186 BOARD OF AGRICULTURE. 



In the case of a tree tapped on the north and south sides 

 at the same level, it was found that the north spout jaelded 

 daily about twice as much sap as the south spout, and contin- 

 ued to flow nearly two weeks longer. The tree was tapped 

 March 19th, and produced seventy pounds of sap, containing 

 two and one-half pounds of sugar. The maximum flow from 

 this tree occurred March 23d, and amounted to ten pounds 

 three ounces, from two spouts. 



In order to discover whether the sweetness of the sap was 

 the same in all parts of the tree, a spout was inserted into a 

 healthy maple, which had never been tapped, at the usual 

 height, and fifty feet above this another spout was set into 

 the trunk, where it was about five inches in diameter. A 

 limb thirty -five feet from the ground was also cut oft' where 

 it was one inch in diameter. In seven hours the lower spout 

 had bled six pounds of sap, the limb two ounces, and the up- 

 per spout not a drop. Similar experiments on diflerent trees 

 showed that the sap flowed most freely within twelve feet of 

 the earth, and that the flow diminished rapidly above this 

 height. 



Experiments upon the roots of maples pi"oved that sap 

 flowed from both ends of a cut root, and that it all contained 

 sugar. 



While the average annual yield of ordinary trees in a sugar- 

 orchard is about sixty pounds of sap and two pounds of su- 

 gar, a tree in Leverett is reported to have produced in one 

 season fourteen hundred pounds of sap, which probably con- 

 tained more than forty pounds of sugar. 



There seems to be no good evidence that the bleeding of 

 trees or vines has any appreciable eflect upon their growth or 

 health. It is certain that maples have been tapped every 

 year for fifty years without diminution of their sugar-product, 

 or perceptible injurious consequences of any sort. 



The birches appear to exceed all other trees in the amount 

 of sap which they yield and the enormous pressure which 

 they exert upon the gauge. Four species, the black, the yel- 

 low, the paper and the gray or white birch, were tapped and the 

 daily flow of sap weighed. They were all tapped March 19th, 

 but did not bleed till the 25th, from which time they flowed 



