626 FUNDAMENTALS OF FRUIT PRODUCTION 



in the growth of the varieties in question. Mean temperature during 

 the growing season, therefore, in this case becomes an accurate index of 

 adaptation to chmate. 



On the other hand the loganberry and sweet cherry which thrive so 

 well in the vicinity of Portland, Ore., cannot be grown profitably near 

 Portland, Maine, because minimum winter temperature is a hmiting 

 factor. The blueberry, which grows so luxuriantly near Portland, Maine, 

 fails to grow near Portland, Ore., not because temperature is a limiting 

 factor but presumably because it does not find a congenial soil. 



Investigations in fruit growing at Sitka, Alaska, show interesting effects of 

 a rather unusual chmate. From November to March inclusive the mean tem- 

 peratures are higher than those of Lewiston, Maine; they exceed those of Roches- 

 ter, N. Y., for nearly the same period and for December to February they are 

 somewhat higher than those of Martinsburg, W. Va. Zero temperatures are 

 very rare; nevertheless winter killing is common. Records of the Alaska Agri- 

 cultural Experiment Stations show that such hardy plums as De Soto and RoU- 

 ingstone, numerous apple varieties selected for hardiness, the sand cherry and 

 blackberries have suffered considerable injury. 



The causes of this condition are indicated in the following quotations from 

 reports of the station: 



"Only early maturing sorts will succeed. Varieties which are summer 

 apples in the States will be fall apples in Alaska, and those which are fall apples 

 in the States will not mature at all in Alaska. The summer heat is not great 

 enough. In the coast region the season between frosts is long — longer, indeed, 

 by at least two months than in the northern tier of states. 



"In the larger portion of the coast region there is little, if any, damaging frost 

 between May 1 and October 1, and some seasons damaging frosts do not occur 

 until the end of October. The drawback to the climate in this region hes not 

 in too great cold, but, anomalous as the statement seems, in the lack of summer 

 heat. . . . The maximum temperature is more generally between 60° and 70°, 

 and some summers it will not go much above 60°. In the interior, on the other 

 hand, the summers are warm enough, at least in places but the season is too 

 short to hope to mature any but the earliest sorts and there is considerable doubt 

 if they will succeed."" 



"The excessive rainfall and continuous mild weather prolongs the growing 

 season until long into October. The young wood is soft and succulent, and 

 moderately cold weather the following winter kills it."^* 



"The winter of 1908-1909 was quite severe for this part of the coast region. 

 The temperature fell to 2° above zero and 3° above zero in January and Febru- 

 ary, respectively, and the cold period was protracted over many weeks. As a 

 consequence, the young growth produced in the season of 1908 was partly killed 

 in most cases, and in some cases entirely. "^"^ 



"Blackberries and dewberries cannot be grown successfully in any part of 

 Alaska. They have been tried repeatedly at the Sitka Experiment Station and 

 the attempt has always resulted in failure. The summer is not warm enough to 

 develop the fruit and the plants usually winterkill even in mild winters, probably 

 due to the late succulent growth resulting from the abundance of moisture."^® 



