8 
TIMBER 
quickly dies, as it can derive no further nourishment from 
the soil. Although absolutely necessary to the growing 
tree, sapwood is objectionable to the timber user, as it is 
the first part to decay. What is called the pith was once 
the seedling tree, and in many of the pines and firs, 
especially after they have been seasoning for a good while, 
this is distinctly noticeable in the centre of the tree, and 
detaches itself from the surrounding wood. 
On looking at the cross section of most timbers of 
commerce we see what are called the annual rings, repre- 
senting generally a year's growth; these are especially 
clear and distinct in the pines and firs, and are approxi- 
mately circular ; they form the pleasing patterns noticeable 
on boards. Figs. 1 and 2. It will be seen that they consist 
of alternate Hght and dark bands gradually shading into one 
another, or dark lines with a light coloured space between ; 
the distance apart of the rings tells us whether the trees 
are of quick or slow growth, those with rings far apart 
generally indicate quick growing timber, those with rings 
close together a timber of slow growth, but even in trees 
Annual 
Rings 
SPRING WOOD 
SUMMER V^OOO 
Fig. 1. — Pine Timber. 
