870 JOURNAL OF FORESTRY 



a consideration of the particular problems involved in the marking of 

 each sale area. 



■ There are four important fallacies in the old rules which the nev^ 

 ones are designed to avoid : 



(i) Any comparison of the volume of seed trees or other trees to 

 be left to the volume of the original stand. 



There is no necessary relation between the board-foot contents of 

 the trees to be left and their value for seed or for future growth. Their 

 value for either purpose depends upon the size of the crowns, the 

 thriftiness of the trees, their distribution over the area, their wind- 

 firmness, etc. The per cent of volume left is interesting, but is posi- 

 tively detrimental as a guide in marking. A possible exception would 

 be a case of partial cutting where it was important to insure a second 

 cut within a fixed period. 



(2) The idea that groups of seed trees are essential in every case of 

 clear cutting. 



Experience has proven that they are not needed in most cases. 



(3) The reservation of white-pine trees as seed insurance against 

 fire. 



White pine is more susceptible to fire damage than most of the asso- 

 ciated species. In case of fire after reproduction is established (which 

 is expected from seed stored in the duff) it is practically certain that 

 the seed trees would be burned as well as the young trees. Larch and 

 Douglas fir are two very fire-resistant species which usually occur with 

 white pine. For purposes of insurance against fire these species are 

 the only logical ones to reserve. 



(4) A classification of stands based on the age of the timber. 

 There is no relation between the age and size of trees in crowded 



stands. Numerous examples of even-aged mature stands have been 

 found which should properly be handled by a partial cutting because 

 of the very great range in diameters and heights. However, in accord- 

 ance with the old marking rules, the marking of such stands followed 

 the instructions for "mature stands," which prescribed clear cutting 

 with groups and specified not less than 15 per cent of the volume of 

 merchantable trees to be left. Obviously, under such conditions a clear 

 cutting was impossible, and attempts to form groups and to leave 15 

 per cent of the merchantable volume resulted in immediate loss of 

 revenue, eventual loss (through decay) of trees now merchantable and 

 ready to cut, and in no benefits silviculturally which could not be ob- 

 tained in other ways. 



