TABLES RELATING TO PARTS III AND IV 279 



and Washington. In the application of these to standing 

 timber somewhat the same difficulties are met as above, 

 while others arise due to the fact that only a very unusual 

 tree throughout its merchantable length has a true taper. 

 Normal and also unusual relations in northwestern trees 

 are illustrated above. The inference is easy that tables 

 of the kind mentioned are best left to the use of experts. 



The first four of the above sets of figures, for Douglas 

 fir, represent normal form. The body of the tree is seen 

 to have less taper than either the butt log or the top; the 

 larger the tree's diameter the faster the taper normally, 

 and that shows in the butt log particularly. On this last 

 fact rests the practice of cruisers of taking base diameter 

 pretty high usually and frequently discounting the diam- 

 eter ascertained by measure. Their effort really is to 

 line the basal diameter with that at the top of the first 

 log and those above it. 



Trees No. 5 and 6 are representative of quick and slow 

 taper, or what amounts to the same thing, of short and 

 tall timber. On the same base diameter one tree has 

 twice the contents of the other. No. 6 is a tree of very 

 unusual taper, however. 



Other northwestern species, with the exception of 

 cedar, have form in general similar to fir, but a much 

 thinner bark, as Nos. 7 to 10, for hemlock and noble fir, 

 illustrate. Very heavy taper high up in the trees is also 

 shown here. The bearing of this last fact on the appli- 

 cability of a straight-taper volume table is illustrated 

 below from tree No. 10 in the series. (See also discussion on 

 pages 196 and 197.) The error in one case is 3 per cent, the 

 other 15 per cent. This last error is seen to be incurred 

 by inclusion in the reckoning of a log that contains only 

 2 per cent of the volume of the tree, and that likely to be 

 broken up in felling. The practice of commercial cruisers 

 in neglecting the contents of trees above a diameter equal 

 about half the base diameter is thus rationalized. 



Contents of 4 lower logs, actual taper 6880 feet 



Contents of 4 lower logs, regular taper 6660 feet 



Contents of 5 logs, actual taper 7040 feet 



Contents of 5 logs, regular taper 5960 feet 



Contents of fifth log 160 feet 



