by cultivator or wagon liiib, it is interesting to observe bow nature 

 attempts to repair tbe injury. It is about tbe ragged edges of tbe 

 wound tbat new tissues are developed. Tbe wood in tbe center is 

 not immediately covered — in fact, may never be completely 

 enclosed — iMit tbe area is decreased eacb year l)y deposits of new 

 wood about tbe edges. Tbis sbows us tliat tbe life activities of tbe 

 tree are located mainly between tbe bark and tbe new wood. Tbis 



7. — The croiDti and hole of a great Burr Oak near Cornell 



camjyus. IIoic old f 



is tbe vital part. A bealtby condition of bark may be promoted by 

 certain treatments. Tbis and otber matters of like nature will l)e dis- 

 cussed in a succeeding lesson. Have you ever seen a "bide-bound" 

 tree? Top-graft a cberry on a plum stock and watcli tbe result. 



TJie croion. — Tbis is composed of brancbes — wbicli comprise tbe 

 frame-work — twigs, or the small tributaries, and leaves, or tbe 



360 



