XXXIII. THE ROCK MAPLE. 493 



lindens, the hickories and the walnuts, is watery and sweet, 

 and contains crystallizable sugar ; but none so abundantly as 

 that of the Sugar Maple. 



The Sugar Maple should not be tapped before it is twenty-five 

 or thirty years old ; but the process may be repeated annually 

 as long as the tree lives. Some trees have been tapped for more 

 than forty successive years without apparent injury. Other 

 trees have had their growth retarded by it. This is probably 

 more owing to the wound necessarily inflicted, than to the loss 

 of the sap, as it is found that the quantity and quality of the 

 sap yielded are visibly improved after the first tappings. The 

 quality varies with the situation of the tree. In the forest, sur- 

 rounded by other trees, and having comparatively few branches 

 and leaves, a tree yields but one pound of sugar for five or six 

 gallons of sap ; when growing in the open ground, where it is 

 exposed to the action of the sun through the year, a tree yields 

 a pound from four and sometimes even from three gallons. The 

 average quantity is from twelve to twenty-four gallons each 

 season. In some instances it is much greater. A gentleman* 

 of Bernardston informs me that a tree in that town about six 

 feet in diameter, favorably situated, produced, in one instance, 

 a barrel of sap in twenty -four hours. The quantity depends 

 also on the number of openings made in the tree. 



The sap from trees growing in the maple orchards, gives an 

 average of one pound of sugar to about four gallons of sap ; 

 varying considerably in different years. One gentleman in 

 Bernardston made 300 pounds from CO trees; another 400 

 pounds from 100 trees; a third 500 pounds from 150 trees. 

 Some trees will give 10 pounds; some, more. Dr. Rushf cites 

 an instance of 20 pounds and one ounce having been produced, 

 within nine days, in 1789, from a single tree, in Montgomery 

 Co., N. Y.; and Michaux quotes the Greensburgh Gazette as 

 his authority for saying that 33 pounds have been made in one 

 season from a single tree. Mr. Lucius Field, of Leverett, in- 



* Henry W. Cushman, Esq., to whom I am indebted for much valuable infor- 

 mation upon this subject. 



f Dr. Benjamin Rush's Letter to Thomas Jefferson, on "the Sugar Maple Tree," 

 in the 3d Vol. of the Transactions of the Amer. Philosophical Society, 1st series. 



