VOLUME INCREMENT ON CUT-OVER PULPWOOD LANDS Oi;] 



lead to excessive division of the data, which, besides adding to the 

 cost, will reduce the accuracy of the results. 



Stand Tables. — The caliper record will set the limit upon division 

 of data, since it must cover sufficient acreage in each type and site 

 division to give an even gradation of numbers in the stand table with- 

 out resort to curves to even off the irregularities. Softwoods should 

 be calipered at least to the next inch class lower than that covered by 

 the borings. The limit will depend on the rapidity of growth of the 

 smaller size classes. It is essential that the stand table, in a study of 

 pulpwood species, shall show the numbers in all inch classes down to 

 the size counted as advanced growth and reproduction, though the 

 lower diameter classes may be recorded from a smaller percentage of 

 the total area. 



Volume Tables. — In the absence of volume growth tables based on 

 complete stem analyses, volume tables are essential for the computa- 

 tion of yield. They should be constructed on the basis of diameter 

 alone on the area studied or otherwise should be checked by hyp- 

 someter measurements from volume tables based on both height and 

 diameter. Total volume in cubic feet offers the best medium for 

 comparison of results in pulpwood species. 



Mortality Record. — The destruction of trees left after a logging 

 operation, by various natural agencies, has been commonly observed, 

 and is accepted as unavoidable to a certain extent. Little effort has 

 been made to take account of this loss, which has been largely under- 

 rated. Other mortality than that of healthy trees windthrown, such 

 as those gradually dying by decay, insect attack and exposure, cannot 

 be accurately judged even if under constant observation. Mortality 

 offsets growth, and is quite largely responsible for the undervaluation 

 of cut-over .pulpwood land, since growth will. eventually exceed the 

 mortality and produce a rapid net increment. 



A sufficiently accurate estimate of mortality since a cutting operation 

 can be made by comparing the rate of decay in killed timber with that 

 in slash left by the logging operation. In this way the loss for the 

 first decade may be determined, and the second decade following a 

 logging operation will usually show less down timber than the first 

 decade, due to stabilization of the remaining stand. The study of cut- 

 over lands in the Algoma district of Ontario showed a mortality in 

 ten years nearly equal to the cut. Its causes were chiefly the decay 



