The effect of the forest on precipitation, then, is not entirely free

from doubt, and we cannot positively affirm that the total annual

quantity of rain is diminished or increased by the destruction of the

woods, though both theoretical considerations and the balance of

testimony strongly favor the opinion that more rain falls in wooded than

in open countries. One important conclusion, at least, upon the

meteorological influence of forests is certain and undisputed: the

proposition, namely, that, within their own limits, and near their own

borders, they maintain a more uniform degree of humidity in the

atmosphere than is observed in cleared grounds. Scarcely less can it be

questioned that they promote the frequency of showers, and, if they do

not augment the amount of precipitation, they equalize its distribution

through the different seasons.

_Influence of the Forest on the Humidity of the Soil._

I have hitherto confined myself to the influence of the forest on

meteorological conditions, a subject, as has been seen, full of

difficulty and uncertainty. Its comparative effects on the temperature,

the humidity, the texture and consistence, the configuration and

distribution of the mould or arable soil, and, very often, of the

mineral strata below, and on the permanence and regularity of springs

and greater superficial watercourses, are much less disputable as well

as more easily estimated, and much more important, than its possible

value as a cause of strictly climatic equilibrium or disturbance.

The action of the forest on the earth is chiefly mechanical, but the

organic process of abstraction of water by its roots affects the

quantity of that fluid contained in the vegetable mould, and in the

mineral strata near the surface, and, consequently, the consistency of

the soil. In treating of the effects of trees on the moisture of the

atmosphere, I have said that the forest, by interposing a canopy between

the sky and the ground, and by covering the surface with a thick mantle

of fallen leaves, at once obstructed insolation and prevented the

radiation of heat from the earth. These influences go far to balance

each other; but familiar observation shows that, in summer, the forest

soil is not raised to so high a temperature as open grounds exposed to

irradiation. For this reason, and in consequence of the mechanical

resistance opposed by the bed of dead leaves to the escape of moisture,

we should expect that, except after recent rains, the superficial strata

of woodland soil would be more humid than that of cleared land. This

agrees with experience. The soil of the forest is always moist, except

in the extremest droughts, and it is exceedingly rare that a primitive

wood suffers from want of humidity. How far this accumulation of water

affects the condition of neighboring grounds by lateral infiltration, we

do not know, but we shall see, in a subsequent chapter, that water is

conveyed to great distances by this process, and we may hence infer that

the influence in question is an important one.

_Influence of the Forest on the Flow of Springs._

It is well established that the protection afforded by the forest

against the escape of moisture from its soil, insures the permanence and

regularity of natural springs, not only within the limits of the wood,

but at some distance beyond its borders, and thus contributes to the

supply of an element essential to both vegetable and animal life. As the

forests are destroyed, the springs which flowed from the woods, and,

consequently, the greater watercourses fed by them, diminish both in

number and in volume. This fact is so familiar throughout the American

States and the British Provinces, that there are few old residents of

the interior of those districts who are not able to testify to its truth

as a matter of personal observation. My own recollection suggests to me

many instances of this sort, and I remember one case where a small

mountain spring, which disappeared soon after the clearing of the ground

where it rose, was recovered about ten or twelve years ago, by simply

allowing the bushes and young trees to grow up on a rocky knoll, not

more than half an acre in extent, immediately above it, and has since

continued to flow uninterruptedly. The uplands in the Atlantic States

formerly abounded in sources and rills, but in many parts of those

States which have been cleared for above a generation or two, the hill

pastures now suffer severely from drought, and in dry seasons no longer

afford either water or herbage for cattle.

Foissac, indeed, quotes from the elder Pliny (_Nat. Hist._, xxxi, c. 30)

a passage affirming that the felling of the woods gives rise to springs

which did not exist before because the water of the soil was absorbed by

the trees; and the same meteorologist declares, as I observed in

treating of the effect of the forest on atmospheric humidity, that the

planting of trees tends to drain marshy ground, because the roots absorb

more water than falls from the air. But Pliny's statement rests on very

doubtful authority, and Foissac cites no evidence in support of his own

proposition.[193] In the American States, it is always observed that

clearing the ground not only causes running springs to disappear, but

dries up the stagnant pools and the spongy soils of the low grounds. The

first roads in those States ran along the ridges, when practicable,

because there only was the earth dry enough to allow of their

construction, and, for the same reason, the cabins of the first settlers

were perched upon the hills. As the forests have been from time to time

removed, and the face of the earth laid open to the air and sun, the

moisture has been evaporated, and the removal of the highways and of

human habitations from the bleak hills to the sheltered valleys, is one

of the most agreeable among the many improvements which later

generations have witnessed in the interior of New England and the other

Northern States.

Almost every treatise on the economy of the forest adduces numerous

facts in support of the doctrine that the clearing of the woods tends to

diminish the flow of springs and the humidity of the soil, and it might

seem unnecessary to bring forward further evidence on this point.[194]

But the subject is of too much practical importance and of too great

philosophical interest to be summarily disposed of; and it ought

particularly to be noticed that there is at least one case--that of some

loose soils which, when bared of wood, very rapidly absorb and transmit

to lower strata the water they receive from the atmosphere, as argued by

Valles[195]--where the removal of the forest may increase the flow of

springs at levels below it, by exposing to the rain and melted snow a

surface more bibulous, and at the same time less retentive, than its

original covering. Under such circumstances, the water of precipitation,

which had formerly flowed off without penetrating through the

superficial layers of leaves upon the ground--as, in very heavy showers,

it sometimes does--or been absorbed by the vegetable mould and retained

until it was evaporated, might descend through porous earth until it

meets an impermeable stratum, and then be conducted along it, until,

finally, at the outcropping of this stratum, it bursts from a hillside

as a running spring. But such instances are doubtless too rare to form a

frequent or an important exception to the general law, because it is

only under very uncommon circumstances that rain water runs off over the

surface of forest ground instead of sinking into it, and very rarely the

case that such a soil as has just been supposed is covered by a layer of

vegetable earth thick enough to retain, until it is evaporated, all the

rain that falls upon it, without imparting any water to the strata below

it.

If we look at the point under discussion as purely a question of fact,

to be determined by positive evidence and not by argument, the

observations of Boussingault are, both in the circumstances they detail,

and in the weight of authority to be attached to the testimony, among

the most important yet recorded. They are embodied in the fourth section

of the twentieth chapter of that writer's _Economie Rurale_, and I have

already referred to them on page 191 for another purpose. The interest

of the question will justify me in giving, in Boussingault's own words,

the facts and some of the remarks with which he accompanies the details

of them: "In many localities," he observes,[196] "it has been thought

that, within a certain number of years, a sensible diminution has been

perceived in the volume of water of streams utilized as a motive power;

at other points, there are grounds for believing that rivers have become

shallower, and the increasing breadth of the belt of pebbles along their

banks seems to prove the loss of a part of their water; and, finally,

abundant springs have almost dried up. These observations have been

principally made in valleys bounded by high mountains, and it is thought

to have been noticed that this diminution of the waters has immediately

followed the epoch when the inhabitants have begun to destroy,

unsparingly, the woods which were spread over the face of the land.

"These facts would indicate that, where clearings have been made,

it rains less than formerly, and this is the generally received

opinion. * * * But while the facts I have stated have been established,

it has been observed, at the same time, that, since the clearing of the

mountains, the rivers and the torrents, which seemed to have lost a part

of their water, sometimes suddenly swell, and that, occasionally, to a

degree which causes great disasters. Besides, after violent storms,

springs which had become almost exhausted have been observed to burst

out with impetuosity, and soon after to dry up again. These latter

observations, it will be easily conceived, warn us not to admit hastily

the common opinion that the felling of the woods lessens the quantity of

rain; for not only is it very possible that the quantity of rain has not

changed, but the mean volume of running water may have remained the

same, in spite of the appearance of drought presented by the rivers and

springs, at certain periods of the year. Perhaps the only difference

would be that the flow of the same quantity of water becomes more

irregular in consequence of clearing. For instance: if the low water of

the Rhone during one part of the year were exactly compensated by a

sufficient number of floods, it would follow that this river would

convey to the Mediterranean the same volume of water which it carried to

that sea in ancient times, before the period when the countries near its

source were stripped of their woods, and when, probably, its mean depth

was not subject to so great variations as in our days. If this were so,

the forests would have this value--that of regulating, of economizing in

a certain sort, the drainage of the rain water.

"If running streams really become rarer in proportion as clearing is

extended, it follows either that the rain is less abundant, or that

evaporation is greatly favored by a surface which is no longer protected

by trees against the rays of the sun and the wind. These two causes,

acting in the same direction, must often be cumulative in their effects,

and before we attempt to fix the value of each, it is proper to inquire

whether it is an established fact that running waters diminish on the

surface of a country in which extensive clearing is going on; in a word,

to examine whether an apparent fact has not been mistaken for a real

one. And here lies the practical point of the question; for if it is

once established that clearing diminishes the volume of streams, it is

less important to know to what special cause this effect is due. * * * I

shall attach no value except to facts which have taken place under the

eye of man, as it is the influence of his labors on the meteorological

condition of the atmosphere which I propose to estimate. What I am about

to detail has been observed particularly in America, but I shall

endeavor to establish, that what I believe to be true of America would

be equally so for any other continent.

"One of the most interesting parts of Venezuela is, no doubt, the valley

of Aragua. Situated at a short distance from the coast, and endowed,

from its elevation, with various climates and a soil of unexampled

fertility, its agriculture embraces at once the crops suited to tropical

regions and to Europe. Wheat succeeds well on the heights of Victoria.

Bounded on the north by the coast chain, on the south by a system of

mountains connected with the Llanos, the valley is shut in on the east

and the west by lines of hills which completely close it. In consequence

of this singular configuration, the rivers which rise within it, having

no outlet to the ocean, form, by their union, the beautiful Lake of

Tacarigua or Valencia. This lake, according to Humboldt, is larger than

that of Neufchatel; it is at an elevation of 439 metres [= 1,460 English

feet] above the sea, and its greatest length does not exceed two leagues

and a half [= seven English miles].

