SAP OF SUGAR MAPLE. 181 



up by tlieir roots from the ground — for we can not extract from 

 a tree its whole moisture — but numerical data which may aid the 

 imagination to form a general notion of the powerful action of 

 the forest as an absorbent of humidity from the earth. 



The only forest-tree known to Europe and l!^orth America, the 

 sap of wliich is largely enough applied to economical uses to have 

 made the amount of its flow a matter of practical importance and 

 popular observation, is the sugar maple, Acer saccharmum, of 

 the Anglo-American Provinces and States. In the course of a 

 single " sugar season," which lasts ordinarily from twenty-five to 

 thirty days, a sugar maple two feet in diameter will yield not less 

 than twenty gallons of sap, and sometimes much more.* This, 

 however, is but a trifling proportion of the water abstracted from 

 the earth by the roots during this season ; for all this fluid runs 

 from two or three incisions or auger-holes, so narrow as to inter- 

 cept the current of comparatively few sap vessels, and besides, 

 experience shows that large as is the quantity withdrawn from 

 the circulation, it is relatively too small to affect very sensibly the 

 growth of the tree.f The number of large maple-trees on an 



* Emerson {Trees of Massachusetts, p. 493) mentions a maple six feet in di- 

 ameter, as having yielded a barrel, or thirty-one and a half gallons, of sap in 

 twenty-four hours, and another, the dimensions of which are not stated, as 

 having 3aelded one hundred and seventy-five gallons in the course of the sea- 

 son. The Cultivator, an American agricultural journal, for June, 1842, states 

 that twenty gallons of sap were drawn in eighteen hours from a single maple, 

 two and a half feet in diameter, in the town of Warner, New Hampshire, and 

 the truth of this account has been verified by personal inquiry made in my be- 

 half. This tree was of the original forest growth, and had been left standing 

 when the ground around it was cleared. It was tapped only every other year, 

 and then with six or eight incisions. Dr. WiUiams {History of Vermont, i., p. 

 91) says: "A man much employed in making maple sugar, found that, for 

 twenty-one days together, a maple-tree discharged seven and a half gallons per 

 day." 



An intelligent correspondent, of much experience in the manufacture of 

 maple sugar, writes me that a second-growth maple, of about two feet in di- 

 ameter, standing in open ground, tapped with four incisions, has, for several 

 seasons, generally run eight gallons per day in fair weather. He speaks of a 

 very large tree, from which sixty gallons were drawn in the course of a sea- 

 son, and of another, something more than three feet through, which made 

 forty-two pounds of wet sugar, and must have yielded not less than one hun- 

 dred and fifty gallons. 



t Tapping does not check the growth, but does injure the quality of the 

 wood of maples. The wood of trees often tapped is lighter and less dense 



