Observations on the nature, longevity and size of trees / by Alexander Harvey.

  • Harvey, Alexander, 1811-1889.
Date:
[1847]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the nature, longevity and size of trees / by Alexander Harvey. Source: Wellcome Collection.

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    ceases to be, and never afterwards becomes, the seat of any vital action. And if this be conceded, it will probably be allowed also, that the view which has here been taken of the nature and of the natural longevity and size of trees is well-founded; that is to say, that a tree is simply a collection of annual plants of the same species, the production of a series of suc¬ cessive years,—the individual plants of each year shooting up in spring from buds adherent to the persistent dead re¬ mains of the plants of the previous year, growing as parasites on these remains, putting on the characters of old age in autumn, and speedily thereafter dying, having made provision, however, in summer, in the form of buds, for the reproduction of similar plants the following year. And that being thus evolved, and thus growing from year to year, and having no natural limit to their increase and aggregation, there is no natural limit to the age or to the size to which the tree col¬ lectively formed by them may reach. The statement repeatedly made, that the persistent dead remains of the plants of the previous year serve as a mechani¬ cal support to the plants of the following year, does not appear to require any explanation. With regard to the other state¬ ment, that they serve as a temporary soil to these plants, it may be observed, that the buds are always placed in intimate connection with the pith or medutta of the shoots to which they are adherent, and that the pith is soft and juicy in spring, but in the course of the season becomes dry and shrivelled. According to M. Thouars, the buds vegetate in the first in¬ stance at the expense of the pith, deriving from it the ma¬ terials of their development in spring. When this supply of nourishment is exhausted, or at least when the buds send out their own proper roots, ^. e., the fibres formerly mentioned, which, by their interlacement form the woody layer, another supply is provided in the succulent cambium into which those fibres pass, and along which they descend to the soil. From this, of course, is ultimately derived the materials, or a part of the materials, necessary for the growth of the young plants emanating from the buds.
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