KNOTS AND KNOT-HOLES 



79 



season. Consult the woodpile, and observe the 

 variations in thickness of the annual rings, and 

 especially of the same ring at different places in 

 the circumference. 



We have seen that some of the side branches 

 on the little cherry tree (Fig. 2) died, and 

 that all the others will probably perish. Fig. 70 

 shows a dead limb on an oak tree. The limb 

 became weak because the shade was too dense, 

 and because branches 

 above it took more 

 than their share of 

 food. Finally, borers 



71. A knot hole. 



72. Knot in a hemlock log. 



and fungi attacked it, and it died. It rotted 

 slowly away, year by year its twigs fell, and 

 finally a heavy fall of snow broke it off as we 



