AGRICULTURAL RESEARCH IN NEW HAMPSHIRE 29 



lected from three different locations in the state. They were placed in 

 shaded beds in the greenhouse and in shaded sash-covered beds outside. 

 The amount of rooting was not as great as during the previous season. 

 The highest per cent of rooting was with Hormodin, 33 per cent, but on a 

 small number of cuttings. The average of all rooted lots was 9.6 per cent. 

 No rooting occurred in the outdoor beds. 



These cuttings were removed to the forest nursery in August. The 

 leaves were shed promptly, but the condition of the cuttings could not be 

 determined until spring, when it was evident that none of them had sur- 

 vived the winter. It seems clear that it is not a satisfactory procedure to 

 move them until the following spring, without taking more than ordinary 

 precautions. Several different methods of handling rooted cuttings will be 

 tried during the coming year. 



In the sap quality study a series of eight sugar maples were tested each 

 day, and, on one occasion, every hour during the daily run. The quantity 

 of sap produced was measured when weather conditions made it possible. 

 The pH content w^as determined at_ frequent intervals for more than 200 

 samples by Dr. Joseph Seiberlich of the Engineering Experiment Station. 

 The average of all tests showed a pH of 6.638, and the range was 6.03 to 

 7.23. 



In general, it may be said that the sugar content of the sap was high- 

 est during the early part of the season, decreased gradually, but showed a 

 tendency to increase toward the end of the season. All trees followed the 

 same trend but on most days the relative sweetness of the sap remained 

 about the same, /. e., the sweetest trees at the start still yielded the sweet- 

 est sap at the end of the season. Similarly, hourly tests of the sap indi- 

 cated that the highest sugar content is obtained during the first run in the 

 morning, and the sweetness gradually declines during the day with a slight 

 rise toward evening. 



The sweetest trees produced the most sap. The sap from these trees 

 seemed to be running faster than from the others, but there is also some 

 evidence that these trees started running earlier in the morning than did 

 the others, and ran until later in the afteroon. 



The acidity of the sap varies somewhat from tree to tree and from day 

 to day, but it was evident that all the trees showed the same trend, all be- 

 ing more acid on some days and less acid on others. Although the data 

 are not conclusive because the sap tested was not always fresh, it appears 

 that there is some correlation between the acidity and the sugar content; 

 on days when the pH is low the per cent of sugar present is also low. Fur- 

 ther investigation of this point is needed to determine the causes of varia- 

 tion in acidity. 



In an attempt to correlate the weather conditions with the quantity 

 and quality of sap, an instrument shelter was set up in a red maple stand, 

 and three thermographs were installed to record the temperatures of the 

 air, of the soil, and of the interior of a tree. The air temperature in the 

 open was recorded by a thermograph housed in a second instrument shelter 

 maintained by the Department of Horticulture. Data on barometric pres- 

 sure and precipitation were obtained from the weather station operated by 

 the Department of Geology. No correlation between the weather and qua- 

 lity of the sap is evident as yet and further investigation is needed on this 

 phase of the problem. 



