1S2 SAP OF SUGAR MAPLE. 



acre is frequently not less tlian fifty,* and of course tlie quantity 

 of moisture abstracted from the soil by this tree alone is measured 

 by thousands of gallons to the acre. The sugar orchards, as they 

 are called, contain also many young maples too small for tapping, 

 and numerous other trees — two of which, at least, the black birch, 

 Betula lenta, and yellow birch, Betula excelsa^ both very com- 

 mon in the same climate, are far more abundant in sap than the 

 maple f — are scattered among the sugar-trees ; for the ISTorth Am- 

 erican native forests are remarkable for the mixture of their crops. 



The sap of the maple, and of other trees with deciduous leaves 

 which grow in the same climate, flows most freely in the early 

 spring, and especially in clear weather, when the nights are frosty 

 and the days warm ; for it is then that the melting snows supply 

 the earth with moisture in the justest proportion, and that the 

 absorbent power of the roots is stimulated to its highest activity. 



When the buds are ready to burst, and the green leaves begin 

 to show themselves beneath their scaly covering, the ground has 

 become drier, the absorption by the roots is diminished, and the 

 sap, being immediately employed in the formation of the fohage, 

 can be extracted from the stem in only small quantities. 



than that of trees which have not been tapped, and gives less heat in burning. 

 No difference has been observed in the bursting of the buds of tapped and un- 

 tapped trees. 



* Dr. Rush, in a letter to Jefferson, states the number of maples fit for tap- 

 ping on an acre at from thirty to fifty. " This," observes my correspondent, 

 " is correct with regard to the original growth, which is always more or less 

 intermixed with other trees ; but in second growth, composed of maples alone, 

 the number greatly exceeds this. I have had the maples on a quarter of an 

 acre, which I thought about an average of second-growth ' maple orchards,' 

 counted. The number was found to be fifty-two, of which thirty-two were 

 ten inches or more in diameter, and, of course, large enough to tap. This 

 gives two hundred and eight trees to the acre, one hundred and twenty-eight 

 of which were of proper size for tapping." 



f The correspondent already referred to informs me that a black birch, 

 tapped about noon with two incisions, was found the next morning to have 

 yielded sixteen gallons. Dr. Williams {History of Vermont, i., p. 91) says: 

 "A large birch, tapped in the spring, ran at the rate of five gallons an hour 

 when first tapped. Eight or nine days after, it was found to run at the rate 

 of about two and a half gallons an hour, and at the end of fifteen days the 

 discharge continued in nearly the same quantity. The sap continued to flow 

 for four or five weeks, and it was the opinion of the observers that it must 

 liave yielded as much as sixty barrels [1,890 gallons]." 