"At the time of Humboldt's visit to the valley of Aragua, the

inhabitants were struck by the gradual diminution which the lake had

been undergoing for thirty years. In fact, by comparing the descriptions

given by historians with its actual condition, even making large

allowance for exaggeration, it was easy to see that the level was

considerably depressed. The facts spoke for themselves. Oviedo, who,

toward the close of the sixteenth century, had often traversed the

valley of Aragua, says positively that New Valencia was founded, in

1555, at half a league from the Lake of Tacarigua; in 1800, Humboldt

found this city 5,260 metres [= 3-1/3 English miles] from the shore.

"The aspect of the soil furnished new proofs. Many hillocks on the plain

retain the name of islands, which they more justly bore when they were

surrounded by water. The ground laid bare by the retreat of the lake was

converted into admirable plantations of cotton, bananas, and sugar cane;

and buildings erected near the lake showed the sinking of the water from

year to year. In 1796, new islands made their appearance. An important

military point, a fortress built in 1740 on the island of Cabrera, was

now on a peninsula; and, finally, on two granitic islands, those of Cura

and Cabo Blanco, Humboldt observed among the shrubs, some metres above

the water, fine sand filled with helicites.

"These clear and positive facts suggested numerous explanations, all

assuming a subterranean outlet, which permitted the discharge of the

water to the ocean. Humboldt disposed of these hypotheses, and, after a

careful examination of the locality, the distinguished traveller did not

hesitate to ascribe the diminution of the waters of the lake to the

numerous clearings which had been made in the valley of Aragua within

half a century. * * *

"In 1800, the valley of Aragua possessed a population as dense as that

of any of the best-peopled parts of France. * * * Such was the

prosperous condition of this fine country when Humboldt occupied the

Hacienda de Cura.

"Twenty-two years later, I explored the valley of Aragua, fixing my

residence in the little town of Maracay. For some years previous, the

inhabitants had observed that the waters of the lake were no longer

retiring, but, on the contrary, were sensibly rising. Grounds, not long

before occupied by plantations, were submerged. The islands of Nuevas

Aparecidas, which appeared above the surface in 1796, had again become

shoals dangerous to navigation. Cabrera, a tongue of land on the north

side of the valley, was so narrow that the least rise of the water

completely inundated it. A protracted north wind sufficed to flood the

road between Maracay and New Valencia. The fears which the inhabitants

of the shores had so long entertained were reversed. * * * Those who had

explained the diminution of the lake by the supposition of subterranean

channels were suspected of blocking them up, to prove themselves in the

right.

"During the twenty-two years which had elapsed, important political

events had occurred. Venezuela no longer belonged to Spain. The peaceful

valley of Aragua had been the theatre of bloody struggles, and a war of

extermination had desolated these smiling lands and decimated their

population. At the first cry of independence a great number of slaves

found their liberty by enlisting under the banners of the new republic;

the great plantations were abandoned, and the forest, which in the

tropics so rapidly encroaches, had soon recovered a large proportion of

the soil which man had wrested from it by more than a century of

constant and painful labor.

"At the time of the growing prosperity of the valley of Aragua, the

principal affluents of the lake were diverted, to serve for irrigation,

and the rivers were dry for more than six months of the year. At the

period of my visit, their waters, no longer employed, flowed freely."

Boussingault proceeds to state that two lakes near Ubate in New Granada,

at an elevation of 2,562 metres (= 8,500 English feet), where there is a

constant temperature of 14 deg. to 16 deg. centigrade [= 57 deg., 61 deg. Fahrenheit],

had formed but one, a century before his visit; that the waters were

gradually retiring, and the plantations extending over the abandoned

bed; that, by inquiry of old hunters and by examination of parish

records, he found that extensive clearings had been made and were still

going on.

He found, also, that the length of the Lake of Fuquene, in the same

valley, had, within two centuries, been reduced from ten leagues to one

and a half, its breadth from three leagues to one. At the former period,

timber was abundant, and the neighboring mountains were covered, to a

certain height, with American oaks, laurels, and other trees of

indigenous species; but at the time of his visit the mountains had been

almost entirely stripped of their wood, chiefly to furnish fuel for

salt-works. Our author adds that other cases, similar to those already

detailed, might be cited, and he proceeds to show, by several examples,

that the waters of other lakes in the same regions, where the valleys

had always been bare of wood, or where the forests had not been

disturbed, had undergone no change of level.

Boussingault further maintains that the lakes of Switzerland have

sustained a depression of level since the too prevalent destruction of

the woods, and arrives at the general conclusion, that, "in countries

where great clearings have been made, there has most probably been a

diminution in the living waters which flow upon the surface of the

ground." This conclusion he further supports by two examples: one, where

a fine spring, at the foot of a wooded mountain in the Island of

Ascension, dried up when the mountain was cleared, but reappeared when

the wood was replanted; the other at Marmato, in the province of

Popayan, where the streams employed to drive machinery were much

diminished in volume, within two years after the clearing of the heights

from which they derived their supplies. This latter is an interesting

case, because, although the rain gauges, established as soon as the

decrease of water began to excite alarm, showed a greater fall of rain

for the second year of observation than the first, yet there was no

appreciable increase in the flow of the mill streams. From these cases,

the distinguished physicist infers that very restricted local clearings

may diminish and even suppress springs and brooks, without any reduction

in the total quantity of rain.

It will have been noticed that these observations, with the exception of

the last two cases, do not bear directly upon the question of the

diminution of springs by clearings, but they logically infer it from the

subsidence of the natural reservoirs which springs once filled. There

is, however, no want of positive evidence on this subject.

Marschand cites the following instances: "Before the felling of the

woods, within the last few years, in the valley of the Soulce, the

Combe-es-Mounin and the Little Valley, the Sorne furnished a regular

and sufficient supply of water for the iron works of Unterwyl, which was

almost unaffected by drought or by heavy rains. The Sorne has now become

a torrent, every shower occasions a flood, and after a few days of fine

weather, the current falls so low that it has been necessary to change

the water wheels, because those of the old construction are no longer

able to drive the machinery, and at last to introduce a steam engine to

prevent the stoppage of the works for want of water.

"When the factory of St. Ursanne was established, the river that

furnished its power was abundant, long known and tried, and had, from

time immemorial, sufficed for the machinery of a previous factory.

Afterward, the woods near its sources were cut. The supply of water fell

off in consequence, the factory wanted water for half the year, and was

at last obliged to stop altogether.

"The spring of Combefoulat, in the commune of Seleate, was well known as

one of the best in the country; it was remarkably abundant and

sufficient, in spite of the severest droughts, to supply all the

fountains of the town; but, as soon as considerable forests were felled

in Combe-de-pre Martin and in the valley of Combefoulat, the famous

spring which lies below these woods has become a mere thread of water,

and disappears altogether in times of drought.

"The spring of Varieux, which formerly supplied the castle of Pruntrut,

lost more than half its water after the clearing of Varieux and

Rongeoles. These woods have been replanted, the young trees are growing

well, and with the woods, the waters of the spring are increasing.

"The Dog Spring between Pruntrut and Bressancourt has entirely vanished

since the surrounding forests grounds were brought under cultivation.

"The Wolf Spring, in the commune of Soubey, furnishes a remarkable

example of the influence of the woods upon fountains. A few years ago

this spring did not exist. At the place where it now rises, a small

thread of water was observed after very long rains, but the stream

disappeared with the rain. The spot is in the middle of a very steep

pasture inclining to the south. Eighty years ago, the owner of the land,

perceiving that young firs were shooting up in the upper part of it,

determined to let them grow, and they soon formed a flourishing grove.

As soon as they were well grown, a fine spring appeared in place of the

occasional rill, and furnished abundant water in the longest droughts.

For forty or fifty years, this spring was considered the best in the

Clos du Doubs. A few years since, the grove was felled, and the ground

turned again to a pasture. The spring disappeared with the wood, and is

now as dry as it was ninety years ago."[197]

"The influence of the forest on springs," says Hummel, "is strikingly

shown by an instance at Heilbronn. The woods on the hills surrounding

the town are cut in regular succession every twentieth year. As the

annual cuttings approach a certain point, the springs yield less water,

some of them none at all; but as the young growth shoots up, they now

more and more freely, and at length bubble up again in all their

original abundance."[198]

Piper states the following case: "Within about half a mile of my

residence there is a pond upon which mills have been standing for a long

time, dating back, I believe, to the first settlement of the town. These

have been kept in constant operation until within some twenty or thirty

years, when the supply of water began to fail. The pond owes its

existence to a stream which has its source in the hills which stretch

some miles to the south. Within the time mentioned, these hills, which

were clothed with a dense forest, have been almost entirely stripped of

trees; and to the wonder and loss of the mill owners, the water in the

pond has failed, except in the season of freshets; and, what was never

heard of before, the stream itself has been entirely dry. Within the

last ten years a new growth of wood has sprung up on most of the land

formerly occupied by the old forest; and now the water runs through the

year, notwithstanding the great droughts of the last few years, going

back from 1856."

