98 A MANUAL OF FORESTRY 



three to live feet above ground. Then, after the trees are felled, 

 inspection of the stumps shows whether they were marked for 

 removal. 



I f axe blazes are used for marks it is well to have a distinctive 

 stamp on the head of the axe and stamp each blaze, thus pre- 

 venting marking by unauthorized parties. 



Pruning. Pruning as used in forestry really should be classed 

 as a type of intermediate cutting, for its purpose is to improve 

 the quality of the crop. It is an operation which as yet has 

 been little used, and will be used only in occasional cases, where 

 forest management can be on a highly intensive scale, and with 

 certain species, like white pine, in which natural pruning is poor, 

 even when grown in a crowded stand. 



Pruning should only be practiced where clear lumber is wanted, 

 and where such lumber is sufficiently valuable to pay the cost 

 of the operation. The way in which pruning raises the value of 

 the forest crop is through the early removal of lower limbs, 

 allowing the production of clear lumber free from knots. (See 

 Fig. 40.) 



Forest pruning usually is restricted to the removal of dead 

 limbs. There are two reasons why the removal of live limbs is 

 bad; first, because the wounds left by the pruning of live limbs 

 offer good opportunities for the entrance of fungi or insects, and 

 second, because the removal of live limbs disturbs the balance 

 between the crown and root systems of the tree, and may often 

 result in retarding its growth. It is claimed, also, that in the 

 case of some species pruning of live limbs causes loose knots in 

 the timber. A few of the lower live limbs often can be removed 

 without appreciable injury to the tree. 



It is impracticable to prune higher than the first log length, 

 or as high as a man can reach with his pruning tools. Pruning 

 should be done at the earliest possible moment, as soon as the 

 branches have died for the distance up the trunk that the trim- 

 ming is to be done. In this way there will be a smaller knotty 

 center inside the log. The pruning can ordinarily be done before 

 the trees become twenty years of age. 



