ON THE ELIGIBILITY OF DECORTICATING TREES. 
415 
exposed to the air, is much more dense, and becomes what is called the 
cuticle, and the green cellular part within is the epidermis. The cuticle 
acts as a protection to the living membrane within, and in its vascular 
interior the sap-ducts are embedded. So long as these ducts serve for 
the conduction of the sap, they are useful to the system; and were 
they destroyed while serviceable, the tree would suffer injury; but as 
soon as they are superseded in their functions by the new tubes annu¬ 
ally formed within, and become dry and hardened, they are useful no 
longer, either as channels or as a covering. 
That old hardened bark is useless as a protective covering, may be 
inferred from the circumstance that the first shoot from the seed, and 
all young shoots subsequently produced by the tree, have only one 
cuticle and epidermis, both very thin ; and yet the internal organisation 
is not hurt by cold air or other change of weather. And it appears from 
what has occurred by accident, or proved by experience, that two, or at 
most three, of the latest-formed layers of liber left on the alburnum (the 
last-formed layer of wood) is amply sufficient to carry on the processes 
of growth, and even with increased vigour. This (without trusting to 
the reports of the amateur decorticators) is very apparent, if we examine 
any part of a stem which has been previously wounded and afterwards 
healed over. The scar is always more protuberant than the sound part, 
showing plainly that the living membrane found relief by the removal 
of the old coat of bark. The same effect may be observed on the wounds 
made by silly persons carving their initials or names on the smooth bark 
of healthy trees ; the cicatrices are not only filled up, but become pro¬ 
tuberant, and remain visibly so for many years afterward. 
A very striking instance of the advantage of decortication of even 
healthy trees, once came under the writer’s notice, which he may be 
excused for relating ; it was as follows :— 
Two fine young beech trees, standing, near together, and forming a 
fine feature from the breakfast-room windows of a mansion, were both, 
and cleverly, circumcised, and deprived of perfect rings of bark by 
mischievous boys, to make baskets to hold wild strawberries, then 
beginning to ripen in the woods. The wounds were full six inches in 
length, so that perfect cylinders of that dimension were extracted. The 
scars were conspicuously visible at a considerable distance, and to the 
eyes of those who owned and valued the trees, and who considered the 
wounds as mortal. Although this happened on a Sunday morning, the 
trees were put immediately under the surgical care of the gardener, who 
applied a thick plaster of grafting-clay, binding it on with canvass, and 
fenced the trees from cattle. In two years the wounds were completely 
healed over; and in two years more were, and continue to this day to 