Dr. Piper quotes from a letter of William C. Bryant the following

remarks: "It is a common observation that our summers are become drier,

and our streams smaller. Take the Cuyahoga as an illustration. Fifty

years ago large barges loaded with goods went up and down that river,

and one of the vessels engaged in the battle of Lake Erie, in which the

gallant Perry was victorious, was built at Old Portage, six miles north

of Albion, and floated down to the lake. Now, in an ordinary stage of

the water, a canoe or skiff can hardly pass down the stream. Many a boat

of fifty tons burden has been built and loaded in the Tuscarawas, at New

Portage, and sailed to New Orleans without breaking bulk. Now, the river

hardly affords a supply of water at New Portage for the canal. The same

may be said of other streams--they are drying up. And from the same

cause--the destruction of our forests--our summers are growing drier,

and our winters colder."[199]

No observer has more carefully studied the influence of the forest upon

the flow of the waters, or reasoned more ably on the ascertained

phenomena than Cantegril. The facts presented in the following case,

communicated by him to the _Ami des Sciences_ for December, 1859, are as

nearly conclusive as any single instance well can be:

"In the territory of the commune of Labruguiere, there is a forest of

1,834 hectares [4,530 acres], known by the name of the Forest of

Montaut, and belonging to that commune. It extends along the northern

slope of the Black Mountains. The soil is granitic, the maximum altitude

1,243 metres [4,140 feet], and the inclination ranges between 15 and 60

to 100.

"A small current of water, the brook of Caunan, takes its rise in this

forest, and receives the waters of two thirds of its surface. At the

lower extremity of the wood and on the stream are several fulleries,

each requiring a force of eight horse-power to drive the water wheels

which work the stampers. The commune of Labruguiere had been for a long

time famous for its opposition to forest laws. Trespasses and abuses of

the right of pasturage had converted the wood into an immense waste, so

that this vast property now scarcely sufficed to pay the expense of

protecting it, and to furnish the inhabitants with a meagre supply of

fuel. While the forest was thus ruined, and the soil thus bared, the

water, after every abundant rain, made an eruption into the valley,

brought down a great quantity of pebbles which still clog the current of

the Caunan. The violence of the floods was sometimes such that they were

obliged to stop the machinery for some time. During the summer another

inconvenience was felt. If the dry weather continued a little longer

than usual, the delivery of water became insignificant. Each fullery

could for the most part only employ a single set of stampers, and it was

not unusual to see the work entirely suspended.

"After 1840, the municipal authority succeeded in enlightening the

population as to their true interests. Protected by a more watchful

supervision, aided by well-managed replantation, the forest has

continued to improve to the present day. In proportion to the

restoration of the forest, the condition of the manufactories has become

less and less precarious, and the action of the water is completely

modified. For example, there are, no longer, sudden and violent floods

which make it necessary to stop the machinery. There is no increase in

the delivery until six or eight hours after the beginning of the rain;

the floods follow a regular progression till they reach their maximum,

and decrease in the same manner. Finally, the fulleries are no longer

forced to suspend work in summer; the water is always sufficiently

abundant to allow the employment of two sets of stampers at least, and

often even of three.

"This example is remarkable in this respect, that, all other

circumstances having remained the same, the changes in the action of the

stream can be attributed only to the restoration of the forest--changes

which may be thus summed up: diminution of flood water during

rains--increase of delivery at other seasons."

_The Forest in Winter._

To estimate rightly the importance of the forest as a natural apparatus

for accumulating the water that falls upon the surface and transmitting

it to the subjacent strata, we must compare the condition and properties

of its soil with those of cleared and cultivated earth, and examine the

consequently different action of these soils at different seasons of the

year. The disparity between them is greatest in climates where, as in

the Northern American States and in the North of Europe, the open ground

freezes and remains impervious to water during a considerable part of

the winter; though, even in climates where the earth does not freeze at

all, the woods have still an important influence of the same character.

The difference is yet greater in countries which have regular wet and

dry seasons, rain being very frequent in the former period, while, in

the latter, it scarcely occurs at all. These countries lie chiefly in or

near the tropics, but they are not wanting in higher latitudes; for a

large part of Asiatic and even of European Turkey is almost wholly

deprived of summer rains. In the principal regions occupied by European

cultivation, and where alone the questions discussed in this volume are

recognized as having, at present, any practical importance, rain falls

at all seasons, and it is to these regions that, on this point as well

as others, I chiefly confine my attention.

The influence of the forest upon the waters of the earth has been more

studied in France than in any other part of the civilized world, because

that country has, in recent times, suffered most severely from the

destruction of the woods. But in the southern provinces of that empire,

where the evils resulting from this cause are most sensibly felt, the

winters are not attended with much frost, while, in Northern Europe,

where the winters are rigorous enough to freeze the ground to the depth

of some inches, or even feet, a humid atmosphere and frequent summer

rains prevent the drying up of the springs observed in southern

latitudes when the woods are gone. For these reasons, the specific

character of the forest, as a winter reservoir of moisture in countries

with a cold and dry atmosphere, has not attracted so much attention in

France and Northern Europe as it deserves in the United States, where an

excessive climate renders that function of the woods more important.

In New England, irregular as the climate is, the first autumnal snows

usually fall before the ground is frozen at all, or when the frost

extends at most to the depth of only a few inches. In the woods,

especially those situated upon the elevated ridges which supply the

natural irrigation of the soil and feed the perennial fountains and

streams, the ground remains covered with snow during the winter; for the

trees protect the snow from blowing from the general surface into the

depressions, and new accessions are received before the covering

deposited by the first fall is melted. Snow is of a color unfavorable

for radiation, but, even when it is of considerable thickness, it is not

wholly impervious to the rays of the sun, and for this reason, as well

as from the warmth of lower strata, the frozen crust, if one has been

formed, is soon thawed, and does not again fall below the freezing point

during the winter.

The snow in contact with the earth now begins to melt, with greater or

less rapidity, according to the relative temperature of the earth and

the air, while the water resulting from its dissolution is imbibed by

the vegetable mould, and carried off by infiltration so fast that both

the snow and the layers of leaves in contact with it often seem

comparatively dry, when, in fact, the under surface of the former is in

a state of perpetual thaw. No doubt a certain proportion of the snow is

returned to the atmosphere by direct evaporation, but in the woods it is

partially protected from the action of the sun, and as very little water

runs off in the winter by superficial watercourses, except in rare cases

of sudden thaw, there can be no question that much the greater part of

the snow deposited in the forest is slowly melted and absorbed by the

earth.

The quantity of snow that falls in extensive forests, far from the open

country, has seldom been ascertained by direct observation, because

there are few meteorological stations in such situations. In the

Northeastern border States of the American Union, the ground in the deep

woods is covered with snow four or five months, and the proportion of

water which falls in snow does not exceed one fifth of the total

precipitation for the year.[200] Although, in the open grounds, snow and

ice are evaporated with great rapidity in clear weather, even when the

thermometer stands far below the freezing point, the surface of the snow

in the woods does not indicate much loss in this way. Very small

deposits of snowflakes remain unevaporated in the forest, for many days

after snow let fall at the same time in the cleared field has

disappeared without either a thaw to melt it or a wind powerful enough

to drift it away. Even when bared of their leaves, the trees of a wood

obstruct, in an important degree, both the direct action of the sun's

rays on the snow, and the movement of drying and thawing winds.

Dr. Piper records the following observations: "A body of snow, one foot

in depth, and sixteen feet square, was protected from the wind by a

tight board fence about five feet high, while another body of snow, much

more sheltered from the sun than the first, six feet in depth, and about

sixteen feet square, was fully exposed to the wind. When the thaw came

on, which lasted about a fortnight, the larger body of snow was entirely

dissolved in less than a week, while the smaller body was not wholly

gone at the end of the second week.

"Equal quantities of snow were placed in vessels of the same kind and

capacity, the temperature of the air being seventy degrees. In the one

case, a constant current of air was kept passing over the open vessel,

while the other was protected by a cover. The snow in the first was

dissolved in sixteen minutes, while the latter had a small unthawed

proportion remaining at the end of eighty-five minutes."[201]

The snow in the woods is protected in the same way, though not literally

to the same extent as by the fence in one of these cases and the cover

in the other. Little of the winter precipitation, therefore, is lost by

evaporation, and as it slowly melts at bottom it is absorbed by the

earth, and but a very small quantity of water runs off from the surface.

The immense importance of the forest, as a reservoir of this stock of

moisture, becomes apparent, when we consider that a large proportion of

the summer rain either flows into the valleys and the rivers, because it

falls faster than the ground can imbibe it; or, if absorbed by the warm

superficial strata, is evaporated from them without sinking deep enough

to reach wells and springs, which, of course, depend very much on winter

rains and snows for their entire supply. This observation, though

specially true of cleared and cultivated grounds, is not wholly

inapplicable to the forest, particularly when, as is too often the case

in Europe, the underwood and the decaying leaves are removed.

The general effect of the forest in cold climates is to assimilate the

winter state of the ground to that of wooded regions under softer skies;

and it is a circumstance well worth noting, that in Southern Europe,

where nature has denied to the earth a warm winter-garment of flocculent

snow, she has, by one of those compensations in which her empire is so

rich, clothed the hillsides with umbrella pines, ilexes, cork oaks, and

other trees of persistent foliage, whose evergreen leaves afford to the

soil a protection analogous to that which it derives from snow in more

northern climates.

The water imbibed by the soil in winter sinks until it meets a more or

less impermeable, or a saturated stratum, and then, by unseen conduits,

slowly finds its way to the channels of springs, or oozes out of the

ground in drops which unite in rills, and so all is conveyed to the

larger streams, and by them finally to the sea. The water, in

percolating through the vegetable and mineral layers, acquires their

temperature, and is chemically affected by their action, but it carries

very little matter in mechanical suspension.

The process I have described is a slow one, and the supply of moisture

derived from the snow, augmented by the rains of the following seasons,

keeps the forest ground, where the surface is level or but moderately

inclined, in a state of saturation through almost the whole year. The

rivers fed by springs and shaded by woods are comparatively uniform in

volume, in temperature, and in chemical composition. Their banks are

little abraded, nor are their courses much obstructed by fallen timber,

or by earth and gravel washed down from the highlands. Their channels

are subject only to slow and gradual changes, and they carry down to the

lakes and the sea no accumulation of sand or silt to fill up their

outlets, and, by raising their beds, to force them to spread over the

low grounds near their mouth.[202]

In this state of things, destructive tendencies of all sorts are

arrested or compensated, and tree, bird, beast, and fish, alike, find a

constant uniformity of condition most favorable to the regular and

harmonious coexistence of them all.

