22 Forestry Quarterly. 



selection forest, one can usually make definite progress toward 

 normality, one of the elements in regulation, and the main one 

 so far as that particular stand in concerned. 



At present the material cut in timber sales is prescribed chiefly 

 in cultural, or marking, rules. Since these are discussed in "The 

 National Forest Manual, Timber Sales", (p. 45-48) it is assumed 

 that foresters are familiar with them. They very properly specify 

 the removal of "all mature and overmature trees, except when re- 

 quired for seed or protection. Similarly, all trees which show 

 defects — will be marked", provided at least one merchantable log 

 from the tree can be obtained. A flexible diameter limit may be 

 given, but no instructions are given for determining it. 



The domain of forest regulation, however, is entered a short 

 distance when in "The Manual" the rules specify "as far as type 

 conditions permit, the marking should leave on the ground 

 sufiicient timber for a second cut within a period of 50 years or 

 less"; and again (p. 13) when it states, "Where no working plan 

 exists, the maximum, cut will be based upon the most accurate 

 estimate of merchantable timber, assuming a rotation based on the 

 best available growth data" ; and in Regulation S-2, "The Secre- 

 tary of Agriculture will prescribe each year, upon data and infor- 

 mation furnished by the Forester, the maximum amount of dead, 

 matured, and large-growth timber that may be cut on each 

 National Forest". No edition of the "Use Book", the forerunner 

 of "The Manual", mentions regulating the cutting except that 

 sales may be made up to the capacity of the Forest. 



Instructions for marking timber of dififerent types in various 

 administrative districts have recently been issued, as, for example, 

 "Instructions for Alarking Timber in the Yellow Pine Region in 

 District VI". In the latter, it is prescribed that the type shall be 

 managed 1 ly the selection system or modification of it : that the 

 decadent trees shall be cut together with the thoroughly mature 

 ones and those that will not survive 60 years until the next 

 period of return; that a n'ell distributed stand of thrifty saplings, 

 poles, and young standards shall be left ; and that from 20 to 25 

 per cent, of the estimated volume of trees over 12 inches in 

 diameter shall be reserved. It is planned that the exploitable 

 age, or rotation, of the species shall be 180 years. 



These cultural rules are now mingled with those aimed at 



