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 