_General Consequences of the Destruction of the Forest._

With the disappearance of the forest, all is changed. At one season, the

earth parts with its warmth by radiation to an open sky--receives, at

another, an immoderate heat from the unobstructed rays of the sun. Hence

the climate becomes excessive, and the soil is alternately parched by

the fervors of summer, and seared by the rigors of winter. Bleak winds

sweep unresisted over its surface, drift away the snow that sheltered it

from the frost, and dry up its scanty moisture. The precipitation

becomes as regular as the temperature; the melting snows and vernal

rains, no longer absorbed by a loose and bibulous vegetable mould, rush

over the frozen surface, and pour down the valleys seaward, instead of

filling a retentive bed of absorbent earth, and storing up a supply of

moisture to feed perennial springs. The soil is bared of its covering of

leaves, broken and loosened by the plough, deprived of the fibrous

rootlets which held it together, dried and pulverized by sun and wind,

and at last exhausted by new combinations. The face of the earth is no

longer a sponge, but a dust heap, and the floods which the waters of the

sky pour over it hurry swiftly along its slopes, carrying in suspension

vast quantities of earthy particles which increase the abrading power

and mechanical force of the current, and, augmented by the sand and

gravel of falling banks, fill the beds of the streams, divert them into

new channels and obstruct their outlets. The rivulets, wanting their

former regularity of supply and deprived of the protecting shade of the

woods, are heated, evaporated, and thus reduced in their summer

currents, but swollen to raging torrents in autumn and in spring. From

these causes, there is a constant degradation of the uplands, and a

consequent elevation of the beds of watercourses and of lakes by the

deposition of the mineral and vegetable matter carried down by the

waters. The channels of great rivers become unnavigable, their estuaries

are choked up, and harbors which once sheltered large navies are shoaled

by dangerous sandbars. The earth, stripped of its vegetable glebe, grows

less and less productive, and, consequently, less able to protect itself

by weaving a new network of roots to bind its particles together, a new

carpeting of turf to shield it from wind and sun and scouring rain.

Gradually it becomes altogether barren. The washing of the soil from the

mountains leaves bare ridges of sterile rock, and the rich organic mould

which covered them, now swept down into the dank low grounds, promotes a

luxuriance of aquatic vegetation that breeds fever, and more insidious

forms of mortal disease, by its decay, and thus the earth is rendered no

longer fit for the habitation of man.[203]

To the general truth of this sad picture there are many exceptions, even

in countries of excessive climates. Some of these are due to favorable

conditions of surface, of geological structure, and of the distribution

of rain; in many others, the evil consequences of man's improvidence

have not yet been experienced, only because a sufficient time has not

elapsed, since the felling of the forest, to allow them to develop

themselves. But the vengeance of nature for the violation of her

harmonies, though slow, is sure, and the gradual deterioration of soil

and climate in such exceptional regions is as certain to result from the

destruction of the woods as is any natural effect to follow its cause.

In the vast farrago of crudities which the elder Pliny's ambition of

encyclopaedic attainment and his ready credulity have gathered together,

we meet some judicious observations. Among these we must reckon the

remark with which he accompanies his extraordinary statement respecting

the prevention of springs by the growth of forest trees, though, as is

usual with him, his philosophy is wrong. "Destructive torrents are

generally formed when hills are stripped of the trees which formerly

confined and absorbed the rains." The absorption here referred to is not

that of the soil, but of the roots, which, Pliny supposed, drank up the

water to feed the growth of the trees.

Although this particular evil effect of too extensive clearing was so

early noticed, the lesson seems to have been soon forgotten. The

legislation of the Middle Ages in Europe is full of absurd provisions

concerning the forests, which sovereigns sometimes destroyed because

they furnished a retreat for rebels and robbers, sometimes protected

because they were necessary to breed stags and boars for the chase, and

sometimes spared with the more enlightened view of securing a supply of

timber and of fuel to future generations.[204] It was reserved to later

ages to appreciate their geographical importance, and it is only in very

recent times, only in a few European countries, that the too general

felling of the woods has been recognized as the most destructive among

the many causes of the physical deterioration of the earth.

_Condition of the Forest, and its Literature in different Countries._

The literature of the forest, which in England and America has not yet

become sufficiently extensive to be known as a special branch of

authorship, counts its thousands of volumes in Germany, Italy, and

France. It is in the latter country, perhaps, that the relations of the

woods to the regular drainage of the soil, and especially to the

permanence of the natural configuration of terrestrial surface, have

been most thoroughly investigated. On the other hand, the purely

economical aspects of sylviculture have been most satisfactorily

expounded, and that art has been most philosophically discussed, and

most skilfully and successfully practised, in Germany.

The eminence of Italian theoretical hydrographers and the great ability

of Italian hydraulic engineers are well known, but the specific

geographical importance of the woods has not been so clearly recognized

in Italy as in the states bordering it on the north and west. It is true

that the face of nature has been as completely revolutionized by man,

and that the action of torrents has created as wide and as hopeless

devastation in that country as in France; but in the French Empire the

desolation produced by clearing the forests is more recent,[205] has

been more suddenly effected, and, therefore, excites a livelier and more

general interest than in Italy, where public opinion does not so readily

connect the effect with its true cause. Italy, too, from ancient habit,

employs little wood in architectural construction; for generations she

has maintained no military or commercial marine large enough to require

exhaustive quantities of timber,[206] and the mildness of her climate

makes small demands on the woods for fuel. Besides these circumstances,

it must be remembered that the sciences of observation did not become

knowledges of practical application till after the mischief was already

mainly done and even forgotten in Alpine Italy, while its evils were

just beginning to be sensibly felt in France when the claims of natural

philosophy as a liberal study were first acknowledged in modern Europe.

The former political condition of the Italian Peninsula would have

effectually prevented the adoption of a general system of forest

economy, however clearly the importance of a wise administration of this

great public interest might have been understood. The woods which

controlled and regulated the flow of the river sources were very often

in one jurisdiction, the plains to be irrigated, or to be inundated by

floods and desolated by torrents, in another. Concert of action on such

a subject between a multitude of jealous petty sovereignties was

obviously impossible, and nothing but the union of all the Italian

states under a single government can render practicable the

establishment of such arrangements for the conservation and restoration

of the forests and the regulation of the flow of the waters as are

necessary for the full development of the yet unexhausted resources of

that fairest of lands, and even for the permanent maintenance of the

present condition of its physical geography.

The denudation of the Central and Southern Apennines and of the Italian

declivity of the Western Alps began at a period of unknown antiquity,

but it does not seem to have been carried to a very dangerous length

until the foreign conquests and extended commerce of Rome created a

greatly increased demand for wood for the construction of ships and for

military material. The Eastern Alps, the Western Apennines, and the

Maritime Alps retained their forests much later; but even here the want

of wood, and the injury to the plains and the navigation of the rivers

by sediment brought down by the torrents, led to some legislation for

the protection of the forests, by the Republic of Venice in the

fifteenth century, by that of Genoa as early at least as the

seventeenth; and Marschand states that the latter Government passed laws

requiring the proprietors of mountain lands to replant the woods. These,

however, do not seem to have been effectually enforced. It is very

common in Italy to ascribe to the French occupation under the first

Empire all the improvements, and all the abuses of recent times,

according to the political sympathies of the individual; and the French

are often said to have prostrated every forest which has disappeared

within a century.[207] But, however this may be, no energetic system of

repression or restoration was adopted by any of the Italian states after

the downfall of the Empire, and the taxes on forest property in some of

them were so burdensome that rural municipalities sometimes proposed to

cede their common woods to the Government, without any other

compensation than the remission of the taxes imposed on forest

lands.[208] Under such circumstances, woodlands would soon become

disafforested, and where facilities of transportation and a good demand

for timber have increased the inducements to fell it, as upon the

borders of the Mediterranean, the destruction of the forest and all the

evils which attend it have gone on at a seriously alarming rate. It has

even been calculated that four tenths of the area of the Ligurian

provinces have been washed away or rendered incapable of cultivation by

the felling of the woods.[209]

The damp and cold climate of England requires the maintenance of

household fires through a large part of the year. Contrivances for

economizing fuel were of later introduction in that country than on the

Continent. The soil, like the sky, was, in general, charged with

humidity; its natural condition was unfavorable for common roads, and

the transportation of so heavy a material as coal, by land, from the

remote counties where alone it was mined in the Middle Ages, was costly

and difficult. For all these reasons, the consumption of wood was large,

and apprehensions of the exhaustion of the forests were excited at an

early period. Legislation there, as elsewhere, proved ineffectual to

protect them, and many authors of the sixteenth century express fears of

serious evils from the wasteful economy of the people in this respect.

Harrison, in his curious chapter "Of Woods and Marishes" in Holinshed's

compilation, complains of the rapid decrease of the forests, and adds:

"Howbeit thus much I dare affirme, that if woods go so fast to decaie in

the next hundred yeere of Grace, as they haue doone and are like to doo

in this, * * * it is to be feared that the fennie bote, broome, turfe,

gall, heath, firze, brakes, whinnes, ling, dies, hassacks, flags, straw,

sedge, reed, rush, and also _seacole_, will be good merchandize euen

in the citie of London, whereunto some of them euen now haue gotten

readie passage, and taken vp their innes in the greatest merchants'

parlours. * * * I would wish that I might liue no longer than to see

foure things in this land reformed, that is: the want of discipline in

the church: the couetous dealing of most of our merchants in the

preferment of the commodities of other countries, and hinderance of

their owne: the holding of faires and markets vpon the sundaie to be

abolished and referred to the wednesdaies: and that euerie man, in

whatsoeuer part of the champaine soile enioieth fortie acres of land,

and vpwards, after that rate, either by free deed, copie hold, or fee

farme, might plant one acre of wood, or sowe the same with oke mast,

hasell, beech, and sufficient prouision be made that it may be cherished

and kept. But I feare me that I should then liue too long, and so long,

that I should either be wearie of the world, or the world of me."[210]

Evelyn's "Silva," the first edition of which appeared in 1664, rendered

an extremely important service to the cause of the woods, and there is

no doubt that the ornamental plantations in which England far surpasses

all other countries, are, in some measure, the fruit of Evelyn's

enthusiasm. In England, however, arboriculture, the planting and nursing

of single trees, has, until recently, been better understood than

sylviculture, the sowing and training of the forest. But this latter

branch of rural improvement is now pursued on a very considerable scale,

though, so far as I know, not by the National Government.

