One reason why so many classifications have come into use is that none of them is quite accurate. A better one will be explained later. See [p. 23].

As in the study of all woods three sections are made, it is well at the outset to understand clearly what these are.

The sections of a tree made for its study are (Fig. 3):

(1) Transverse, a plane at right angles to the organic axis.

(2) Radial, a longitudinal plane, including the organic axis.

Fig. 3.

A.B.
A, B, C, D, Transverse Section.
B, D, E, F, Radial Section.
G, H, I, J, Tangential Section.
A, B, C, Transverse Section.
A, B, D, E, Radial Section.
B, C, E, F, Tangential Section.

(3) Tangential, a longitudinal plane not including the organic axis.