96 



1917 ANNUAL REPORT 



Near our La Habra nursery the thermometer registered 1 1 2 in the 

 shade. In this nursery we had no budded trees at that time. There were 

 2000 Httle seedhngs of Mexican stock which had been planted from flats 

 with bare roots a few weeks before the "hot spell." We had about 10 

 per cent loss among these, and other seedlings which had been out long 

 enough to become established, were injured to some extent. 



Hie damage would probably have been greater had it not been for 

 the fact that the irrigating water was turned into the nursery the hottest day. 



W. H. Sallmon : While the most of Southern California was blis- 

 tering under temperatures in the nineties and hundreds from June 1 4 to 17, 

 reaching a maximum of 1 24 degrees at Mecca in Riverside county, San 

 Diego was favored with the lowest maximum, the Government thermome- 

 ter showing 87 degrees on the 14th, dropping to 77 degrees on the 15th, 

 and running to 82 and 85 degrees on the 1 6th and 1 7th. 



This condition explains the comparative immunity of San Diego and 

 vicinity from injury arising from the heat wave. 



One orchard of 150 trees, consisting chiefly of Challenge, Harman, 

 Walker and Puebla, was not afl^ected in the slightest. This orchard is 

 quite near the ocean on the east side of a ridge which separates it from 

 the Pacific. 



Another orchard of 250 trees, about 1 5 miles from the ocean, also 

 escaped except for one tree which stood in the shadow of a tent where it 

 received the heat reflected by the canvas. The leaves on this tree were 

 shriveled and the bark cracked. 



Another orchard of 280 trees, about 5 miles from the bay, consisting 

 chiefly of Puebla, Northrop, Fuerte, Dickinson, Taft and Perfecto, had 

 the foliage of all varieties severely burned. The tips of all young shoots 

 were burned off and the large leafage curled and blackened. The bark 

 was uninjured and the majority of the trees have recovered, though the 

 growth of the trees was evidently checked. There was no fruit on either 

 of these orchards. 



It may be that two of these orchards escaped, partly because irrigation 

 had closely preceded the heat wave, but it is significant that the trees in 

 the orchard which suffered most were surrounded by burlap while the trees 

 in the other two orchards cited were unprotected. It seems probable that 

 the reflection of the heat from the burlap was the chief cause of damage 

 to the orchard which suffered most. 



Dr. Lester Keller: The heat reached 103 degrees on the first 

 day. So far as damage was concerned, about five Dickinson trees were 

 lost, these being young trees without protection. Of the older trees, those 

 that had the water turned on were not burned. Those without water had 

 the tender growth injured in a few places. The trees least damaged were 

 Fuerte. These also were least injured by frost and "northers." If the 

 young trees had been protected there would have been no injury. 



T. H. SheddeN: Those four blistering days in June furnished us 

 much food for thought. Many surprises and contradictions developed. 



First: In many instances, the so-called hardy varieties of thin- 

 skins that so courageously weathered the winter, shriveled in the astounding 

 heat wave. 



Second: Many thick-skin and hard-shell varieties, suspected of being 