_The Influence of the Forest on Inundations._

Besides the climatic question, which I have already sufficiently

discussed, and the obvious inconveniences of a scanty supply of

charcoal, of fuel, and of timber for architectural and naval

construction and for the thousand other uses to which wood is applied in

rural and domestic economy, and in the various industrial processes of

civilized life, the attention of French foresters and public economists

has been specially drawn to three points, namely: the influence of the

forests on the permanence and regular flow of springs or natural

fountains; on inundations by the overflow of rivers; and on the abrasion

of soil and the transportation of earth, gravel, pebbles, and even of

considerable masses of rock, from higher to lower levels, by torrents.

There are, however, connected with this general subject, several other

topics of minor or strictly local interest, or of more uncertain

character, which I shall have occasion more fully to speak of hereafter.

The first of these three principal subjects--the influence of the woods

on springs and other living waters--has been already considered; and if

the facts stated in that discussion are well established, and the

conclusions I have drawn from them are logically sound, it would seem to

follow, as a necessary corollary, that the action of the forest is as

important in diminishing the frequency and violence of river floods, as

in securing the permanence and equability of natural fountains; for any

cause which promotes the absorption and accumulation of the water of

precipitation by the superficial strata of the soil, to be slowly given

out by infiltration and percolation, must, by preventing the rapid flow

of surface water into the natural channels of drainage, tend to check

the sudden rise of rivers, and, consequently, the overflow of their

banks, which constitutes what is called inundation. The mechanical

resistance, too, offered by the trunks of trees and of undergrowth to

the flow of water over the surface, tends sensibly to retard the

rapidity of its descent down declivities, and to divert and divide

streams which may have already accumulated from smaller threads of

water.[211]

Inundations are produced by the insufficiency of the natural channels of

rivers to carry off the waters of their basins as fast as those waters

flow into them. In accordance with the usual economy of nature, we

should presume that she had everywhere provided the means of

discharging, without disturbance of her general arrangements or abnormal

destruction of her products, the precipitation which she sheds upon the

face of the earth. Observation confirms this presumption, at least in

the countries to which I confine my inquiries; for, so far as we know

the primitive conditions of the regions brought under human occupation

within the historical period, it appears that the overflow of river

banks was much less frequent and destructive than at the present day,

or, at least, that rivers rose and fell less suddenly before man had

removed the natural checks to the too rapid drainage of the basins in

which their tributaries originate. The banks of the rivers and smaller

streams in the North American colonies were formerly little abraded by

the currents. Even now the trees come down almost to the water's edge

along the rivers, in the larger forests of the United States, and the

surface of the streams seems liable to no great change in level or in

rapidity of current. A circumstance almost conclusive as to the

regularity of flow in forest rivers, is that they do not form large

sedimentary deposits, at their points of discharge into lakes or larger

streams, such accumulations beginning, or at least advancing far more

rapidly, after the valleys are cleared.

In the Northern United States, although inundations are sometimes

produced in the height of summer by heavy rains, it will be found

generally true that the most rapid rise of the waters, and, of course,

the most destructive "freshets," as they are called in America, are

produced by the sudden dissolution of the snow before the open ground is

thawed in the spring. It frequently happens that a powerful thaw sets in

after a long period of frost, and the snow which had been months in

accumulating is dissolved and carried off in a few hours. When the snow

is deep, it, to use a popular expression, "takes the frost out of the

ground" in the woods, and, if it lies long enough, in the fields also.

But the heaviest snows usually fall after midwinter, and are succeeded

by warm rains or sunshine, which dissolve the snow on the cleared land

before it has had time to act upon the frost-bound soil beneath it. In

this case, the snow in the woods is absorbed as fast as it melts, by the

soil it has protected from freezing, and does not materially contribute

to swell the current of the rivers. If the mild weather, in which great

snowstorms usually occur, does not continue and become a regular thaw,

it is almost sure to be followed by drifting winds, and the inequality

with which they distribute the snow leaves the ridges comparatively

bare, while the depressions are often filled with drifts to the height

of many feet. The knolls become frozen to a great depth; succeeding

partial thaws melt the surface snow, and the water runs down into the

furrows of ploughed fields, and other artificial and natural hollows,

and then often freezes to solid ice. In this state of things, almost the

entire surface of the cleared land is impervious to water, and from the

absence of trees and the general smoothness of the ground, it offers

little mechanical resistance to superficial currents. If, under these

circumstances, warm weather accompanied by rain occurs, the rain and

melted snow are swiftly hurried to the bottom of the valleys and

gathered to raging torrents.

It ought further to be considered that, though the lighter ploughed

soils readily imbibe a great deal of water, yet the grass lands, and all

the heavy and tenacious earths, absorb it in much smaller quantities,

and less rapidly than the vegetable mould of the forest. Pasture,

meadow, and clayey soils, taken together, greatly predominate over the

sandy ploughed fields, in all large agricultural districts, and hence,

even if, in the case we are supposing, the open ground chance to have

been thawed before the melting of the snow which covers it, it is

already saturated with moisture, or very soon becomes so, and, of

course, cannot relieve the pressure by absorbing more water. The

consequence is that the face of the country is suddenly flooded with a

quantity of melted snow and rain equivalent to a fall of six or eight

inches of the latter, or even more. This runs unobstructed to rivers

often still bound with thick ice, and thus inundations of a fearfully

devastating character are produced. The ice bursts, from the hydrostatic

pressure from below, or is violently torn up by the current, and is

swept by the impetuous stream, in large masses and with resistless fury,

against banks, bridges, dams, and mills erected near them. The bark of

the trees along the rivers is often abraded, at a height of many feet

above the ordinary water level, by cakes of floating ice, which are at

last stranded by the receding flood on meadow or ploughland, to delay,

by their chilling influence, the advent of the tardy spring.

The surface of a forest, in its natural condition, can never pour forth

such deluges of water as flow from cultivated soil. Humus, or vegetable

mould, is capable of absorbing almost twice its own weight of water. The

soil in a forest of deciduous foliage is composed of humus, more or less

unmixed, to the depth of several inches, sometimes even of feet, and

this stratum is usually able to imbibe all the water possibly resulting

from the snow which at any one time covers it. But the vegetable mould

does not cease to absorb water when it becomes saturated, for it then

gives off a portion of its moisture to the mineral earth below, and thus

is ready to receive a new supply; and, besides, the bed of leaves not

yet converted to mould takes up and retains a very considerable

proportion of snow water, as well as of rain.

In the warm climates of Southern Europe, as I have already said, the

functions of the forest, so far as the disposal of the water of

precipitation is concerned, are essentially the same at all seasons, and

are analogous to those which it performs in the Northern United States

in summer. Hence, in the former countries, the winter floods have not

the characteristics which mark them in the latter, nor is the

conservative influence of the woods in winter relatively so important,

though it is equally unquestionable.

If the summer floods in the United States are attended with less

pecuniary damage than those of the Loire and other rivers of France, the

Po and its tributaries in Italy, the Emme and her sister torrents which

devastate the valleys of Switzerland, it is partly because the banks of

American rivers are not yet lined with towns, their shores and the

bottoms which skirt them not yet covered with improvements whose cost is

counted by millions, and, consequently, a smaller amount of property is

exposed to injury by inundation. But the comparative exemption of the

American people from the terrible calamities which the overflow of

rivers has brought on some of the fairest portions of the Old World, is,

in a still greater degree, to be ascribed to the fact that, with all our

thoughtless improvidence, we have not yet bared all the sources of our

streams, not yet overthrown all the barriers which nature has erected to

restrain her own destructive energies. Let us be wise in time, and

profit by the errors of our older brethren!

The influence of the forest in preventing inundations has been very

generally recognized, both as a theoretical inference and as a fact of

observation; but Belgrand and his commentator Valles have deduced an

opposite result from various facts of experience and from scientific

considerations. They contend that the superficial drainage is more

regular from cleared than from wooded ground, and that clearing

diminishes rather than augments the intensity of inundations. Neither of

these conclusions is warranted by their data or their reasoning, and

they rest partly upon facts, which, truly interpreted, are not

inconsistent with the received opinions on these subjects, partly upon

assumptions which are contradicted by experience. Two of these latter

are, first, that the fallen leaves in the forest constitute an

impermeable covering of the soil over, not through, which the water of

rains and of melting snows flows off, and secondly, that the roots of

trees penetrate and choke up the fissures in the rocks, so as to impede

the passage of water through channels which nature has provided for its

descent to lower strata.

As to the first of these, we may appeal to familiar facts within the

personal knowledge of every man acquainted with the operations of sylvan

nature. I have before me a letter from an acute and experienced

observer, containing this paragraph: "I think that rain water does not

ever, except in very trifling quantities, flow over the leaves in the

woods in summer or autumn. Water runs over them only in the spring, when

they are pressed down smoothly and compactly, a state in which they

remain only until they are dry, when shrinkage and the action of the

wind soon roughen the surface so as effectually to stop, by absorption,

all flow of water." I have observed that when a sudden frost succeeds a

thaw at the close of the winter after the snow has principally

disappeared, the water in and between the layers of leaves sometimes

freezes into a solid crust, which allows the flow of water over it. But

this occurs only in depressions and on a very small scale; and the ice

thus formed is so soon dissolved that no sensible effect is produced on

the escape of water from the general surface.

