25 



favor other species with a good prospective value. These latter may 

 have been overtopped by the undesirable ones. 



Liberation Cuttings are operations in immature stands in which 

 the main crop of trees is overtopped by scattered older trees with 

 very wide-spreading crowns. These older trees with present but 

 little prospective value retard the development of a great number of 

 younger trees with good prospective value. The removal of the 

 larger trees is known as a Liberation Cutting. 



Thinnings are cutting operations in immature stands for the pur- 

 pose of accelerating the growth of individual trees and, as a con- 

 sequence, increasing the total yield and improving the quality of the 

 product. Thinnings result not only in a larger quantity and quality 

 increment but aim to improve the appearance and health of the forest. 

 They decrease the danger from fire since a large amount of inflam- 

 mable debris is removed. If thinnings are conducted properly the 

 remaining trees are usually more windfirm. Thinnings also enable 

 one to get returns upon a forest investment without waiting until the 

 crop is finally harvested. Today, under our crude method of regu- 

 lating the returns from our forests, the thinnings or intermediate 

 yield play a minor role, while the final yield comprises practically 

 the total yield ; but as our methods are developed and perfected, the 

 intermediate yields will comprise as in the intensively managed for- 

 ests of Germany, 25%, and later, 50% of the total yield. All forest 

 owners should aim to improve their forest stands by thinning them 

 properly so that they will become more attractive, more sanitary, 

 and more productive. This may be accomplished by thinning early, 

 regularly, and with increasing intensity, but always cautiously, so 

 that the fertility of the soil will be conserved and all available food 

 properly utilized. 



Damage Cuttings comprise operations which remove all damaged 

 material from the forest. The damage may be caused by wind, light- 

 ning, snow, insects, fungi, fire, or any of the many other agents which 

 operate in the forest. Damage cuttings should be made as soon as 

 possible after the damage is done not only in order to utilize the ma- 

 terial before it depreciates too much in value, but also to prevent 

 the spread of such destructive agents as insects and fungi. 



Pruning is an expensive operation and consists mainly in cutting 

 off the lower branches of trees where they were not pruned natur- 

 ally, in order to produce stems with as few knots as possible and at 

 the same time increase the beauty of the stand. 



Underplanting is an intensive cultural operation which is practiced 

 only under systems of intensive management of the forest. It may 

 aim to conserve or even improve the soil or to establish advance 

 reproduction. The aesthetic value of underplanting is also a valu- 

 able asset in developing our forest. 



