124 FARM FORESTRY 



tain thrifty trees with good crowns can be selected for the 

 final stand and the trees around them when they begin to 

 crowd can gradually be thinned out. Heavier thinnings can 

 be made than in the woodlot where trees with long boles are 

 desired. At 40 years of age there should be about 100 trees 

 to the acre and the crowns should completely shade the forest 

 floor. It is seldom that sugar maple forms pure stands. It 

 is usually found in mixture with other trees. Where it is 

 desired to develop a sugar bush these trees should gradually 

 be removed by utilizing them for fuel and other purposes on 

 the farm and their places in the stand filled by planting the 

 sugar maple. 



The sap season begins the middle of March and continues 

 to the third week in April. The season usually lasts about four 

 weeks. Trees vary in the amount of sap they will yield and 

 in the percentage of sugar in the sap. The amount depends 

 on the individual tree, and on the character of the soil and 

 the situation. It fluctuates with night and day and with a 

 change of temperature. Trees average about 12 gallons of 

 sap a year or about 3 pounds of sugar. The amount may be 

 much lower and individual trees have been known to yield 

 75 gallons of sap and to make 30^4 pounds of sugar in a single 

 year. Sap usually contains about 3 per cent of sugar, but 

 it may run as high as 10 per cent. Moderate tapping does 

 not injure the trees or affect the growth or the quality of wood. 

 In tapping a tree the loose bark should be brushed away 

 so that pieces will not fall into the pail. The hole is bored 

 with a ^-inch or a ^-inch bit about an inch deep, directed 

 slightly upward so as to insure drainage. Small holes are used 

 so that they will close over in a year or two. The greater 

 part of the sap comes from the outer 10 to 15 rings of the 

 wood, so that deep boring is unnecessary. Wooden spouts 

 are used, made from elder or sumach, the pith being forced 

 out with a stick or burned out with a hot iron. The pails for 

 collecting the sap should be covered to keep out bark, dirt, 