As to the influence of roots upon drainage, I believe there is no doubt

that they, independently of their action as absorbents, mechanically

promote it. Not only does the water of the soil follow them

downward,[212] but their swelling growth powerfully tends to enlarge the

crevices of rock into which they enter; and as the fissures in rocks are

longitudinal, not mere circular orifices, every line of additional width

gained by the growth of roots within them increases the area of the

crevice in proportion to its length. Consequently, the widening of a

fissure to the extent of one inch might give an additional drainage

equal to a square foot of open tubing.

The observations and reasonings of Belgrand and Valles, though their

conclusions have not been accepted by many, are very important in one

point of view. These writers insist much on the necessity of taking into

account, in estimating the relations between precipitation and

evaporation, the abstraction of water from the surface and surface

currents, by absorption and infiltration--an element unquestionably of

great value, but hitherto much neglected by meteorological inquirers,

who have very often reasoned as if the surface earth were either

impermeable to water, or already saturated with it; whereas, in fact, it

is a sponge, always imbibing humidity and always giving it off, not by

evaporation only, but by infiltration and percolation.

The destructive effects of inundations considered simply as a mechanical

power by which life is endangered, crops destroyed, and the artificial

constructions of man overthrown, are very terrible. Thus far, however,

the flood is a temporary and by no means an irreparable evil, for if its

ravages end here, the prolific powers of nature and the industry of man

soon restore what had been lost, and the face of the earth no longer

shows traces of the deluge that had overwhelmed it. Inundations have

even their compensations. The structures they destroy are replaced by

better and more secure erections, and if they sweep off a crop of corn,

they not unfrequently leave behind them, as they subside, a fertilizing

deposit which enriches the exhausted field for a succession of

seasons.[213] If, then, the too rapid flow of the surface waters

occasioned no other evil than to produce, once in ten years upon the

average, an inundation which should destroy the harvest of the low

grounds along the rivers, the damage would be too inconsiderable, and of

too transitory a character, to warrant the inconveniences and the

expense involved in the measures which the most competent judges in many

parts of Europe believe the respective governments ought to take to

obviate it.

_Destructive Action of Torrents._

But the great, the irreparable, the appalling mischiefs which have

already resulted, and threaten to ensue on a still more extensive scale

hereafter, from too rapid superficial drainage, are of a properly

geographical character, and consist primarily in erosion, displacement,

and transportation of the superficial strata, vegetable and mineral--of

the integuments, so to speak, with which nature has clothed the skeleton

framework of the globe. It is difficult to convey by description an idea

of the desolation of the regions most exposed to the ravages of torrent

and of flood; and the thousands, who, in these days of travel, are

whirled by steam near or even through the theatres of these calamities,

have but rare and imperfect opportunities of observing the destructive

causes in action. Still more rarely can they compare the past with the

actual condition of the provinces in question, and trace the progress of

their conversion from forest-crowned hills, luxuriant pasture grounds,

and abundant cornfields and vineyards well watered by springs and

fertilizing rivulets, to bald mountain ridges, rocky declivities, and

steep earth banks furrowed by deep ravines with beds now dry, now filled

by torrents of fluid mud and gravel hurrying down to spread themselves

over the plain, and dooming to everlasting barrenness the once

productive fields. In traversing such scenes, it is difficult to resist

the impression that nature pronounced the curse of perpetual sterility

and desolation upon these sublime but fearful wastes, difficult to

believe that they were once, and but for the folly of man might still

be, blessed with all the natural advantages which Providence has

bestowed upon the most favored climes. But the historical evidence is

conclusive as to the destructive changes occasioned by the agency of man

upon the flanks of the Alps, the Apennines, the Pyrenees, and other

mountain ranges in Central and Southern Europe, and the progress of

physical deterioration has been so rapid that, in some localities, a

single generation has witnessed the beginning and the end of the

melancholy revolution.

It is certain that a desolation, like that which has overwhelmed many

once beautiful and fertile regions of Europe, awaits an important part

of the territory of the United States, and of other comparatively new

countries over which European civilization is now extending its sway,

unless prompt measures are taken to check the action of destructive

causes already in operation. It is vain to expect that legislation can

do anything effectual to arrest the progress of the evil in those

countries, except so far as the state is still the proprietor of

extensive forests. Woodlands which have passed into private hands will

everywhere be managed, in spite of legal restrictions, upon the same

economical principles as other possessions, and every proprietor will,

as a general rule, fell his woods, unless he believes that it will be

for his pecuniary interest to preserve them. Few of the new provinces

which the last three centuries have brought under the control of the

European race, would tolerate any interference by the law-making power

with what they regard as the most sacred of civil rights--the right,

namely, of every man to do what he will with his own. In the Old World,

even in France, whose people, of all European nations, love best to be

governed and are least annoyed by bureaucratic supervision, law has been

found impotent to prevent the destruction, or wasteful economy, of

private forests; and in many of the mountainous departments of that

country, man is at this moment so fast laying waste the face of the

earth, that the most serious fears are entertained, not only of the

depopulation of those districts, but of enormous mischiefs to the

provinces contiguous to them.[214] The only legal provisions from which

anything is to be hoped, are such as shall make it a matter of private

advantage to the landholder to spare the trees upon his grounds, and

promote the growth of the young wood. Something may be done by exempting

standing forests from taxation, and by imposing taxes on wood felled for

fuel or for timber, something by premiums or honorary distinctions for

judicious management of the woods. It would be difficult to induce

governments, general or local, to make the necessary appropriations for

such purposes, but there can be no doubt that it would be sound economy

in the end.

In countries where there exist municipalities endowed with an

intelligent public spirit, the purchase and control of forests by such

corporations would often prove advantageous; and in some of the

provinces of Northern Lombardy, experience has shown that such

operations may be conducted with great benefit to all the interests

connected with the proper management of the woods. In Switzerland, on

the other hand, except in some few cases where woods have been preserved

as a defence against avalanches, the forests of the communes have been

productive of little advantage to the public interests, and have very

generally gone to decay. The rights of pasturage, everywhere destructive

to trees, combined with toleration of trespasses, have so reduced their

value, that there is, too often, nothing left that is worth protecting.

In the canton of Ticino, the peasants have very frequently voted to sell

the town woods and divide the proceeds among the corporators. The

sometimes considerable sums thus received are squandered in wild

revelry, and the sacrifice of the forests brings not even a momentary

benefit to the proprietors.[215]

It is evidently a matter of the utmost importance that the public, and

especially land owners, be roused to a sense of the dangers to which the

indiscriminate clearing of the woods may expose not only future

generations, but the very soil itself. Fortunately, some of the American

States, as well as the governments of many European colonies, still

retain the ownership of great tracts of primitive woodland. The State of

New York, for example, has, in its northeastern counties, a vast extent

of territory in which the lumberman has only here and there established

his camp, and where the forest, though interspersed with permanent

settlements, robbed of some of its finest pine groves, and often ravaged

by devastating fires, still covers far the largest proportion of the

surface. Through this territory, the soil is generally poor, and even

the new clearings have little of the luxuriance of harvest which

distinguishes them elsewhere. The value of the land for agricultural

uses is therefore very small, and few purchases are made for any other

purpose than to strip the soil of its timber. It has been often proposed

that the State should declare the remaining forest the inalienable

property of the commonwealth, but I believe the motive of the suggestion

has originated rather in poetical than in economical views of the

subject. Both these classes of considerations have a real worth. It is

desirable that some large and easily accessible region of American soil

should remain, as far as possible, in its primitive condition, at once a

museum for the instruction of the student, a garden for the recreation

of the lover of nature, and an asylum where indigenous tree, and humble

plant that loves the shade, and fish and fowl and four-footed beast, may

dwell and perpetuate their kind, in the enjoyment of such imperfect

protection as the laws of a people jealous of restraint can afford them.

The immediate loss to the public treasury from the adoption of this

policy would be inconsiderable, for these lands are sold at low rates.

The forest alone, economically managed, would, without injury, and even

with benefit to its permanence and growth, soon yield a regular income

larger than the present value of the fee.

The collateral advantages of the preservation of these forests would be

far greater. Nature threw up those mountains and clothed them with lofty

woods, that they might serve as a reservoir to supply with perennial

waters the thousand rivers and rills that are fed by the rains and snows

of the Adirondacks, and as a screen for the fertile plains of the

central counties against the chilling blasts of the north wind, which

meet no other barrier in their sweep from the Arctic pole. The climate

of Northern New York even now presents greater extremes of temperature

than that of Southern France. The long continued cold of winter is far

more intense, the short heats of summer not less fierce than in

Provence, and hence the preservation of every influence that tends to

maintain an equilibrium of temperature and humidity is of cardinal

importance. The felling of the Adirondack woods would ultimately involve

for Northern and Central New York consequences similar to those which

have resulted from the laying bare of the southern and western

declivities of the French Alps and the spurs, ridges, and detached peaks

in front of them.

It is true that the evils to be apprehended from the clearing of the

mountains of New York may be less in degree than those which a similar

cause has produced in Southern France, where the intensity of its action

has been increased by the inclination of the mountain declivities, and

by the peculiar geological constitution of the earth. The degradation of

the soil is, perhaps, not equally promoted by a combination of the same

circumstances, in any of the American Atlantic States, but still they

have rapid slopes and loose and friable soils enough to render

widespread desolation certain, if the further destruction of the woods

is not soon arrested. The effects of clearing are already perceptible in

the comparatively unviolated region of which I am speaking. The rivers

which rise in it flow with diminished currents in dry seasons, and with

augmented volumes of water after heavy rains. They bring down much

larger quantities of sediment, and the increasing obstructions to the

navigation of the Hudson, which are extending themselves down the

channel in proportion as the fields are encroaching upon the forest,

give good grounds for the fear of serious injury to the commerce of the

important towns on the upper waters of that river, unless measures are

taken to prevent the expansion of "improvements" which have already been

carried beyond the demands of a wise economy.

