84 



NATURAL REGENERATION 



forester to have in mind the normal or average local number of trees per 

 acre for the different diameter classes; then by a comparison of the normal 

 with the actiial stand it can be determined whether the forest has too 

 many or too few trees of the different dxe classes. Such data would be a 

 gvide to determine from what diameter classes in a selection forest trees 

 should preferably be cut. The following table, compiled by Huffel, 

 shows average figures per acre for fir ia different regions. 



« SmaUer trees are not calipo^d. 



Schaeffer ' gives the following formula for the management of a 

 selection forest: 



"1. Establish a curve of a normal high forest, as has been indicated (see p. 214) 

 according to the pyi.'it.ing stand. 



"2. Calculate the yield by any method (if you wish, even by the mmiiber of trees), 

 provided it is simple, taking care to adopt a figure less than the Tna-ri mnin yidd which 

 has been determined. 



" 3. First cut the over-stocked age classes. 



"4. Arrange for periodic stocktaking in order to revise the yield and to make sure 

 that it approaches the type of forest desired." 



Spruce Selection Fellings. — Contrary to fir forests it is rare that ad- 

 vance growth is found under the parent spruce stand. Therefore, selec- 

 tion by groups or holes is always necessary, since it assures the regenera- 



» Un TyiK! de Futaie JardinSe, S. F. de F. C. et B., A. S. 



