WOODY PLANTS 
141 
EXERCISE XLVIIL 
Parts of a Trunk . 
In living trees there grows each year a ring of 
wood between the old wood and the bark, and by 
counting the rings yon can tell the age of the tree. 
Fiq. 235. 
Fig. 235 is a picture of the end of a tree-trunk. A 
dark and light streak, taken together, represent a 
yearly ring of wood. Can you tell how many years 
it was in growing ? When you see saw-logs, find out 
their ages by counting the rings. Observe whether 
these annual layers are always of the same thickness. 
Notice whether the wood of a tree, from the center 
to the circumference, is all of one color. 
