220 SCIENCE OF THE STUDY OF TREES. PART Il. 
relation in which trees and shrubs stand to man. It is not our intention to 
enter farther into these subjects here, than may be necessary to show to what 
circumstances, in the economical history of trees, we ought chiefly to direct 
our attention, in composing the history of each particular species. The 
subject may be divided into two sections. 
Sect. I. Trees and Shrubs considered with Reference to uncultivated 
Nature. 
Ir appears highly probable, that the greater part of the surface of our globe 
has been, at one time, covered with wood; because, among other reasons, coal 
is found in almost all countries; at all events, it is certain that this has been 
the case with the greater part of the temperate regions of the world at no very 
distant period. North America was, till lately, almost entirely covered with 
trees and shrubs, and presented few naked surfaces, except those of the allu- 
vial deposits on the banks of its larger rivers; and what was so recently the 
state of America must, we may reasonably suppose, have once, at least, been 
that of every other part of the world. 
The influence which a predominance of forest must have in a country 
uninhabited by man must have extended to the animals, the herbaceous 
vegetables, the soil, the waters, and the climate. To wild animals of every 
kind, especially to those of the more ferocious description, forests have, in all 
countries, furnished shelter, and, in a great measure, food : birds, insects, and 
reptiles are the more common inhabitants of forest scenery. Herbaceous 
plants are, for the most part, destroyed by dense forests ; but some kinds, such 
as epiphytal lichens, mosses, and, in some cases, Orchidez, are encouraged by 
the thickness of the shade, and the moist heat which prevails among the trunks 
and branches of the trees. But the great influence of forest scenery in a wild 
state is on the soil; and, in this point of view, natural forests may be regarded 
as a provision of nature for preparing the earth’s surface for the cultivation of 
corn, and of the other plants which constitute the food of man, and of domestic 
animals. It is unnecessary to show how the soil is furnished with that organised 
matter, on which alone perfect plants can live, by the decay of leaves, and, 
ultimately, by the decay of trunks and branches. The waters of a country, 
the rivers and lakes, are necessarily affected by the state of the woods of that 
country. These woods must, in all cases, act more or less as a sponge in 
retaining the water which falls on them; and water must thus be supplied 
more gradually to the rivers, in countries covered with wood, than in countries 
which are cleared, and regularly drained. The influence of forest scenery in 
increasing the moisture of the atmosphere, and in preventing a climate from 
being so hot in summer, and so cold in winter, as it would otherwise be, is 
well understood, and, in such a slight outline as the present, requires only to 
be mentioned. 
The use of studying the influence of trees in an uncultivated country is, to 
afford useful hints with reference to the planting or thinning of them in 
countries which are civilised. That which takes effect on a grand scale, where 
forests cover many thousand acres, must operate more or less in the same 
manner where they extend only to hundreds, or even tens, of acres; and, con- 
sequently, this influence must be kept in view in the formation of plantations, 
both useful and ornamental. If the forests and plantations of Britain are no 
longer of such an extent as to afford a shelter for wolves and hyenas, they 
still harbour foxes, polecats, snakes, and other noxious animals, and_seve- 
ral kinds of carnivorous birds, such as the hawk. The forests in France 
and Germany still contain wolves and wild boars ; and, on most parts of 
the Continent, the forest is the place of refuge to which man flies for con- 
cealment after the commission of crime. (See Gautieri Dello Influsso dei 
Boschi, &c.) If forests in a wild state supply food to birds and insects, in a 
civilised country birds and insects may be expected to abound more or less 
wherever there are trees and shrubs to supply them with food and shelter. 
