KNOTS AND KNOT-HOLES 



23 



22. A hemlock log, split lengthwise, is drawn 

 in Fig. 20. A knot extends to the center. This 

 knot is the remains of a limb, and is nearly as old 

 as the trunk, because it starts from the very cen- 

 ter ; that is, the limb sprung off when the tree 

 was a mere sapling. The probability is that it is 

 just one year younger 

 than the trunk, for 

 we have seen (6) that 

 branches start only on 

 the second year's wood, 

 unless some stress of cir- 

 cumstances starts out the 

 older and dormant buds. 

 The limb finally died and 

 broke off, and the stub 

 was buried. The tissue 

 has now grown out to 

 the end of the stub, and 

 nothing remains but to 

 close over the hole. If the limb had rotted away, 

 a squirrel or a woodpecker might have taken up 

 his quarters in the cavity. The woodchopper, how- 

 ever, found only a knot; and a board sawed from 

 the log would have had a knot whenever the saw 

 cut across the old stub. If the knot were loose, 

 it would fall out, and the board would have had a 

 knot-hole. Knots and knot-holes in boards, therefore. 



Fig. 22. 

 Proper cutting of a. branch. 



