freezing. These trees were in a plat which in accordance 

 with the general cultural policy of the farm had been kept under 

 fine surface tillage, enabling the soil to store abundant moisture from 

 the season's rains. This arrangement prevented the olive trees from 

 entering the dormant condition necessary to their resisting the low 

 temperatures, and the freezing sap burst the bark of most of them 

 and killed all to the crown, from which they sprouted again freely. 



At Boerne, 30 miles northwest of San Antonio and 700 feet higher 

 in altitude, the temperatures registered were 1° lower each day of this 

 cold spell than those at the San Antonio farm, yet the olive trees 

 there sustained much less injury. 



A region may have monthly mean temperatures and an annual 

 mean sufficient to place it high in the scale when compared with well- 

 known olive regions, yet where high winter means include sudden 

 drops and low minima the trees will suffer all the more severely. As 

 an example, the monthly mean temperatures at San Antonio are 

 higher throughout the year than those of Fresno, Cal., or of Catania, 

 in Italy, and excepting only the autumn months, liigher than those 

 of Sfax, in Tunis, three representative olive-producing regions. 

 Yet the liabihty to the sudden advance of cold waves may upon 

 experimentation be found to exclude this portion of Texas entirely 

 from the olive-growing belt. 



It seems probable also that there is a considerable difference in 

 olive varieties in resistance to cold, and an inviting. field for experi- 

 mentation is here offered. 



The high altitudes of the greater portion of New Mexico will 

 doubtless exclude the olive on account of too severe cold. However, 

 it seems probable that favored mesa sites may be found in the south- 

 western portion of the Territory, particularly in Grant and Dona 

 Ana counties, where the olive may be grown. 



French authorities "^ give the maximum range in altitude for the 

 olive as from 500 meters (1,600 feet) in France and northern Italy to 



a Investigation Made by the State Board of Horticulture of the California Olive 

 Industry, Report to Governor Gage, 1900, p. 8. 



192 



