266 



BURSTING THE BARK IN CHERRY TREES. 



in the west, the Heart cherry is grown 

 without trouble, be that growth moderate or 

 luxuriant. 



It appears to me that trees of verv vigor- 

 ous growth and full habit, are more fre- 

 quently injured in this way than those of 

 moderate growth ; but debility, no less than 

 luxuriance, increases liability to harm. It 

 would seem to me more logical to term both 

 the one and the other, conditions of suscep- 

 tibility to injury, rather than causes there- 

 of. This, however, is a matter of little im- 

 portance, and may seem a " drawing of dis- 

 tinctions where no difference exists." 



. To proceed with the theories of the two 

 gentlemen ; and first, with Professor Tur- 

 ner's. I think that of all the trees in the 

 forest, field or garden, the vigorous grower 

 would be the last to turn " felo de se," by 

 bursting its own bark by its own agency ; 

 and that the Professor's reasoning on this 

 point is founded in error. This will be 

 made manifest by a recurrence to first prin- 

 ciples. The trunk of the young tree, at 

 birth, is composed of the arch work of the 

 pith, which gives to it rotundity, and holds 

 its fluids in suspension as a sponge — of the 

 medullary sheath, the parenchyma, and the 

 "outer-ring-bark," or epidermis, all cellular 

 tissue, and composed of medullary matter. 

 As soon as woody fibre is formed in a cylin- 

 drical mass around the medullary sheath, 

 the whole cylinder seems divided into a 

 number of nearly equal sections, by radii of 

 medullary matter, running from the cir- 

 cumference toward the centre, and commu- 

 nicating with the medullary sheath. Upon 

 the outer arc of each of these subdivisions, 

 or sections of the woody fibre, rest the bark 

 vessels, as upon a base, — they running lon- 

 gitudinally up and down the trunk on each 

 subdivision, in form of a triangular prism ; 

 each pair of prisms of bark vessels upon 

 adjacent arcs, being separated only by the 



same medullary ray. So that the skeleton 

 of the trunk of a young tree (as is seen at a 

 glance by culling a free grower, as the 

 cherry, peach or linden,) resembles a fluted 

 column ; the interstices between the flutes 

 of which are filled with fleshy matter, as it 

 were, issuing from the medullary ray. It is 

 thus plain, that there are as many sutures 

 in the live bark of a tree as there are medul- 

 lary rays. During the growing season, the 

 flow of sap acts as a solvent upon the me- 

 dullary matter, holding the edges of these 

 sutures in contact ; and the annual growth 

 of woody fibre serves as a propelling power- 

 to open these sutures, and expand the 

 bark. Surely, then, the greater flow of 

 sap must furnish the better solvent, and the 

 larger annual growth the more efficient ex- 

 pansive force. 



That the "outer-ring-bark" does expand, 

 and that freely, upon a thrifty tree, up to 

 the time when the bark naturally changes 

 its character, (the change coming upon most 

 trees about the time they begin to form 

 heart wood,) is a truth I think very obvious. 

 Such a tree has a smooth, glossy, almost 

 transparent epidermis, or outer-ring-bark ; 

 and if we examine it closely in the growing 

 season, it will be found that the expansion 

 is so rapid as to rupture the bark ; and num- 

 berless little interstices will be formed, 

 through which the white fleshy substance, 

 uniting the sutures in the bark, immediately 

 issues, and being hardened by exposure to 

 the air, closes each interstice. Hence, we 

 often see the trunk of the thrifty cherry, or 

 peach, look as though penciled with num- 

 berless horizontal white lines, of an infinite 

 variety of lengths. 



It is your starveling, in both the animal 

 and vegetable kingdom, whose skin thick- 

 ens and grows rigid ; and I believe that 

 "bark-bind," like yellows, in the peach 

 tree, is a consequence, and not a forerun* 



