REGULATIONS, $1,000 APPLE SEEDLING PREMIUM. 373 



11. After making' entry with the secretary all further communica- 

 tions on the subject by the person making- the entry may be ad- 

 dressed to the chairman of the awarding committee. 



12. The committee shall keep a record of all its proceedings and 

 report to the executive board whenever called on, and to the society 

 at its annual meeting. 



A. W. Latham, 

 Minneapolis, Minn., Oct. 1, 1899. > Sec'y. 



EVAPORATION OF DORMANT TREES. 



The chief factor which defines the areas of the profitable growing 

 of fruits and fruit trees, as is the case with all agricultural crops, 

 is climate. The main factor of climate is temperature. The fruit 

 growing area may be divided into climatal fruit-zones, bounded by 

 the isotherms, or lines of equal temperature. 



The second important factor of climate is moisture. The fruit grow- 

 ing area of the United States, may be divided into three zones 

 by the isohyetals, or lines of equal rainfall, the Atlantic zone, 

 bounded by the Mississippi river on the west, the plains zone, ex- 

 tending westward to the mountains, and the Pacific zone. The 

 Atlantic zone is quite moist, while the plains and Pacific zones are 

 comparatively dry. The plains zone, in which we live, is perhaps 

 the most trying to fruit trees, on account of the hot, dry winds of 

 summer and the cold, dry winds of winter, which cause excessive 

 evaporation through the bark. Serious injury to trees is very liable 

 to occur in winter, because evaporation goes on when the ground 

 is so deeply frozen that the roots cannot supply any moisture. 



The extent to which evaporation takes place through the bark of 

 dormant trees may be determined by experiments. A series of such 

 experiments have been commenced at the state farm, by Mr. Cut- 

 ting and myself, only one of which has as yet been completed. The 

 experiment is as follows: On November 7, four twigs were cut from 

 an apple tree in the orchard and brought to the laboratory. They 

 were then shortened down to about a foot in length, the object of 

 this second cutting being to leave as little time as possible between 

 the cutting and the weighing. The cut ends were then immediately 

 dipped in melted paraffine to prevent evaporation, except through 

 the bark and buds. The twigs were then weighed and put in a place 

 as much exposed as the tree from which they were taken. They 

 were weighed at frequent intervals for one week, and a record kept 

 of the losses from time to time. They were as follows: 



Twig No. 1: original weight, 5.357; loss in 24 hours, 10 centi- 

 grams; in 54 hours, 17 centigrams; in 78 hours, 25 centigrams; and 

 in one week, 43 centigrams. Twigs No. 2 and 3 showed similar re- 

 sults. These three twigs were all of the last year's growth. The 

 average loss in these twigs was about eight per cent, of the origi- 

 nal weight. Twig No. 4, was cut from a branch three years old. Its 

 loss was only very slightly less than that of the other twigs in pro- 

 portion to the bark surface exposed, but this slight difference was 

 probably due, in part at least, to the greater number of buds in the 



