444 



BOARD OF AGRICULTURE. [Pub. Doc. 



Fig.. 3.^ Branch wound liealiiig- well all round. 



in Fig. 2. One reason tliat^ healing usually begins last at 

 the bottom of the wound is, that in the operation of prun- 

 ing the cambium is often- 

 cst injured there. Where 

 nearly circular wounds are 

 skilfully made, in vigor- 

 ous trees, the callus may 

 come readily from all sides 

 of the wound, healing as 

 in Fig. 3. Of 20(3 wounds 

 rnade in 1895, 103 had 

 healed in 1898 on the sides 

 only, 41 had healed all 

 around, 39 on the top and 

 sides only, 3 on the top 

 and one side, 2 at the bottom and both sides, and 1 at 

 the top only. 



If healing progresses only from the sides, it may still 

 cover the wound entirely in time, although it will take 

 3'ears, if the wound is not too large. When 

 the callus meets in the centre of the wound, it 

 grows together, solidifying over the stump. 

 As the callus grows quite rapidly for the first 

 year or two, small wounds will soon become 

 entirely capped over with new wood and bark, 

 thus perfectly sealed in and protected from 

 deca}^, as in Fig. 4. This new growth does 

 not attach itself in any way to the surface of 

 the Avood. If the wound be large, the callus 

 is likely to be checked in its growth after a 

 year or two by the formation of a rigid bark, 

 Avhich covers it and perhai)s prevents further 

 growth. 



Nature's Pruning. 



As young trees grow, many of the newly 

 formed buds perish in the struggle for exist- 

 ence, leaving only a few of the stronger ones to })u.sh out 

 the shoots which will make the future limbs of the tree. 

 In this first thinning, insects play a prominent part, the 



Fig. 4. — Sec- 

 tional view of 

 liealfd branch 

 wound, show- 

 ing covering of 

 new wood and 

 l)ark. 



