320 STATE POMOLOGICx\L SOCIETY. 



THE FUiJCTIOXS OF TUE BARK. 



With the view of determining some facts concerning the functions of the 

 bark in connection with the circulation of sap and the growth of wood, many 

 experiments have been undertaken at tjie College during the past two years, 

 and some interesting results obtained. 



In order to learn whether the annual layer of wood upon trees is developed 

 from the outside of the old wood or from the inside of the bark, the following 

 plan, suggested by the interesting experiments of Duhamel more than a century 

 ago, was tried. Vigorous young trees of elm, glaucous willow, and chestnut 

 were selected, Avhich were from two to three inches in diameter. On the 

 thirtieth of May, before any deposition of recent organized tissue was visible, 

 but when the bark was easily separated from the wood, a horizontal incision 

 was made with a sharp knife around each stem, and immediately above this 

 four vertical incisions on the four quarters of the stem about three inches in 

 length. The four strips of bark were then carefully detached from the wood 

 at their lower ends, and a piece of tinned copper, one inch wide, and long 

 enough to reach around the wood and overlap, was adjusted to the trunk. 

 The bark was then replaced and covered tightly with cloth which had been 

 dipped in melted grafting-wax. The trees grew through the season as usual, 

 and after the fall of the leaves the bandages were removed and the results ob- 

 served. 



In all cases the new wood was found to have been deposited from the bark 

 and outside of the metallic band. Examination under the microscope showed 

 that a thin layer of parenchyma, corresponding to the pith of the first year's 

 wood and such as probably unites all the layers of wood in exogenous stems, 

 was formed upon the metal, and outside of this the fibro-vascular tissue, Avhile 

 the medullary rays were as numerous as in the other portions of the layer of 

 wood, and extended directly from the bark to the metal under it, whether 

 examined in a tranverse or a longitudinal section, thus proving that the 

 material did not flow down in an organized condition from above the band. 



THIS QUITE SATISFACTORY RESULT 



demonstrates that the elaborated material formed in the leaves descends 

 altogether outside of the wood, and that the inner bark is the most highly 

 yitalized part of the trunk of a tree and the source of the new layers of wood 

 and bark which are annually produced. 



Much information has also been obtained in regard to the effects of ringing 

 or girdling the trunks and. branches of trees by the removal of a band of bark 

 only, or of bark and sapwood from the entire circumference. 



This has long been practiced in new countries to kill the timber which the 

 settler had not time to fell, but must destroy to obtain grain and other crops. 



THE CHINESE 



are said to produce curious dwarf fruit trees by ringing a fruit-bearing branch 

 and placing over the spot a flower-pot with earth in which roots are developed, 

 so that it may then be detached from the parent tree and cultivated indepen- 

 dently. The Italians propaga*<e the fig tree in a similar manner, and this proc- 

 ess may be made very useful iu securing the certain growth of a sporting 

 branch of any woody plant, or of the branches of species with spongy or pithy 

 wood which will not root from cuttings. It is a well known fact that the 

 ringing of a branch of a vine or tree will tend to increase the size of the fruit 



