HOW WOUNDS HEAL 



125 



FIG. 83 HOPING STILL! 



This oak tree keeps the bark alive around the 

 decaying stub in the "hope" to protect itself from 

 the decay creeping nearer the trunk every year. 



through the bark to 

 the cambium layer, but 

 no deeper, the cut ex- 

 tending parallel with 

 the direction of 

 growth on the trunk 

 and the main limbs. 

 Very large limbs and 

 trunks may have two 

 or three slits made at 

 equal distances from 

 each other. This op- 

 eration is always performed in spring just as growth begins. 

 When made the cuts are scarcely visible, but in a few days 

 their edges will have spread, perhaps half an inch apart. 



Soon new cells will develop 

 from the cambium and the 

 wound be closed with new 

 tissue. In no way does this 

 healing process differ from 

 that following the splitting 

 of bark in forest and other 

 trees. (Compare 99.) 



115. Limb connections 

 with the trunks of trees. 

 Cross sections of tree trunks 

 made at certain points will 

 show how limbs are pro- 

 duced and how they leave 

 records of their develop- 

 ment and decline in case of 

 injury (Fig. 79). When a 

 limb starts while the trunk 

 is small its initial point will 

 be found close to the center 



FIG. 84 MORE THAN THREE- , ,, fr11n l, onrl a it crows 



FOURTHS OF THE TRUNK LOST BY ot the trunk, and as it grows 



DECAY AND BREAKAGE. YET THE . -11 pn 1 ar p- e Tld its 



TREE BEARS APPLES ANNUALLY. lt: W1H enlarge, a n( 