I have stated, in a general way, the nature of the evils in question,

and of the processes by which they are produced; but I shall make their

precise character and magnitude better understood by presenting some

descriptive and statistical details of facts of actual occurrence. I

select for this purpose the southeastern portion of France, not because

that territory has suffered more severely than some others, but because

its deterioration is comparatively recent, and has been watched and

described by very competent and trustworthy observers, whose reports are

more easily accessible than those published in other countries.[216]

The provinces of Dauphiny, Avignon, and Provence comprise a territory of

fourteen or fifteen thousand square miles, bounded northwest by the

Isere, northeast and east by the Alps, south by the Mediterranean, west

by the Rhone, and extending from 42 deg. to about 45 deg. of north latitude. The

surface is generally hilly and even mountainous, and several of the

peaks in Dauphiny rise above the limit of perpetual snow. The climate,

as compared with that of the United States in the same latitude, is

extremely mild. Little snow falls, except upon the higher mountain

ranges, the frosts are light, and the summers long, as might, indeed, be

inferred from the vegetation; for in the cultivated districts, the vine

and the fig everywhere flourish, the olive thrives as far north as

431/2 deg., and upon the coast, grow the orange, the lemon, and the date

palm. The forest trees, too, are of southern type, umbrella pines,

various species of evergreen oaks, and many other trees and shrubs of

persistent broad-leaved foliage, characterizing the landscape.

The rapid slope of the mountains naturally exposed these provinces to

damage by torrents, and the Romans diminished their injurious effects by

erecting, in the beds of ravines, barriers of rocks loosely piled up,

which permitted a slow escape of the water, but compelled it to deposit

above the dikes the earth and gravel with which it was charged.[217] At

a later period the Crusaders brought home from Palestine, with much

other knowledge gathered from the wiser Moslems, the art of securing the

hillsides and making them productive by terracing and irrigation. The

forests which covered the mountains secured an abundant flow of springs,

and the process of clearing the soil went on so slowly that, for

centuries, neither the want of timber and fuel, nor the other evils

about to be depicted, were seriously felt. Indeed, throughout the Middle

Ages, these provinces were well wooded, and famous for the fertility and

abundance, not only of the low grounds, but of the hills.

Such was the state of things at the close of the fifteenth century. The

statistics of the seventeenth show that while there had been an increase

of prosperity and population in Lower Provence, as well as in the

correspondingly situated parts of the other two provinces I have

mentioned, there was an alarming decrease both in the wealth and in the

population of Upper Provence and Dauphiny, although, by the clearing of

the forests, a great extent of plough land and pasturage had been added

to the soil before reduced to cultivation. It was found, in fact, that

the augmented violence of the torrents had swept away, or buried in sand

and gravel, more land than had been reclaimed by clearing; and the taxes

computed by fires or habitations underwent several successive reductions

in consequence of the gradual abandonment of the wasted soil by its

starving occupants. The growth of the large towns on and near the Rhone

and the coast, their advance in commerce and industry, and the

consequently enlarged demand for agricultural products, ought naturally

to have increased the rural population and the value of their lands; but

the physical decay of the uplands was such that considerable tracts were

deserted altogether, and in Upper Provence, the fires which in 1471

counted 897, were reduced to 747 in 1699, to 728 in 1733, and to 635 in

1776.

These facts I take from the _La Provence au point de vue des Bois, des

Torrents et des Inondations_, of Charles de Ribbe, one of the highest

authorities, and I add further details from the same source.

"Commune of Barles, 1707: Two hills have become connected by land

slides, and have formed a lake which covers the best part of the soil.

1746: New slides buried twenty houses composing a village, no trace of

which is left; more than one third of the land had disappeared.

"Monans, 1724: Deserted by its inhabitants and no longer cultivated.

"Gueydan, 1760: It appears by records that the best grounds have been

swept off since 1756, and that ravines occupy their place.

"Digne, 1762: The river Bleone has destroyed the most valuable part of

the territory.

"Malmaison, 1768: The inhabitants have emigrated, all their fields

having been lost."

In the case of the commune of St. Laurent du Var, it appears that, after

clearings in the Alps, succeeded by others in the common woods of the

town, the floods of the torrent Var became more formidable, and had

already carried off much land as early as 1708. "The clearing continued,

and more soil was swept away in 1761. In 1762, after another destructive

inundation, many of the inhabitants emigrated, and in 1765, one half of

the territory had been laid waste.

"In 1766, the assessor Serraire said to the Assembly: 'As to the damage

caused by brooks and torrents, it is impossible to deny its extent.

Upper Provence is in danger of total destruction, and the waters which

lay it waste threaten also the ruin of the most valuable grounds on the

plain below. Villages have been almost submerged by torrents which

formerly had not even names, and large towns are on the point of

destruction from the same cause.'"

In 1776, Viscount Puget thus reported: "The mere aspect of Upper

Provence is calculated to appal the patriotic magistrate. One sees only

lofty mountains, deep valleys with precipitous sides, rivers with broad

beds and little water, impetuous torrents, which in floods lay waste the

cultivated land upon their banks and roll huge rocks along their

channels; steep and parched hillsides, the melancholy consequences of

indiscriminate clearing; villages whose inhabitants, finding no longer

the means of subsistence, are emigrating day by day; houses dilapidated

to huts, and but a miserable remnant of population."

"In a document of the year 1771, the ravages of the torrents were

compared to the effects of an earthquake, half the soil in many communes

seeming to have been swallowed up.

"Our mountains," said the administrators of the province of the Lower

Alps in 1792, "present nothing but a surface of stony tufa; clearing is

still going on, and the little rivulets are becoming torrents. Many

communes have lost their harvests, their flocks, and their houses by

floods. The washing down of the mountains is to be ascribed to the

clearings and the practice of burning them over."

These complaints, it will be seen, all date before the Revolution, but

the desolation they describe has since advanced with still swifter

steps.

Surell--whose valuable work, _Etude sur les Torrents des Hautes Alpes_,

published in 1841, presents the most appalling picture of the

desolations of the torrent, and, at the same time, the most careful

studies of the history and essential character of this great evil--in

speaking of the valley of Devoluy, on page 152, says: "Everything

concurs to show that it was anciently wooded. In its peat bogs are

found buried trunks of trees, monuments of its former vegetation. In the

framework of old houses, one sees enormous timber, which is no longer to

be found in the district. Many localities, now completely bare, still

retain the name of 'wood,' and one of them is called, in old deeds,

_Comba nigra_ [Black forest or dell], on account of its dense woods.

These and many other proofs confirm the local traditions which are

unanimous on this point.

"There, as everywhere in the Upper Alps, the clearings began on the

flanks of the mountains, and were gradually extended into the valleys

and then to the highest accessible peaks. Then followed the Revolution,

and caused the destruction of the remainder of the trees which had thus

far escaped the woodman's axe."

In a note to this passage, the writer says: "Several persons have told

me that they had lost flocks of sheep, by straying, in the forests of

Mont Auroux, which covered the flanks of the mountain from La Cluse to

Agneres. These declivities are now as bare as the palm of the hand."

The ground upon the steep mountains being once bared of trees, and the

underwood killed by the grazing of horned cattle, sheep, and goats,

every depression becomes a watercourse. "Every storm," says Surell, page

153, "gives rise to a new torrent. Examples of such are shown, which,

though not yet three years old, have laid waste the finest fields of

their valleys, and whole villages have narrowly escaped being swept into

ravines formed in the course of a few hours. Sometimes the flood pours

in a sheet over the surface, without ravine or even bed, and ruins

extensive grounds, which are abandoned forever."

I cannot follow Surell in his description and classification of

torrents, and I must refer the reader to his instructive work for a full

exposition of the theory of the subject. In order, however, to show what

a concentration of destructive energies may be effected by felling the

woods that clothe and support the sides of mountain abysses, I cite his

description of a valley descending from the Col Isoard, which he calls

"a complete type of a basin of reception," that is, a gorge which serves

as a common point of accumulation and discharge for the waters of

several lateral torrents. "The aspect of the monstrous channel," says

he, "is frightful. Within a distance of less than three kilometres

[= one mile and seven eighths English], more than sixty torrents hurl

into the depths of the gorge the debris torn from its two flanks. The

smallest of these secondary torrents, if transferred to a fertile

valley, would be enough to ruin it."

The eminent political economist Blanqui, in a memoir read before the

Academy of Moral and Political Science on the 25th of November, 1843,

thus expresses himself: "Important as are the causes of impoverishment

already described, they are not to be compared to the consequences which

have followed from the two inveterate evils of the Alpine provinces of

France, the extension of clearing and the ravages of torrents. * * The

most important result of this destruction is this: that the agricultural

capital, or rather the ground itself--which, in a rapidly increasing

degree, is daily swept away by the waters--is totally lost. Signs of

unparalleled destitution are visible in all the mountain zone, and the

solitudes of those districts are assuming an indescribable character of

sterility and desolation. The gradual destruction of the woods has, in a

thousand localities, annihilated at once the springs and the fuel.

Between Grenoble and Briancon in the valley of the Romanche, many

villages are so destitute of wood that they are reduced to the necessity

of baking their bread with sun-dried cowdung, and even this they can

afford to do but once a year. This bread becomes so hard that it can be

cut only with an axe, and I have myself seen a loaf of bread in

September, at the kneading of which I was present the January previous.

