173- 



a) The lower story is left to shift for itself. It 

 receives no care. The uppee story grows rapidly, closes up the openings, 



and practically kills the lower story out by the end of the rotation. 



&4 Advantage: rapid growth in the upper story is ob- 

 tained and therefore a shorter rotation is &&&&&& possible; there is good 

 protection of the site by the upper story and a large amount of firewood 

 is obtainable from the upper story, This form of forest is especially 

 good for pine for improving the site, 



b) The upper story may be thinned out to make room for 

 the under story trees. Both stories are thus oared for together. 



In either case there is always a definite end of the rotation. 

 Vfoen the upper story matures, both stories are cleared off, 



. Method of Light Accretion or Accretion Cutting. 



The Forest Service definition of an accretion cutting 



(or accretion thinning) is: n thinning made specif ically to increase the 

 rate of growth in diameter of the trees which are left standing, 



(1) The accretion cut is an accessory enterprise in the 



clear cut and shelterwood systems tenon it is used at all. It occurs to a 

 leas extent in the selection system. It means a specially severe thinning; 

 and is often classed as a thinning method rather than as a Silvicultural 

 system, as is indicated in the above definition. That is the better term. 

 The stand is opened beyond the point of further closing. The accretion 

 cut gives openings which are beyond the maximum closing by the stand. 



(2) As in the reserve tree system, the site must be cared 

 for by underplantirig. In case the remaining stand, after an accretion cut, 

 consists of but few tree per acre, the method practically becomes the 

 reserve tree method. 



(3) The accretion cut means greater growth, fewer trees, 

 and therefore a larger size of timber obtained, and a shorter rotation 

 is possible. 



Hote: These extra methods: two- story, accretion cutting, etc., are 

 not common; they are not much used except in pine. They are promising for 

 valuable forests of large sized timber. 



The Germane give the Accretion Cut two names: 



1) Lichtungsauwacha: opening for growth. 



2) Lichtungsbetrieb: opening the way of management. 

 These are different meanings for the same system. 



These secondary systems are not so much systems of reproduction 

 ae they are systems of caring for the forest. They apply more to older 

 stands which are nearing maturity. 



7) Coppice System, 



a.. The coppice system has a great variety of forms according 

 to the tirnber~rai0ed and the object in view. 

 Timber: short rotations. 

 Eucalyptus I firewood system. 

 Others for shelter-belts and wind-breaks. 

 Others for tanbark; willows for baskets, etc. 



