48 MISC. PUBLICATION 11, U. S. DEPT. OF AGRICULTURE 



further complicated by lack of knowledge of the effect of the two cuttings 

 on the stand. 



In order to get some idea of what the yield from cut-over land might be in 

 50 years, 500 increment borinjis were taken on a mixed stand cut about 45 

 years imo. Tlu> results of this study were then applied to the reserve stand 

 left oil this working circle. 



Table 2 shows the increase in diameter by 2-inch diameter cUisses for a 

 50-year p<'riod. 



Application of these results to the stand and stock tables for the Government 

 laud cut over to date gives the following: 



Volume per acre in board feet 



t „.^^ > ™~r.«» ■ k T««nn» IncremeDt I Volume of i • __-«_« 



Average Amount Araonnt lo-inch note stuff Average 



Cutting cycle orlginBl cut (S4.7 left (15.3 °", h h ^rehant- stand at 



i stand percent) percent) i^p^Mi Sble M«>°<J C"t 



SOyears i 30,700 20,000 4.700 10.000 2.800 17.600 



Under the provisions of this plan it is proposed to leave 20 per cent of the 

 stand and remove SO per cent. Under these conditions the resultant stand at 

 the end of 50 years would be as follows : 



Volume per acre in hoardrfeet at the end of. 50 years 



Increment Volume of 

 on 12-inch pole stutT 



Stand percent) percent) tr.i^',«ft Tble 1 second cut 



Average Amount Amount ^JJ|.T,feh p^leTtulT Average 

 Cutting cycle l original cut (80 left (20 ° h h h .S^«-httnt. s^nd "»» 



Myears } 30,700 24,600 r,, lOO 12,000 2,800 j aO,«» 



The above computations indicate that with a reserve stand of 6,100 per acre 

 a stand of 20,000 or over would be prt»duced in 50 years. This is not con- 

 sidored too much to expect, inasmuch as 90 i)er cent of the trees left are under 

 30 inches d. b. h., and with release from competition and suppression should 

 take on increment rapidly. A cut of 16,000 per acre is therefore considered 

 conservative for the second cutting cycle. 



DISCUSSION OF ROTATION AND CUTTING CYCLES 



Available growth data indicate that on a 100-year rotation a tree of at least 

 18 inches d. b. h. can lie produced. The reproduction under 4 inches d. b. h. now 

 on the ground should, in a 100-year period, be from 24 to 30 inches d. b. h. 

 Figuring that logj,'ing during the second cutting cycle will destroy about one- 

 half of the reproduction, there should be at the end of the lirst rotation a stand 

 one-half stocked with trees from 18 to 30 inches d. h. h., with a small i)ercentage 

 of larger trees left for seeding x»uriioses when the second cut is made. It 

 would therefore seem safe to assume a rotation period of 1(X) years to start 

 with. 



In determining the length of cutting cycles to be adopted the following condi- 

 tions were considered : 



1. A rapid cutting over of the area, removing from 60 to 65 per cent of the 

 volume. First cutting cyck', 35 to 40 years. Second, 00 to 65 years. 



2. A slower cutting over of the area, removing from 80 to 85 per cent of the 

 volume. Cutting cycles, 50 years each. 



Advantages of rapid CM///»r/.— Ucniovrs decadent and part of mature timber 

 in from 35 to 4(i years. Leaves heavier second cut more nearly approaching a 

 sustained-yield basis. 



Disadvantaiics of rapid cutting. — (o) From 15 to 20 per cent of timber left 

 would be of mature and thrifty-mature classes, (h) Marking would be com- 

 plicated, (c) A lighter cut per acre reduces the chance for a profitable opera- 

 tion at present. 



