106 
SEASONING. SOFTWOODS. HARDWOODS. 
sap in froth and steam at the two ends. It is the great facility with which moistuie 
escapes along the grain of the wood that causes the unequal shimkage and 
troublesome cracks that occur at the ends of logs and planks in the hush and m the 
timber yards. 
In this connection, however, we must remember that the timber supplies of the 
world are derived from two great and widely diverse groups of trees. The fi?st 
group comprises the Coniferae, of which there are said to be 44 genera and 480 
species. The constituent cells in the wood of this group have thin walls, and the 
wood as a whole is consequently capable of readily dispersing its natural sap by 
evaporation. Abundant resin may make the heartwood or duramen dense and even 
heavy; but it does not greatly interfere with the radiation of moisture from the 
log or from the sawn product. The seasoning of such wood presents no serious 
difficulty. All conifer timbers are called softwoods; but consistently with this a 
sub-distinction is now made between the harder and softer species of Pinus. 
The second great group of timber-yielders also includes many genera and 
species. Eminent amongst them are the Oaks, the JValnuts and Hickories, the 
Ashes and Maples, the Planes, the Acacias, and the Eucalypts with their close 
kindred the Tristanias, the Syncarpias, and the Angophoras. These all yield 
woods that are dense and heavy; and the laboratory explains why the wood as a 
whole is of this character by showing that the constituent cells, and tubes, and fibres 
are thick-walled with cavities often wholly closed where the wood is mature. Such 
woods yield their moisture slowly, and are liable to serious deterioration if badly 
handled between the stump and the workshop. The eucalypts especially require 
great care and skill; and their value merits all we can bestow. 
When we make leather out of the skin of an animal we kill the animal and 
alter the condition of the skin by tanning. When we make timber out of a living tree 
we kill the tree and change the condition of the wood by sawing and seasoning. 
Merely drying the water out of a log or plank is not seasoning it. The water has 
to be evaporated without injuriously altering the structure and form of the wood. 
We season wood when we so dry it and harden it that it does not crack, or warp, 
or shrink irregularly, or become brittle. Evaporation must be facilitated and 
equalized and regulated for as many weeks or months or years as may be required 
to complete the desired changes. Beginning with the bole of the tree as soon as 
it falls, we must strip the bark off to encourage radiation of moisture all over the 
surface and check it at the ends of the logs as they are sawn off. Temporary 
covering of the ends of the logs with sawdust or soil may also be desirable; but 
experts warn us against keeping them covered very long lest decay should set in. 
Where Eucalyptus logs are from mature trees and consist almost entirely of 
heartwood they may he allowed to he for some time before they are sawn up; but 
when the milling is in progress there must be no delay in disposing of the sawn 
product in some way that will protect it from cracking and warping. Prompt 
stacking in some approved method is always necessary with sawn Eucalyptus 
timber. Where large sheds and artificial heat are not available the old method of 
sorting the boards and scantling into nearly horizontal stacks with narrow battens 
between is perhaps still the best. The timbers are placed even and very carefully 
battened at the slightly higher end. Such a stack can be built up to a great height 
