INTRODUCTION. 3 
if trees may be compared to the columns which support the 
portico of a temple, shrubs may be considered as the statues 
which surmount its pediment, and as the sculptures which orna- 
ment its frieze. 
It is not to be wondered at, that trees and shrubs should have 
excited the attention of mankind in all civilised countries, and 
that our accumulated experience respecting them should be con- 
siderable. The first characteristic instinct of civilised society is, 
to improve the natural productions by which we are surrounded ; 
and the next is, by commerce to appropriate and establish in our 
own country the productions of others, while we give our own 
productions in exchange ; and, thus, the tendency of all improve- 
ment seems to be to the equalisation of enjoyment, as well as to 
its increase. 
Notwithstanding the use, the grandeur, and the beauty of 
timber trees, it is a fact, that, compared with herbaceous vege- 
tables, the number of species distributed over the globe is com- 
paratively smal]. The palms, the banana, the pine-apple, and 
other plants, popularly or botanically considered as trees or 
shrubs, though some of them attain a great height and thickness, 
are, with very few exceptions, of no use as timber. Almost all 
the timber trees of the world, with the exception of the bamboo, 
belong to what botanists denominate the dicotyledonous division 
of vegetables ; and, perhaps, there are not a thousand genera of 
this division on the face of the earth which afford timber trees 
exceeding 30 ft.in height. ‘The greater part of these genera, 
supposing such a number to exist, must belong to warm climates ; 
for in the temperate zones, and in the regions of warm countries 
rendered temperate by their elevation, the number of genera 
containing timber trees 30 ft. in height, as far as hitherto dis- 
covered, does not amount to a hundred. The truth is, that 
between the tropics the greater number of species are ligneous, 
while in the temperate regions there are comparatively few, and 
in the frozen zone scarcely any. It may naturally be expected, 
therefore, that, in the temperate regions, there should only be a 
few timber trees which are indigenous to each particular country. 
In Britain, for example, there are not above a dozen genera of 
trees, furnishing in all about thirty species, which attain a height 
exceeding 30 ft. ; but there are other countries of similar climates, 
all over the world, which furnish other genera and species, to 
what is, at present, an unknown extent; and it is the beautiful 
work of civilisation, of patriotism, and of adventure, first, to col- 
lect these all into our own-country, and next, to distribute them 
into others. While Britain, therefore, not only enjoys the trees 
of the rest of Europe, of North America, of the mountains of 
South America, of India, and of China, she distributes her own 
trees, and those which she has appropriated, to each of these 
*B 3 
