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90 THE WOODSMAN’S HANDBOOK, 
wide strips whenever possible. A strip of 8 rods is always possible. 
The trees upon this strip would all be counted, but on a very wide 
strip the diameters of only a portion might be tallied. The num- 
ber tallied should always be equivalent to the stand on a 4-rod 
strip. Heights would be tallied with the diameter, or, if it is 
sufficiently accurate, may be averaged. Where it is more con- 
venient and time must be saved the system of using plots is best, 
either circular or rectangular, and spaced at definite distances. 
Here either the trees may be counted or the diameters of all of 
the trees on the plots tallied. The selection of sample plots here 
and there should be leit only to persons of exceptionally good 
judgment and long training. 
Only the most experienced timber cruisers may dipense with 
both volume tables and a tally of the sizes of the trees, and obtain 
their results directly by counting and by averaging the contents 
of the logs or the trees in the stand. 
GROWTH OF TREES. 
Since there is a marked tendency among timber-land owners to 
cut their timber with an eye to the future, some knowledge of the 
growth of forest trees becomes important. 
Trees grow by adding each year a layer of wood underneath the 
bark. Since each year contains only one growing season and the 
spring and summer part of this layer are not alike, each year’s 
growth, layer, or ‘“‘annual ring” usually is distinguishable. The 
central fact of tree growth is that each ring means a year. The 
exceptions to this are not important enough to merit notice here. 
DIAMETER GROWTH. 
Some trees grow so slowly that a hand lens is necessary to 
clearly distinguish the rings, others may have rings a half inch in 
width. In any case, a little eee improves the ability to note 
all the rings. 
To find the age of a felled tree at any section, then, requires 
only the accurate counting of the rings. The total age of the tree 
is shown by the total number of rings at the ground; or the total 
number of rings on the stump plus the number of years required 
