FOREST commissioners' REPORT. lOI 



remove the larger trees to a diameter of 7 or 8 inches. Hard 

 and fast rules, however, are seldom applicable, and the diameter 

 limit should be flexible; that is, trees above the limit should be 

 left or trees below the limit removed, as circumstances pre- 

 scribe. 



This method is not applicable to mature or overmature stands, 

 even when these show a wide variation in diameters. In such 

 cases the smaller trees are not younger, but are simply sup- 

 pressed, poorly developed, and usually unthrifty trees of the 

 same age as the rest of the stand. Opening up the stand would 

 not materially increase their rate of growth, and the chances 

 are that they would deterioate or die before the next cutting. 

 Such a stand should be cut clean and all of the merchantable 

 material utilized. 



2. Clean cutting to secure reproduction is applicable in pure, 

 middle-aged stands, in which the trees are nearly all of the same 

 size and in which there is no lower story of other species. Such 

 stands usually have a considerable undergrowth of shrubs and 

 weeds which would interfere with the growth of seedlings, but 

 through which the more vigorous sprouts are able to shoot up 

 and establish a new stand. This second growth may not be as 

 good as the original, but if the system is carefully carried out 

 a sufficiently heavy stand to warrant a second cut is practically 

 assured. 



The cutting should be done when the trees are from 50 to 60 

 years old, at which age they have an average diameter of 8 or 

 9 inches. After this age, the sprouting capacity is feeble or 

 entirely lacking and the reproduction scanty. Also, the rate of 

 growth is then too slow to warrant holding the stand longer, 

 and the amount of heartwood increases rapidly. 



The resulting sprout stands may be managed by the clean- 

 cutting system in the same way. Owing to their shorter life, 

 however, the cutting should take place when the trees are about 

 40 or 50 years old, with an average diameter of 7 or 8 inches. 

 The method can not be continued indefinitely, however, and a 

 second, or under most favorable circumstances a third, crop is 

 all that can be hoped for, owing to the exhaustion of the birch 

 stumps and the encroachment of other species. 



The shape and size of the cuttings are immaterial, and since 

 sprout reproduction is depended on, the leaving of seed trees 

 is unnecessary. There will always be trees enough near by to 



