On the Formation of the Bark of Trees. 4 1 



to it, from the cortical vessels of the principal stem ; and 

 thence, in the event of the death of the lateral branch, it al- 

 ways continues to live. But it not unfrequently happens, 

 that a lateral branch forms a very acute angle with the prin- 

 cipal stem, and, in this case, the bark between them be- 

 comes compressed and inactive ; no pedestal is in conse- 

 quence formed, and the attachment of such a branch to ilie 

 stem becomes extrenielv feeble and insecure*. Instead of 

 the reproduced buds of the preceding experiment, buds were 

 inserted in the foregoing summer, or attached by grafting in 

 the spring; and, when these succeeded, though they w'ere 

 in many instances taken from trees of different species, and 

 even of different ocncra, no sensible difference existed in the 

 vessels, wtiich appeared to diverge into the bark of the stock, 

 ffQjn these buds and from those reproduced in the preceding 

 experiments. 



It appears, therefore, probable, that a pulpous organisablc 

 mass first derives its matter cither from the bark, or the 

 alburnum : and that this matter subsequently forms the new 

 layer of bark ; for, if the vessels had proceeded, as radiclesf, 

 from the inserted buds, or grafts, such vessels would have 

 been, ia some degree, different from the natural vessels of 

 the bark of the stocks ; and il does not appear probable, even 

 without referring to the preceding facts, that vessels should 

 be extended, iu a few days, by parts successively added to 

 their extremities, from the leaves to the extremities of the 

 roots ; which are, in many instances, more than two hun- 

 dred feet distant from eacli other. 1 am, therefore, inclined 

 to believe, that, as the preceding facts seem to indicate, the 



* The advantages, which may be obtaii-ed liy pruning timber trees judi- 

 ciously, appear to be very little known. I have endeavoured to ascertain the 

 practicability of giving to treei such forms as will render their timber more 

 advantageously convertible to naval or other purposes. Tlie success uf the ex- 

 periments on small trees has been complete, and the results perfectly consis- 

 tent, in every case, with the theory I have endeavoured to support in former 

 memoirs; and I am confident that, by appropriate management, the trunks 

 and branches of growing trees may be moulded into the various lorms best 

 adapted to the use of the ship-builder; and that the growth of the trees may 

 at the same lime be rendered considerably more rapid, without any expense 

 or temporary loss to the proprietor. 



t Darwin's Phyiulogia. 



matter, 



