THE NORTHERN HARDWOODS REGION 279 



Many of the second-growth stands in the type are even-aged 

 in nature. Where such stands are well situated with reference 

 to markets they can be handled on the shelterwood system, and 

 thinned at regular intervals during the rotation. An excellent 

 grade of cord wood can be secured from these thinnings. 



The length of rotation for the hardwood type must be at least 

 seventy to one hundred years. It is only with the faster growing 

 species such as white ash, basswood, and red oak that a seventy- 

 year rotation can be used. The slower growing hardwoods 

 require one hundred years or more to reach maturity. 



Where the stand is pure sugar maple, or contains a consider- 

 able per cent of this species, it may often be desirable to handle 

 the type as a sugar orchard for the production of maple sugar 

 and syrup. To accomplish this somewhat different treatment 

 is required from that given the type when timber production is 

 the aim. Pure stands of maple are wanted in this case and in 

 all the cuttings other species should be removed, favoring the 

 maple and encouraging it to seed all openings. The amount 

 of sap secured from a maple tree is proportional to the size of 

 the crown, i.e., to the leaf surface. Bearing this in mind, it 

 might appear as though the aim should be to encourage the 

 development of a very few broad spreading trees, possibly three 

 or four to the acre. This would be going to an extreme. For 

 what is really wanted is the greatest amount of sap production 

 from a given area. This will not necessarily be secured from a 

 very few large trees, but rather from a number of moderate sized 

 trees so spaced that the greatest amount of leaf surface is de- 

 veloped. Tall trees, fairly slender for their height, but with 

 dense crowns which nearly reach the ground, represent the ideal, 

 which calls for a sacrifice of the clear length of the bole, so 

 desirable in a timber tree. 



The chief difference in handling for sap production as against 

 lumber production is that in the former a tree with the longest 

 possible crown is wanted, while for the latter a tree with the 

 longest possible clear length is desired. 



Wherever the stand approaches an even-aged form thinnings 