"Whoever has visited the valley of Barcelonette, those of Embrun, and of

Verdun, and that Arabia Petraea of the department of the Upper Alps,

called Devoluy, knows that there is no time to lose, that in fifty years

from this date France will be separated from Savoy, as Egypt from

Syria, by a desert."[218]

It deserves to be specially noticed that the district here referred to,

though now among the most hopelessly waste in France, was very

productive even down to so late a period as the commencement of the

French Revolution. Arthur Young, writing in 1789, says: "About

Barcelonette and in the highest parts of the mountains, the hill

pastures feed a million of sheep, besides large herds of other cattle;"

and he adds: "With such a soil, and in such a climate we are not to

suppose a country barren because it is mountainous. The valleys I have

visited are, in general, beautiful."[219] He ascribes the same character

to the provinces of Dauphiny, Provence, and Auvergne, and, though he

visited, with the eye of an attentive and practised observer, many of

the scenes since blasted with the wild desolation described by Blanqui,

the Durance and a part of the course of the Loire are the only streams

he mentions as inflicting serious injury by their floods. The ravages of

the torrents had, indeed, as we have seen, commenced earlier in some

other localities, but we are authorized to infer that they were, in

Young's time, too limited in range, and relatively too insignificant, to

require notice in a general view of the provinces where they have now

ruined so large a proportion of the soil.

But I resume my citations.

"I do not exaggerate," says Blanqui. "When I shall have finished my

excursion and designated localities by their names, there will rise, I

am sure, more than one voice from the spots themselves, to attest the

rigorous exactness of this picture of their wretchedness. I have never

seen its equal even in the Kabyle villages of the province of

Constantine; for there you can travel on horseback, and you find grass

in the spring, whereas in more than fifty communes in the Alps there is

absolutely nothing.

"The clear, brilliant, Alpine sky of Embrun, of Gap, of Barcelonette,

and of Digne, which for months is without a cloud, produces droughts

interrupted only by diluvial rains like those of the tropics. The abuse

of the right of pasturage and the felling of the woods have stripped the

soil of all its grass and all its trees, and the scorching sun bakes it

to the consistence of porphyry. When moistened by the rain, as it has

neither support nor cohesion, it rolls down to the valleys, sometimes in

floods resembling black, yellow, or reddish lava, sometimes in streams

of pebbles, and even huge blocks of stone, which pour down with a

frightful roar, and in their swift course exhibit the most convulsive

movements. If you overlook from an eminence one of these landscapes

furrowed with so many ravines, it presents only images of desolation and

of death. Vast deposits of flinty pebbles, many feet in thickness, which

have rolled down and spread far over the plain, surround large trees,

bury even their tops, and rise above them, leaving to the husbandman no

longer a ray of hope. One can imagine no sadder spectacle than the deep

fissures in the flanks of the mountains, which seem to have burst forth

in eruption to cover the plains with their ruins. These gorges, under

the influence of the sun which cracks and shivers to fragments the very

rocks, and of the rain which sweeps them down, penetrate deeper and

deeper into the heart of the mountain, while the beds of the torrents

issuing from them are sometimes raised several feet, in a single year,

by the debris, so that they reach the level of the bridges, which, of

course, are then carried off. The torrent beds are recognized at a great

distance, as they issue from the mountains, and they spread themselves

over the low grounds, in fan-shaped expansions, like a mantle of stone,

sometimes ten thousand feet wide, rising high at the centre, and curving

toward the circumference till their lower edges meet the plain.

"Such is their aspect in dry weather. But no tongue can give an adequate

description of their devastations in one of those sudden floods which

resemble, in almost none of their phenomena, the action of ordinary

river water. They are now no longer overflowing brooks, but real seas,

tumbling down in cataracts, and rolling before them blocks of stone,

which are hurled forward by the shock of the waves like balls shot out

by the explosion of gunpowder. Sometimes ridges of pebbles are driven

down when the transporting torrent does not rise high enough to show

itself, and then the movement is accompanied with a roar louder than the

crash of thunder. A furious wind precedes the rushing water and

announces its approach. Then comes a violent eruption, followed by a

flow of muddy waves, and after a few hours all returns to the dreary

silence which at periods of rest marks these abodes of desolation.

"This is but an imperfect sketch of this scourge of the Alps. Its

devastations are increasing with the progress of clearing, and are every

day turning a portion of our frontier departments into barren wastes.

"The unfortunate passion for clearing manifested itself at the beginning

of the French Revolution, and has much increased under the pressure of

immediate want. It has now reached an extreme point, and must be

speedily checked, or the last inhabitant will be compelled to retreat

when the last tree falls.

"The elements of destruction are increasing in violence. Rivers might be

mentioned whose beds have been raised ten feet in a single year. The

devastation advances in geometrical progression as the higher slopes are

bared of their wood, and 'the ruin from above,' to use the words of a

peasant, 'helps to hasten the desolation below.'

"The Alps of Provence present a terrible aspect. In the more equable

climate of Northern France, one can form no conception of those parched

mountain gorges where not even a bush can be found to shelter a bird,

where, at most, the wanderer sees in summer here and there a withered

lavender, where all the springs are dried up, and where a dead silence,

hardly broken by even the hum of an insect, prevails. But if a storm

bursts forth, masses of water suddenly shoot from the mountain heights

into the shattered gulfs, waste without irrigating, deluge without

refreshing the soil they overflow in their swift descent, and leave it

even more seared than it was from want of moisture. Man at last retires

from the fearful desert, and I have, the present season, found not a

living soul in districts where I remember to have enjoyed hospitality

thirty years ago."

In 1853, ten years after the date of Blanqui's memoir, M. de Bonville,

prefect of the Lower Alps, addressed to the Government a report in which

the following passages occur:

"It is certain that the productive mould of the Alps, swept off by the

increasing violence of that curse of the mountains, the torrents, is

daily diminishing with fearful rapidity. All our Alps are wholly, or in

large proportion, bared of wood. Their soil, scorched by the sun of

Provence, cut up by the hoofs of the sheep, which, not finding on the

surface the grass they require for their sustenance, scratch the ground

in search of roots to satisfy their hunger, is periodically washed and

carried off by melting snows and summer storms.

"I will not dwell on the effects of the torrents. For sixty years they

have been too often depicted to require to be further discussed, but it

is important to show that their ravages are daily extending the range of

devastation. The bed of the Durance, which now in some places exceeds

2,000 metres [about 6,600 feet, or a mile and a quarter] in width, and,

at ordinary times, has a current of water less than 10 metres [about 33

feet] wide, shows something of the extent of the damage.[220] Where, ten

years ago, there were still woods and cultivated grounds to be seen,

there is now but a vast torrent: there is not one of our mountains which

has not at least one torrent, and new ones are daily forming.

"An indirect proof of the diminution of the soil is to be found in the

depopulation of the country. In 1852, I reported to the General Council

that, according to the census of that year, the population of the

department of the Lower Alps had fallen off no less than 5,000 souls in

the five years between 1846 and 1851.

"Unless prompt and energetic measures are taken, it is easy to fix the

epoch when the French Alps will be but a desert. The interval between

1851 and 1856 will show a further decrease of population. In 1862, the

ministry will announce a continued and progressive reduction in the

number of acres devoted to agriculture; every year will aggravate the

evil, and, in a half century, France will count more ruins, and a

department the less."

Time has verified the predictions of De Bonville. The later census

returns show a progressive diminution in the population of the

departments of the Lower Alps, the Isere, the Drome, Ariege, the Upper

and the Lower Pyrenees, the Lozere, the Ardennes, the Doubs, the Vosges,

and, in short, in all the provinces formerly remarkable for their

forests. This diminution is not to be ascribed to a passion for foreign

emigration, as in Ireland, and in parts of Germany and of Italy; it is

simply a transfer of population from one part of the empire to another,

from soils which human folly has rendered uninhabitable, by ruthlessly

depriving them of their natural advantages and securities, to provinces

where the face of the earth was so formed by nature as to need no such

safeguards, and where, consequently, she preserves her outlines in spite

of the wasteful improvidence of man.[221]

Highly colored as these pictures seem, they are not exaggerated,

although the hasty tourist through Southern France and Northern Italy,

finding little in his high road experiences to justify them, might

suppose them so. The lines of communication by locomotive train and

diligence lead generally over safer ground, and it is only when they

ascend the Alpine passes and traverse the mountain chains, that scenes

somewhat resembling those just described fall under the eye of the

ordinary traveller. But the extension of the sphere of devastation, by

the degradation of the mountains and the transportation of their debris,

is producing analogous effects upon the lower ridges of the Alps and the

plains which skirt them; and even now one needs but an hour's departure

from some great thoroughfares to reach sites where the genius of

destruction revels as wildly as in the most frightful of the abysses

which Blanqui has painted.[222]

There is one effect of the action of torrents which few travellers on

the Continent are heedless enough to pass without notice. I refer to the

elevation of the beds of mountain streams in consequence of the deposit

of the debris with which they are charged. To prevent the spread of sand

and gravel over the fields and the deluging overflow of the raging

waters, the streams are confined by walls and embankments, which are

gradually built higher and higher as the bed of the torrent is raised,

so that, to reach a river, you ascend from the fields beside it; and

sometimes the ordinary level of the stream is above the streets and even

the roofs of the towns through which it passes.[223]

The traveller who visits the depths of an Alpine ravine, observes the

length and width of the gorge and the great height and apparent solidity

of the precipitous walls which bound it, and calculates the mass of rock

required to fill the vacancy, can hardly believe that the humble

brooklet which purls at his feet has been the principal agent in

accomplishing this tremendous erosion. Closer observation will often

teach him, that the seemingly unbroken rock which overhangs the valley

is full of cracks and fissures, and really in such a state of

disintegration that every frost must bring down tons of it. If he

compute the area of the basin which finds here its only discharge, he

will perceive that a sudden thaw of the winter's deposit of snow, or one

of those terrible discharges of rain so common in the Alps, must send

forth a deluge mighty enough to sweep down the largest masses of gravel

and of rock.[224] The simple measurement of the cubical contents of the

semi-circular hillock which he climbed before he entered the gorge, the

structure and composition of which conclusively show that it must have

been washed out of this latter by torrential action, will often account

satisfactorily for the disposal of most of the matter which once filled

the ravine.